6 - Integrated Evaluation of the Boulder Reservoir Water Treatment Plant Source Water Protection andCITY OF BOULDER
WATER RESOURCES ADVISORY BOARD
AGENDA ITEM
MEETING DATE: June 28, 2007
AGENDA TITLE: Integrated Evaluation of the Boulder Reservoir Water Treatment Plant
(BRWTP) Source Water Protection and Treatment Improvements.
PREPARING DEPARTMENT:
Robert E. Williams - Director of Public Work for Utilities
Anne Noble - Utilities Project Manager
Bob Harberg - Utilities Planning and Project Management Coordinator
Bret Linenfelser - Water Quality and Environmental Services Coordinator
Randy Crittenden - Water Treatment Coordinator
Cazol Ellinghouse - Water Resources Coordinator
BOARD ACTION REQUESTED: WRAB recommendation to support the Carter Lake
Pipeline as the preferred long term capital improvement altemative for the Boulder Reservoir
Water Treatment Plant.
FISCAL IMPACT: The proposed 2008-2013 CIP includes $1 million in 2008 to design and
$25 million in 2009 to construct a pipeline from Carter Lake to the BRWTP.
PURPOSE: Attached (Attachment A) is the final report prepazed by Black & Veatch (B&V)
Consulting Engineers on the Integrated Evaluation of the Boulder Reservoir Water Treatment
Plant (BRWTP) Source Water Protection and Treatment Improvements, which recommends that
the city move forward with the construction of a pipeline from Carter Lake to the Boulder
Reservoir Water Treatment Plant. Also attached are: a peer review (Attachment B) of the B&V
report prepazed by Susumu Kawamura, Black & Veatch's response (Attachment C) to the peer
review, responses to WRAB questions submitted to staff in May 2007 (Attachment D) as well as
the analysis of the WRAB decision model scores based on scoring by Black and Veatch and
scoring by Kelly DiNatale (Attachment E).
BACKGROUND:
On Mazch 19, 2007, the draft report on the Integrated Evaluation of the Boulder Reservoir Water
Treatment Plant (BRWTP) Source Water Protection and Treatment Improvements was presented
to the Water Resources Advisory Board. At the time, seven altematives were identified and
AGENDA ITEM # Page 1
evaluated. All of the alternatives assumed the wnstruction of mid-term improvements at the
treatment plant which includes treatment with chlorine dioxide (C102). These alternatives
assumed three source water options: seasonal use of the Boulder Feeder Canal, yeaz-round use of
the Boulder Reservoir and the Carter Lake Pipeline. Treatment processes were paired with each
of these source water options and the alternatives were evaluated based on a performance
ranking, as well as the present worth cost. At the April 16, 2007 and May 21, 2007 WRAB
meetings, staff provided additional information in response to questions and comments from the
Water Resources Advisory Boazd, including the evaluation of inembrane filtration as an
alternative and the evaluation of the alternatives using criteria and scoring provided by the
WRAB. In May, 2007, in order to simplify the evaluation process, the number of alternatives
was reduced to six, based on the assumption that the BRWTP would continue to utilize both of
the current water sources or a pipeline from Carter Lake would be constructed.
ANALYSIS:
The six alternatives that were brought forwazd in the final report include:
• Alternative 1: Chlorine Dioxide (C102) only
• Alternative 2: C102 and Ultraviolet (LJV)
• Alternative 3:C102, UV and Granular Activated Cazbon (GAC)
• Alternative 4: C102 and Membrane Filtration/Ultrafiltration (MFNF)
• Alternative 5: C102 and Advanced Oxidation Process (Ozone)
• Alternative 6: C102 and Carter Lake Pipeline
A decision process for evaluating the alternatives was developed that utilized a performance
ranking as well as a net present cost. Criteria were developed by city staff to rank each of these
alternatives. Each criterion was weighted based on the consensus of its relative importance. The
six final altematives were numerically rated based on their ability to meet each criterion. The
criteria, relative weighting and performance score for each altemative aze shown in Chapter 6 of
the report and are summarized in Attachment E of this memorandum, along with the WRAB
Decision Model Scores. The WRAB developed a sepazate decision model, which evaluated the
altematives based on eight criteria, including cost. Four WRAB members individually
developed relative weights for these criteria, which were then used to score the alternatives.
Black & Veatch scored the aiternatives based on their assessment of eacli altemative to meet the
criteria. The alternatives were also scored by Kelly DiNatale.
The first three alternatives would not meet the city's water quality goals with respect to TDS and
sulfates when raw water is provided from the reservoir. Alternative 1, the baseline alternative,
would not meet the city's water quality goals with respect to pathogens and does not provide an
effective organic micro-pollutant barrier. With the addition of UV disinfection, Alternative 2,
provides adequate pathogen inactivation, but this alternative would not provide an effective
barrier for organic micro-pollutants. With the addition of GAC, Altemative 3, the concern of
organic micro-pollutants would be addressed. Alternative 4, membrane filtration, addresses
pathogens, but not micro-pollutants or TDS and sulfate. Alternative 5, advanced oxidation
(ozone) provides barriers for pathogens and micro-pollutants, but not TDS and Sulfates.
Alternative 6, the Carter Lake Pipeline meets all of the city's water quality goals and provides at
least one barrier for each contaminant category evaluated.
AGENDA ITEM # Page 2
A net present cost was calculated for each altemative, taking into account both capital and
operations and maintenance costs. A 30 year life cycle was assumed for treatment plant
processes, with a 70 yeaz life cycle for the pipeline. The remaining value of the pipeline was
credited back in the net present cost evaluation. Operations and maintenance costs included
power, chemicals and consumables. The cost of staffing the facility was not included as it was
assumed to be constant for all of the alternatives. Capital costs were not included for the mid-
term treatment plant improvements. However, maintenance costs for the mid-term
improvements were included in all of the alternatives as it was assumed these unprovements
would be completed prior to the long-term improvements. The present worth cost, capital cost
and operations and maintenance (O&M) costs (in $million) aze described in chapter 7 of the
report and are shown below:
Alternative Description Present Worth Cost Capital Cost O&M Costs
1 C102 only $5.2 $0 $0.17
2 C102 & UV $93 $2.4 $0.21
3 C102 & UV & GAC $53.4 $21.9 $0.86
4 C102 & MF/UF $293 $13.2 $0.42
5 CI02 & Ozone $26.9 $13.6 $033
6 C102 & Pipeline $17.2 $21.1 $0.19
RECOMMENDATION
Staff recommends moving forward with the Carter Lake Pipeline. Protection of the BRWTP
source water through investing in the construction of the Carter Lake Pipeline will provide long-
term benefits to the city. The city is placing a greater reliance on this facility than in the past due
to continued planned growth in the city's water service azea. Even though current regulatory
requirements are being met, the risk of contaminants entering the source water and passing
through the treatment process still exists. Investing in a pipeline that will protect the source
water for the BRWTP faz into the future is a worthwhile investment similaz to that undertaken by
prior generations with the Silver Lake Watershed.
The quality of water in Carter Lake is excellent. It is a deep reservoir with a small natural runoff
azea and is filled mostly with high quality water imported from the Western Slope. These factors
are significantly different than factors affecting water quality in the Boulder Feeder Canal and
Boulder Reservoir, both of which are negatively affected by a much more significant area of
existing development and agriculture. Future development and agricultural practices will likely
exacerbate these negative effects. The threat of accidental or intentional contamination is also a
concern because of limited ability to react or dilute such contamination.
The city of Boulder is currently participating in the development of right-of-way acquisition
plans and permit applications for the Southem Water Supply Project II (Carter Lake Pipeline).
Other participants include Little Thompson Water District, the town of Frederick and Left Hand
Water District. The pipeline is estimated to cost $33 million. Depending upon the number of
participants, the city of Boulder's shaze of the cost can range from $20 to $25 million. Attached
are excerpts from the Northern Colorado Water Conservancy District (NCWCD) Southern Water
AGENDA ITEM # Page 3
Supply Project II Feasibility Study prepared by Integra Engineering in January, 2006 (Attachment
F).
The Carter Lake Pipeline will address both the neaz-term and potential increase in degradation to
water quality of the BRWTP. Although water treatment technology has advanced, treatment
processes do fail. Preventing source water contamination provides a more robust barrier than
subsequent treatment. The Carter Lake Pipeline would also provide a much more uniform water
quality, substantially simplifying the treatment optimization and increasing treatment process
reliability. Although the capital cost of the Carter Lake Pipeline is significant, it is comparable to
the cost of treatment technologies that afford a similar level of water quality protection and with
the assurance that contaminants will be prevented from entering the city's source water in the
first place, rather than attempting to remove these contaminants via treatment.
The pipeline would also provide opportunities and flexibility for improvements in the
management and operation of the city's raw water facilities. These include possible hydroelectric
power generation as well as improvements in the flexibility of use of the City's various water
sources for the BRWTP. This increased flexibility could provide a slight increase in the drought
yeaz yield of the City's water rights portfolio.
Water source selection flexibility would be improved by providing a redundant means of
supplying BRWTP. At present, source options include drawing directly from the Boulder Feeder
Canal or pumping from Boulder Reservoir. Since the canal is shut down from about November
to April of each year, the Carter Lake Pipeline would provide a second option for water delivery
to BRWTP in the winter months. If one of the present source options is unavailable for
operational reasons, such as a power outage to the pumps or herbicide spraying on the canal, the
Carter Lake Pipeline would provide the flexibility of an additional means of providing water.
It is likely that if the Carter Lake Pipeline were built that it would be used as the sole means of
supplying BRWTP at most times, but the options of using Boulder Reservoir water or canal
water would remain for use during drought or emergency. This increased flexibility in water
supply facilities at BRWTP might provide a slight increase in the yield ofthe City's Windy Gap
water supplies during drought periods. If the City is able to access its CBT allotment directly
from the storage pool in Carter Lake during the winter, the City's winter Boulder Reservoir
account can be filled with Windy Gap water each year. At present, it is filled with CBT water
from the allotment given in the yeaz that is closing. If this close-out CBT allotment can be
accessed from Carter Lake during the winter, it would no longer need to be placed in Boulder
Reservoir storage before the canal shuts down in the fall. lf the Windy Gap water that is then
stored in Boulder Reservoir for the winter is not delivered into the BRW"I'P over the course of
the winter, it can be exchanged up to Bazker Reservoir in the spring for later use at Betasso. The
increased availability of storage space for Windy Gap water and the increased ability to exchange
Windy Gap effluent back into the City's water system until it is fully consumed might provide a
slight increase in water yield during moderately dry periods when exchange potential exists. This
in turn would allow the City to carryover higher amounts of CBT water under the City's account
within the CBT storage reservoirs that could be used during drought periods
AGENDA ITEM # Page 4
The cost of the pipeline as currently proposed is less than it might be at a later time because there
is an opportunity to shaze costs in constructing the Carter Lake pipeline with other communities.
Additionally, on-going construction cost inflation suggests that the cost of constructing the
pipeline will only increase in the future. The majority of the pipeline right-of-way (ROW) has
been previously secured by the NCWCD. Continued development pressure along this ROW may
malce future construction more difficult. Securing the remaining ROW for a pipeline at this time
is also considered important because of these development pressures. Also, the cost of borrowing
money is near an all time low. These factors suggest that now is a good time to proceed with this
project as a long term investment in the city's water utility infrastructure.
ATTACHMENTS:
Attachment A: Final Report on the Integrated Evaluation of Boulder Reservoir Water
Treatment Plant (BRWTP) Source Water Protection and Treatment
Improvements prepared by Black & Veatch Consulting Engineers, june 18,
2007.
Attachment B: Peer Review for the Draft Report on Boulder Reservoir Water Plant
prepared by Susumu Kawamura dated May 31, 2007
Attachment C: B&V's Responses to the Peer Review
Attachment D: Questions and Answers on the Integrated Evaluation of the Boulder
Reservoir Water Treatment Plant Source Water Protection and Treatment
Improvements dated June 2007
Attachment E: WRAB Decision Model scored by B&V and scored by Kelly DiNatale
Attachment F: Excerpts from the Southern Water Supply Project II Feasibility Study
AGENDA ITEM # Page 5
A1T19 C I-i M E N T A
~ BLACK & VEATCH
~ Bailding a {~/pr~~J of difference°
Energy Water Information Government
Integrated Evaluation of Boulder Reservoir Water
Treatment Facility Source Water Protection and
Treatment Improvements Study
Prepared for:
City of Boulder Utilities Division
1739 Broadway Street
Boulder, Colorado 80306
Prepared By:
Black & Veatch Corporation
6300 South Syracuse Way
Suite 300
Centennial, Colorado 80111
Project 144922.0210
June 18, 2007
~ . ..•t ~,~'t ~; "~:~ •,~.\
INTEGRATED SOURCE WATER AND TREATMENT STUDY
Table of Confents
Contents
Paae
Executive Summary ...................................................................................... ES-1
A. Overview ................................................................................. ES-1
B. Background ............................................................................. ES-2
C. Source Water Quality Evaluation ............................................. ES-2
D. Contaminant Barrier Requirements ......................................... ES-3
E. Multi-BarrierAlternatives Performance Evaluation .................. ES-4
F. Multi-Barrier Water Delivery Alternatives ................................. ES-5
G. Non-Economic Performance of BRWTF Water
Delivery Alternatives ................................................................ ES-7
H. Cost Opinions .......................................................................... ES-8
I. Preferred Water Delivery Alternatives ..................................... ES-9
Chapter 1 - Introduction ............................................................................... 1-1
A. Purpose ...................................................................................1-1
B. ProjectBackground .................................................................1-1
C. Regulatory Environment and City Water
Quality Goals ........................................................................... 1-4
1. Regulatory Environment ............................................... 1-4
2. City Drinking Water Quality Goals ................................ 1-5
D. Contaminant Barrier Requirements ......................................... 1-6
E. Multi-Barrier Alternatives Pertormance Evaluation .................. 1-6
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INTECaRATED SOURCE WATER AND TREATMENT STUDY
Table of Confents
Contents - Continued
Paae
1. State the Decision .................................................. ....... 1-7
2. Develop the Objectives .......................................... ....... 1-7
3. Classify the Objectives into Musts and Wants ....... ....... 1-7
4. Weigh the Wants ................................................... ....... 1-8
5. Generate Alternatives ............................................ ....... 1-8
6. Screen the Alternatives Through the Musts ........... ....... 1-8
7. Compare the Alternatives Against the Wants ........ ....... 1-8
8. Consider the Adverse Consequences ................... ....... 1-8
9. Make the Best Balanced Decision ......................... ....... 1-9
Chapter 2- Source Water Quality ......................................................... ....... 2-1
A Existing BRWTF Source Water System ........................... ....... 2-1
1. Boulder Feeder Canal ............................................ ....... 2-1
2. Boulder Reservoir .................................................. ....... 2-2
B. Water Quality Data Sources ............................................. ....... 2-3
C. Sou rce Water Quality Data Summary ............................... ....... 2-3
1. Carter Lake ............................................................ ....... 2-3
a. Microbial Characteristics ............................. ....... 2-7
b. Physical Characteristics .............................. ....... 2-7
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INTEGRATED SOURCE WATER AND TREATMENT STUDY
Table of Contents
Contents - Continued
D.
E
Paae
c. Chemical Characteristics ........................ ........... 2-8
2. Boulder Feeder Canal ........................................ ........... 2-8
a. Microbial Characteristics ......................... ........... 2-8
b. Physical Characteristics .......................... ........... 2-10
c. Chemical Characteristics ........................ ........... 2-10
3. Boulder Reservoir .............................................. ........... 2-11
a. Microbial Characteristics .................. ...... ........... 2-11
b. Physical Characteristics .......................... ........... 2-12
c. Chemical Characteristics ........................ ........... 2-12
d. Seasonal Water Quality Variation ........... ........... 2-13
BRWTF Operational Data ............................................. ........... 2-14
1. pH ...................................................................... ...........2-15
2. TOC Removal .................................................... ........... 2-15
3. Disinfection Byproduct Formation ...................... ........... 2-15
4. Total Dissolved Solids and Sulfate ............. ...... ........... 2-15
Summary of BRWTF Source Water Quality ................. ........... 2-16
1. Microbial Source Water Quality Data ................. ........... 2-16
2. Physical and Chemical Source Water
Quality Data ...................................................... ............ 2-17
3. BRWTF Operational Water Quality Data .... ..... ............ 2-17
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INTEGRATED SOURCE WATER AND TREATMENT STUDY
Table of Contents
Contents - Continued
Pa4e
F. Sustainability of Carter Lake as a BRWTF Source ................ .. 2-17
1. Physical and Chemical Water Quality Trends ............. .. 2-18
2. Trophic Status ............................................................. .. 2-18
3. Watershed Protection ................................................. .. 2-19
4. CBT System Operation ............................................... .. 2-20
5. Potential for Contamination by Pathogens .................. .. 2-20
Chapter 3- Delivery Alternative Contaminant Barriers ............................... .. 3-1
A. Barriers for Microbial Pathogen Control ................................. .. 3-2
1. Overview ..................................................................... .. 3-2
2. Existing Barriers for Microbial Pathogen
Control ........................................................................ .. 3-5
3. Potential Additional Barriers for Microbial Pathogen
Control ........................................................................ .. 3-5
B. Barriers for Disinfection Byproduct Control ............................ .. 3-7
1. Overview ..................................................................... .. 3-7
2. Existing Barriers for DBP Control ................................ .. 3-8
3. Potential Additional Barriers for DBP Control .............. .. 3-8
C. Barriers for Organic Micro-Pollutant Control .......................... .. 3-10
1. Overview .................................................................... ... 3-10
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1NTEGRATED SOURCE WATER AND TREATMENT STUDY
Table of Contents
Contents - Continued
Pape
2. Existing Barriers for Organic
Micropollutant Control ................................................... 3-11
3. Potential Additional Barriers for Organic
Micropollutant Control ................................................... 3-11
D. Barriers for Manganese Control .............................................. 3-12
1. Overview ....................................................................... 3-12
2. Existing Barriers for Manganese Control ...................... 3-12
3. Potential Additional Barriers for
Manganese Control ...................................................... 3-13
E. Barriers for Taste an Odor Control .......................................... 3-13
1. Overview ....................................................................... 3-13
2. Existing Barriers for Taste and Odor Control ................ 3-14
3. Potential Additional Barriers for Taste and
Odor Control ................................................................. 3-14
F. Barriers for Inorganic Contaminant Control ............................. 3-14
1. Overview ....................................................................... 3-15
2. Existing Barriers for Inorganic Contaminant
Control .......................................................................... 3-15
3. Potential Additional Barriers for Inorganic
Contaminant Control ..................................................... 3-15
Chapter 4- Muiti-Barrier Approach Decision Criteria ................................... 4-1
A. Mandatory Must Criteria .......................................................... 4-1
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INTEGRATED SOURCE WATER AND TREATMENT STUDY
Table of Contents
Contents - Continued
Paae
1. Regulatory Compliance ................................................ 4-1
2. Water Rights Portfolio Yield .......................................... 4-2
B. Desirable Want Criteria ........................................................... 4-2
1. Finished Water Quality Criteria ..................................... 4-3
2. Source Water Portfolio Criteria ..................................... 4-4
3. Water Treatment and Operations Criteria ..................... 4-5
4. Risk Criteria ..................................................................4-6
5. Environmental and Public Acceptance Criteria ............. 4-7
Chapter 5- Multi-Barrier Approach Alternatives ........................................... 5-1
A. Conceptual Improvement Screening ....................................... 5-1
1. Source Water Protection ............................................... 5-1
2. Prefiltration ....................................................................5-2
3. Treatment PerFormance ................................................ 5-2
4. Additional Filtration ....................................................... 5-2
5. Oxidation/Inactivation ................................................... 5-3
6. GAC Adsorption ............................................................ 5-3
B. Grouping Conceptual Improvements into
Delivery Alternatives ................................................................ 5-3
1. BFC and Boulder Reservoir Seasonal
Delivery Alternatives ..................................................... 5-4
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INTEGRATED SDURCE WATER AND TREATMENT STUDY
Table of Gontents
Contents - Continued
Paqe
2. Carter Lake Pipeline Delivery Alternative ..................... 5-5
3. Water Delivery Alternatives Summary .......................... 5-6
Chapter 6- Non-Economic Performance Evaluation .................................... 6-1
A. Non-Economic Performance Criteria Weighting ...................... 6-1
B. BRWTF Multi-Barrier Alternative Pertormance Scores ........... 6-3
C. Alternative Performance sensitivity Analysis ........................... 6-3
Chapter 7- Multi-Barrier Approach Economic Evaluation ............................. 7-1
A. Economic Evaluation Principles and Parameters .................... 7-1
B. CapitalCostOpinions ..............................................................7-2
C. O&M Cost Opinions ................................................................. 7-2
D. Net Present Value Opinions .................................................... 7-3
Chapter 8- Preferred BRWTF Multi-Barrier Alternative ................................ 8-1
A. Cost-Performance Comparison ............................................... 8-1
B. Preferred BRWTF Water Delivery Alternative ......................... 8-1
Tables
Table ES-1 Non-Economic Performance Scores ......................................... ES-7
Table ES-2 Cost Opinions in Millions of Dollars ........................................... ES-8
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~ INTEGRATED SOURCE WATER AND TREATMENT STUDY
'^ Table of Contents
.
Table 1-1 Boulder Feeder Canal and Boulder Reservoir
Vulnerabilities to Water Quality Degradation ........................... 1-2
Table 2-1 Water Quality Data Sources .................................................... 2-4
Table 2-2 Average Water Quality Data for Carter Lake,
Boulder Feeder Canal, and Boulder Reservoir ........................ 2-6
Table 3-1 LT2ESWTR Cryptosporidum Treatment Requirements
for Conventional WTPs ............................................................ 3-3
Table 3-2 Required and Target Log-Removal/Inactivation
for Regulated Microbial Pathogens .......................................... 3-4
Table 3-3 Regulatory Requirements and Additional
Pathogen Removal/Inactivation to Meeting City
Goals at BRWTF ..................................................................... 3-5
Table 3-4 LT2ESWTR Mocrobial Toolbox .............................................. 3-6
Table 3-5 Percent TOC Removal Required by Enhanced
Coagulation for Surface Water Systems Utilizing
Conventional Treatment .......................................................... 3-10
Table 4-1 Finished Water Quality Criteria for BRWTF
Multi-Barrier Water Delivery Alternatives ................................. 4-3
Table 4-2 Source Water Portfolio Criteria for BRWTF
Water Delivery Alternatives ..................................................... 4-4
Table 4-3 Water Treatment and Operations Criteria for
BRWTF Water Delivery Alternatives ........................................ 4-5
Table 4-4 Risk Criteria for BRWfF Water Delivery Alternatives .............. 4-6
Table 4-5 Environmental and Public Acceptance Criteria for
BRWTF Water Delivery Alternatives ........................................ 4-7
Table 5-1 Barriers for Water Quality Vulnerabilities at BRWTF ............... 5-7
Table 5-2 Microbial Pathogen Barriers for BRWTF Delivery
Alternatives .............................................................................. 5-8
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lNTEGRATED SOURCE WATER AND TREATMENT STUDY
Table of Contents
Tables - Continued
Paqe
Table 6-1 BRWTF Performance Criteria Weights and
Water Delivery Alternative Scores ........................................... 6-2
Figures
Follows
Paae
Figure 1-1 Raw Water Supply Route .........................................................1-1
Figure 1-2 Outfalls, Erosion, and Road Crossings on Boulder
Feeder Canal ............................................................................1-2
Figure 1-3 Outfalls and Stormwater Diversions to Boulder
Feeder Canal ........................................................................... 1-2
Figure 2-1 Total Dissolved Solids and Sulfate in Carter Lake ................... 2-8
Figure 2-2 Historical Fecai Coliform Concentrations in BFC ..................... 2-9
Figure 2-3 Cumulative Frequency of Bacterial
Contamination in BFC ............................................................. 2-9
Figure 2-4 Elevated E. Coli Contamination Episodes in BFC -
Spatial Variation ...................................................................... 2-9
Figure 2-5 Elevated E. Coli Contamination Episodes in BFC -
Temporal Variation .................................................................. 2-9
Figure 2-6 Total Dissolved Solids and Sulfate in BFC .............................. 2-10
Figure 2-7 Historical Fecal Coliform Concentrations in
Boulder Reservoir Hypolimnion ............................................... 2-11
Figure 2-8 Total Dissolved Solids and Sulfate in
Boulder Reservoir .................................................................... 2-12
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.. INTEGRATED SOURCE WATER AND TREATMENT STt1DY
~ Table of Contents
Figures - Continued
Follows
Paqe
Figure 2-9 Effect of Thermal Stratification on Dissolved Oxygen
Manganese, and Sulfate Concentrations in Boulder
Reservoir Hypolimnion ............................................................ 2-13
Figure 2-10 Water Temperatures in BFC and Boulder Reservoir ............... 2-13
Figure 2-11 Microbial Energy Generation through Preferential
Respiration with Inorganic Terminal Electron Acceptors ......... 2-14
Figure 2-12 Hydraulics of Thermally Generated Vertical Stratifications
in Boulder Reservoir ................................................................ 2-14
Figure 2-13 Boulder Reservoir Water Treatment Facility
Finished Water pH ................................................................... 2-15
Figure 2-14 Boulder Reservoir Water Treatment Facility
TOC Removal .......................................................................... 2-15
Figure 2-15 Boulder Reservoir Water Treatment Facility
Finished Water TTHM ............................................................. 2-15
Figure 2-16 Boulder Reservoir Water Treatment Facility
Finished Water HAA5 .............................................................. 2-15
Figure 2-17 Boulder Reservoir Water Treatment Facility
Finished Water TDS and Sulfate ............................................. 2-16
Figure 2-18 pH and Alkalinity in Carter Lake ................................... ........... 2-18
Figure 2-19 Hypolimnetic Dissolved O~rygen in Carter Lake ............ ........... 2-18
Figure 2-20 Secchi Depth in Carter Lake ......................................... ........... 2-18
Figure 2-21 Total Phosphorus in Carter Lake .................................. ........... 2-18
Figure 2-22 Chlorophyll a in Carter Lake ......................................... ........... 2-18
Figure 2-23 Carter Lake Watershed Topography ............................ ........... 2-19
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INTEGRATED SOURCE WATER AND TREATMENT STUDY
Tab/e of Confents
Figures - Continued
Follows
Paqe
Figure 2-24 Colorado-Big Thompson Project Supply to Carter Lake.......... 2-19
Figure 5-1 Alternative 1: Boulder Feeder Canal/Boulder
Reservoir Seasonal Delivery with CIO2 Pre-oxidation ............. 5-4
Figure 5-2 Alternative 2: Boulder Feeder Canal/Boulder
Reservoir Seasonal Delivery with CIOZ Pre-oxidation
and UV Disinfection ................................................................. 5-4
Figure 5-3 Alternative 3: Boulder Feeder Canal/Boulder
Reservoir Seasonal Delivery with CIOZ Pre-oxidation,
GAC Adsorption and UV Disinfection ...................................... 5-4
Figure 5-4 Alternative 4: Boulder Feeder Canal/Boulder
Reservoir Seasonal Delivery with CIOZ Pre-oxidation
and Submerged MF/UF ........................................................... 5-4
Figure 5-5 Alternative 5: Boulder Feeder Canal/Boulder
Reservoir Seasonal Delivery with CIOZ Pre-oxidation
and Advanced Oxidation ......................................................... 5-4
Figure 5-6 Alternative 6: Carter Lake Pipeline Delivery with
CIO2 Pre-oxidation ................................................................... 5-5
Figure 6-1 K-T~' Decision Analysis Model for BRWTF
Multi-Barrier Approach Water Delivery Alternative
Selection .................................................................................. 6-1
Figure 6-2 BRWTF Multi-Barrier Water Delivery Aiternative
Ranking Sensitivity: Pathogens Criterion ................................ 6-4
Figure 7-1 Capital Costs for BRWTF Multi-Barrier Approach
Water Delivery Alternatives in 2007 Dollars ............................ 7-2
Figure 7-2 Present Value of Capital Costs for BRWTF Multi-
Barrier approach Water Delivery Alternatives .......................... 7-2
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INTEGRATED SOURCE WATER AND TREATMENT STUDY
Table of Contents
Figures - Continued
Follows
Pape
Figure 7-3 Annual O&M Costs for BRWTF Multi-Barrier
Approach Water Delivery Alternatives in 2007 Dollars ............ 7-3
Figure 7-4 Present Value of O&M Costs for BRWTF Multi-Barrier
Approach Water Delivery Alternatives ..................................... 7-3
Figure 7-5 Net Present Value of BRWTF Multi-Barrier
Approach Water Delivery Alternative Selection ....................... 7-3
Figure 8-1 Cost-Pertormance Comparison for BRWTF Water
Delivery Altematives ................................................................ 8-1
Appendices
Appendix 1- City Water Quality and Operational Goals
Appendix 2- Decision Model Criteria and Alternative Scoring
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BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Executive Summary
Executive Summary
The Integrated Evaluation of Boulder Reservoir Water Treatment Facility
Source Water Protection and Treatment Study (Integrated Study) was performed
within the conte~ of an ongoing effort by the City of Boulder (City) to.establish
definitive drinking water quality and quantity goals as a framework for planning
and implementing future improvements throughout the City's drinking water
system. One central strategy for achieving the City's water quality goals is to
implement a multi-barrier approach to protecting the City's drinking water supply
from both biological and chemical contaminants. Barriers may include source
water protection measures that either reduce or prevent introduction of
contaminants, or minimize their passage throughout the drinking water system
through treatment. A multi-barrier strategy to control drinking water contaminants
provides superior public health protection. The purpose of the Integrated Study
is to evaluate source water protection alternatives and treatment alternatives
from previous work conducted for the City and develop a long-term plan for
meeting regulatory and City water quality goa/s at the Boulder Reservoir Water
Treatment Facility (BRWTF).
A. Overview
In 2003, the Source Water Quality Protection Study (Phase 1 Study) was
completed by Black & Veatch to identify and evaluate aiternative approaches to
improve and protect source water quality for the BRWTF, based on forecasted
regulatory requirements as well as internal City-established goals. This study
recommended that raw water be conveyed by gravity fiow from Carter Lake to
BRWTF in a dedicated pipeline year-round. Concurrently, the Predesign Report
for Near-Term Improvements for the Boulder Reservoir Water Treatment Plant
(Predesign Report) was completed by MWH, which presented near-term, mid-
term and long-term recommendations for improvements at BRWTF. Near-term
improvements were completed in 2005 and included the installation of dissolved
air flotation (DAF) pre-treatment facilities, bafFling the clearwell, and providing on-
site residuals lagoons. The City has begun the budget planning process for the
addition of mid-term improvements at BRWTF, which inciude chlorine dioxide
iaaszzzio ES-1 osnaio~
BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Executive Summary
pre-oxidation, pre-sedimentation, filter backwash water treatment, and pH
adjustment. The Pre-design Report also recommended evaluation of ultraviolet
(UV) disinfection, membrane technologies, ozone oxidation, and granular
activated carbon (GAC) adsorption as potential treatment processes as part of a
long-term multi-barrier water delivery strategy for BRWTF. For the purposes of
this assessment mid-term improvements are assumed to be included in the
BRWTF treatment process train, and addition of long-term improvements was
evaluated based on this updated baseline treatment capability.
B. Background
Raw water is conveyed to BRV1(TF from Carter Lake through a 21-mile
long, open, earthen canal, referred to as the Boulder Feeder Canal (BFC), which
ultimately discharges into Boulder Reservoir (Figure 1-1). Between April and
October, the City diverts raw water from BFC just upstream of Boulder Reservoir
and delivers it through a pipeline directly to BRWTF. During the remaining
months, when BFC is not in operation, raw water is pumped from Boulder
Reservoir to BRWTF for treatment. Both BFC and Boulder Reservoir have
several features that make them vulnerable to source water quality degradation,
as listed in Table 1-1 and shown on Figures 1-2 and 1-3.
C. Source Water Quality Evaluation
Review and extensive analysis of existing historical biological, physical,
and chemical water quality data for potential raw water sources for BRWTF,
including Carter Lake, BFC, and Boulder Reservoir, was pertormed. Based on
this evaluation, B&V be/ieves that Carter Lake has superior overall water quality
as a raw water source for BRWTF compared with BFC and Boulder Reservoir.
Although Carter Lake is ultimately the source of all raw water for BRWfF,
conveyance through BFC and storage in Boulder Reservoir lead to substantial
degradation in a number of water quality parameters. Of particular concern are
the introduction of chemical contaminants and pathogenic microorganisms during
raw water conveyance through BFC and storage in Boulder Reservoir, as well as
increased salt content due to dissolution of naturally occurring minerals in
Boulder Reservoir sediments. Also of concern are objectionable tastes and
odors that result from seasonal algal blooms and increased manganese levels
inaszzzio ES-2 oenaro~
BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Executive Summary
due to o~rygen depletion in Boulder Reservoir. Carter Lake is much less
susceptible to these types of water quality degradation because of its
surrounding topography and the protected status of the Colorado-Big Thompson
Project lakes, reservoirs, and tunnels that supply its water. Analysis of 35 years
of historical data for Carter Lake do not indicate any long-term degradation in the
overall water quality, and 8&V believes that the water quality of Carter Lake will
continue to be suitable as a water source for BRWTF for decades to come.
D. Contaminant Barrier Requirements
The BRWTF currently meets or exceeds all National Primary and
Secondary drinking water regulations during routine operation, and based on
source water quality data reviewed, will likely continue to do so for the
foreseeable future. However, finished water quality in areas served by BRWTF
is vulnerable to short-term degradation due to seasonal variation in Boulder
Reservoir water quality and acute contamination episodes in either BFC or
Boulder Reservoir. Of particular concern are microbial contamination in BFC or
Boulder Reservoir, disinfection byproduct formation during treatment and
distribution, contamination by organic micro-pollutants in BFC and Boulder
Reservoir, seasonal manganese uptake, taste or odor episodes in Boulder
Reservoir, and non-uniform total dissolved solids (TDS) and sulfate concentration
across the distribution system when BRWTF uses Boulder Reservoir as its
source.
The City has established a set of drinking water quality goals and
operational treatment practices in order to ensure public health, minimize
distribution system deterioration, and provide uniformly high quality water to all its
customers. Several of the City's drinking water quality goals are more stringent
than standards required by state and federal drinking water regulations
(Appendix 1), in some instances based on prudent concerns related to public
health and in others to enhance the palatability and uniformity of finished drinking
water. Specific City drinking water goals that exceed mandated regulatory
standards include turbidity (health), microbial pathogens (health), disinfection
byproducts (health), taste and odor (aesthetic), sodium (uniformity), sulfate
(uniformity), total dissolved solids (uniformity), fluoride (health), manganese
(aesthetic), and pH (deterioration). Because the City relies on iwo separate
iaasz22io ES-3 osnaio~
BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Executive Summary
facilities supplied with source waters of seasonally differing water quality, there
are inherent operational challenges and potential cost implications associated
with meeting its drinking water qualiry goals, as discussed throughout this report.
For the purposes of this study, the minimum contaminant barrier
requirements were those specified by enforceable USEPA and CDPHE Primary
Drinking Water Standards. Contaminant barriers associated with Secondary
Drinking Water Standards and City drinking water quality goals were also
evaluated in this report. However, the contaminant barriers considered were not
required to completely satisfy these non-enforceable secondary standards in all
cases, largely for compelling economic reasons. The barrier requirements for
BRWTF, based on current state and federal regulatory requirements and City
water quality goals, were identified through review of source water quality data
for Carter Lake and BFC, and operational data from BRWTF. Barriers for
microbial pathogens, disinfection byproducts (DBPs), organic micro-pollutants,
manganese, taste and odor, and inorganic contaminant control were evaluated.
E. Multi-Barrier Alternatives Performance Evaluation
The relative performance of multi-barrier water delivery alternatives
developed in this study was evaluated using the Kepner-Tregoe~ (K-T~) decision
analysis procedure. K-T~ Decision Analysis is a systematic procedure that
encompasses the fundamental thought pattern people use to make choices.
Pertormance criteria in K-T~ decision analysis are classified either as MUST
criteria that each candidate problem solution must absolutely satisfy in order to
be included in the decision process, or WANT criteria that are desirable but not
mandatory for each candidate problem solution to satisfy. Two MUST decision
criteria were considered including Regulatory Compiiance and Water Rights
Portfolio Yield. Twenty-eight WANT criteria in five categories including Finished
Water Quality, Source Water, Treatment Operations, Risk, and Environmental
and Public Acceptance were evaluated in the decision process. An ad hoc City
staff committee representing drinking water quality, water resources, operations,
and senior management functions assigned weights to the set of WANT criteria
to establish the relative importance of each in ranking BRWTF water delivery
alternatives based on the collective expertise and experience of the committee
members.
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BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Executive Summary
F. Multi-Barrier Water Delivery Alternatives
Conceptual improvements that could be included in a multi-barrier water
delivery alternative at BRWTF were screened for applicability based on several
factors including integration with the existing treatment process train, probable
pertormance, and economic considerations. Potential conceptual improvements
were evaluated based on their ability to address one or more of the contaminant
barriers identified including microbial pathogens, DBPs, organic micropollutants,
manganese, taste and odor, and TDS and sulfate. The general strategy of the
screening process was to give greater consideration to conceptual alternatives
that where possible addressed more than one contaminant barrier, thereby
minimizing the number of conceptual improvements and complexity of proposed
multi-barrier water deliver alternatives.
Candidate multi-barrier approaches were developed for BRWTF by
combining conceptual improvements that address identified drinking water quality
vulnerabilities in source water conveyance to and treatment at BRWTF. Only
those conveyance and treatment barriers that were selected in the screening
process previously described were included in BRWTF multi-barrier alternatives.
The combination of conceptual improvements selected for each delivery
alternative was based on providing process redundancy and operational
continuity at BRWTF.
Not all possible combinations of screened barriers were included in
alternative evaluations, but each screened barrier was incorporated in at least
one water delivery alternative. The multi-barrier delivery alternatives developed
for this study would produce finished water that meets all current state and
federal drinking water standards; however, it is important to note that not all of
these alternatives continuously meet the City's drinking water goals.
• Alternative 1: This water delivery aiternative incorporates
preoxidation with chlorine dioxide followed by full conventional
treatment and free chlorine disinfection. A centralized contact
basin for preoxidation contact time is included to allow use of both
BFC and Boulder Reservoir raw water sources. Presedimentation
for turbidity and suspended solids control would also be provided
by the preoxidation contact basin, but because no coagulant would
~aaszzz~o ES-5 osnaim
BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Executive Summary
be added prior to basin contact no credit towards Cryptosporidium
treatment would be provided. Residual chlorine dioxide and
chlorite would be quenched by ferrous sulfate addition prior to
coagulation.
This barrier combination serves as the baseline BRWTF
multi-barrier water delivery alternative. This baseline alternative
would not meet the City's water quality goals with respect to
pathogen control, nor would it meet finished water TDS and sulfate
goals when raw water is provided from Boulder Reservoir. No
effective barrier for organic micropollutant control is provided by this
alternative.
Alternative 2: This alternative incorporates UV disinfection with the
barriers provided by Alternative 1. This alternative would not meet
the City's TDS and sulfate water quality goals when Boulder
Reservoir was online, nor would it provide an effective barrier for
organic micropollutant control.
Alternative 3: This alternative adds both GAC adsorption and UV
disinfection to the contaminant barriers provided by baseline
Alternative 1. This alternative would not meet the City's TDS and
sulfate water quality goals when raw water was supplied from
Boulder Reservoir.
Alternative 4: This alternative utilizes the contaminant barriers in
baseline Alternative 1 with granular media filtration replaced by
submerged low-pressure membrane filtration retrofitted into the
existing filter boxes. This altemative would not meet the City's
TDS and sulfate water quality goals, nor would it provide an
effective barrier for organic micropollutant control.
Alternative 5: This alternative adds ozone oxidation to the
contaminant barriers provided by baseline Alternative 1. This
alternative would not meet the City's water quality goals with
respect to pathogen control during cold weather operation at
BRWTF, nor would it meet finished water TDS and sulfate goals.
Alternative 6: Carter Lake pipeline for turbidity, suspended solids,
manganese, taste and odor, organics, DBP, and inorganics control
followed by chlorine dioxide preoxidation for additional pathogen,
taste and odor, organics, and DBP control. This alternative meets
~aas2z z~o ES-6 osnaia~
~ BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
~ Executive Summary
all the City's water quality goals, and provides at least one barrier
for each contaminant category evaluated.
G. Non-Economic Performance of Water Delivery Alternatives
The relative pertormance of multi-barrier water delivery alternatives was
evaluated using the K-T~ decision analysis procedure. Each water delivery
alternative was ranked by its ability to satisfy the non-economic performance
criteria relative to all other altematives. The general approach taken in ranking
BRWTF water delivery alternatives against each criterion was that wherever
possible prevention of contamination during raw water delivery to BRWfF is a
superior strategy to subsequent treatment at BRWTF. This approach is
consistent with the century old paradigm for drinking water treatment, which is
based on treating the highest quality source water available with the simplest and
most robust treatment process train.
As shown in Table ES-1, non-economic performance scores for the
BRWTF alternatives evaluated in this study were clustered between 0.5 and 0.6
for all but Alternative 6, which had a pertormance score of 0.942.
Table ES-1
Non-Economic Pertortnance Scores~'~
Alternative 1 2 3 4 5 6
Performance Score 0.512 0.573 0.606 0.554 0.603 0.942
Performance scores are expressed on a 0 to 1 scale, with a
indicating better performance. higher value
The non-economic analysis pertormed here indicates that Alternative 6 is
the highest ranked BRWTF multi-barrier water delivery alternative, followed by
Alternatives 1 through 5 with non-economic pertormance scores that were
grouped in a substantially lower range. The sensitivity of this alternative ranking
to the criteria weights assigned was evaluated using the sensitivity analysis
iaaszz zio ES-7 osnaio~
BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Executive Summary
feature of the Criterium DecisionPlus~ software package used to perform
decision analysis calculations. The ranking of BRWTF multi-barrier water
delivery alternatives was not sensitive to the weight assigned to any criterion.
H. Cost Opinions
The relative economic merit of multi-barrier water delivery alternatives was
evaluated based on a life-cycle cost present value analysis that included capital,
operation and maintenance (O&M), and project financing costs. A common set
of unit process and O&M costs to each BRWTF multi-barrier water delivery
alternative. The Class 4 planning level cost opinions, typically accurate to within
+50 percent to -30 percent, presented here reflect use of standard engineering
practices and were prepared without the benefit of detailed engineering designs.
Table ES-2
Cost Opinions in Millions of Dollars
Alternative 1 2 3 4 5 6
Capital 0.0 2.4 21.9 13.2 13.6 21.1
Annua108M 0.17 0.21 0.86 0.42 0.32 0.19
Net Present Value 5.2 9.3 53.4 29.2 26.7 17.1
~'~Capital cost opinions include material and construction estimates for process equipment and
basins, any additional structures needed to house process equipment, electrical service,
instrumentation and control, site work, yard piping, and general contracting. Engineering,
legal, and administrative expenses were estimated to be 20 percent of the material and
construction cost subtotal. A contingency factor of 25 percent was applied to the material
and construction subtotal.
~Z~O&M included treatment chemical, other consumables such as UV tamp and ballast
replacement, GAC replacement, pumping and other energy costs, and scheduied
equipment maintenance. An average daily flow rate of 5 mgd was used to calculate
variable consumable and energy O&M costs.
~3~A 30-year life-cycle was assumed. Because the expected useful life of large diameter
subterranean transmission mains is considerably longer than 30 years, the residual value of
the Carter Lake Pipeline beyond this time was credited to the net present value cost opinion
for Altemative 6. Other common economic analysis parameters used include a 2007
baseline, an O&M inflation rate of 4 percent, a loan interest rate of 6 percent, and a present
worth factor of 4 percent.
144922210 E.S-8 06/18/07
BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Executive Summary
Preferred Water Delivery Alternative
Both pertormance and cost varies widely among the six BRWTF water
detivery alternatives evaluated. Considering source water quality information,
relative risk of source water contamination, regulatory requirements, City drinking
water quality goals, and operational flexibility 8&V be/ieves that Alternative 6,
complete source water containment from Carter Lake to BRWTF with chlorine
dioxide preoxidation, is the most desirab/e and preferred alternative. Although
Alternative 6 does not have the lowest net present value among those evaluated,
it has a number of compelling benefits that are not provided by the other
alternatives including:
• Of the BRWTF multi-barrier water delivery alternatives evaluated
here, Alternative 6 alone follows the century old paradigm of
drinking water treatment in that it treats the best available water
source with the simplest and most robust combination of
processes.
• Alternative 6 has the best non-economic pertormance by a wide
margin. This alternative satisfied 22 of 28 criteria evaluated as well
or better than the other alternatives.
• Afternative 6 is unique among those evaluated in that it alone
addresses the near and long term potential for continued
degradation of water quality in existing BRWTF sources due to
continued residential development, extensive agricultural land use,
and increasing recreational use. Although notable advances in
treatment technology have been made in recent years, contaminant
removal during drinking water treatment is still an imperfect
science. Thus, as has traditionally been the case, preventing
source water contamination provides a more robust barrier than
subsequent treatment as the first line of defense in protecting public
health.
• Other regionai drinking water providers also desire to use a
dedicated pipeline from Carter Lake for raw water delivery to their
facilities. Combining raw water conveyance to BRWTF with that of
other providers allows more efficient use of scarce regional water
resources.
iaas2z z~o ES-9 osnaio~
~ BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Executive Summary
a
. Full containment of raw water conveyance from Carter Lake to
BRWTF would provide additional flexibility in managing the City's
water resources portfolio. Other water delivery alternatives require
seasonal storage of raw water in Boulder Reservoir for use when
BFC in not in service. Year-round storage in Carter Lake would
remove the need to project annual seasonal storage required in
Boulder reservoir, and thus avoid the undesirable consequences
that result if seasonal Boulder Reservoir storage is substantially
overestimated.
• Conveyance of raw water through a Carter Lake pipeline would be
consistent with the City's historical policy of protecting source water
quality by providing full containment from its other water sources.
• Full containment from Carter Lake to BRWTF would provide a
much more uniform raw water quality, substantially simplifying
treatment optimization and increasing treatment process reliability.
• Alternative 6 is the only BRWTF water delivery approach that
provides at least one robust barrier for each contaminant category
considered in this study.
~aaszzz~o ES-10 osnaio~
BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Chapter 1- Introduction
Chapter 1
Introduction
This chapter describes the purpose, background, and approach of the
Integrated Evaluation of Boulder Reservoir Water Treatment Facility Source
Water Protection and Treatment Improvements study (Integrated Study). In
addition, this chapter briefly describes recent regulatory changes that may affect
drinking water treatment at the Boulder Reservoir Water Treatment Facility.
A. Purpose
The purpose of the Integrated Study is to evaluate source water protection
alternatives from the Source Water Quality Planning Study (Phase I Study) and
treatment alternatives from the Predesign Report for Near-Term Improvements
(Predesign Report) and develop a long-term plan for meeting regulatory and City
of Boulder (City) water quality goals at the Boulder Reservoir Water Treatment
Facility (BRWTF). Multi-barrier alternatives have been evaluated based on a set
of performance criteria developed by City staff, and consideration of life cycle
costs associated with each alternative.
The Integrated Study was performed within the context of an ongoing
effort by the City to establish definitive drinking water quality and quantity goals
as a framework for planning and implementing future improvements throughout
the City's drinking water system. One central strategy for achieving the City's
water quality goals is to implement a multi-barrier approach to protecting the
City's drinking water supply from both biological and chemical contaminants.
Barriers may include source water protection activities that either reduce or
prevent introduction of contaminants, or minimize their passage throughout the
drinking water system through treatment. A multi-barrier strategy to control
drinking water contaminants affords superior public health protection.
B. Project Background
Raw water is conveyed to BRWTF from Carter Lake through a 21-mile
long, open, earthen canal, referred to as the Boulder Feeder Canal (BFC), which
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~ BRWTF MULTI -BARRIEA APPROACH STUDY , RAW WATER SUPPLY ROU7
FIGURE
1-~
BRWTF INTEGRATED SOURCE WATER AND TRl=ATMENT STUDY
Chapter 9 - Introduction
uitimately discharges into Boulder Reservoir (Figure 1-1). Between April and
October, the City diverts raw water from BFC just upstream of Boulder Reservoir
and delivers it through a pipeline directly to BRWTF. During the remaining
months, when BFC is not in operation, raw water is pumped from Boulder
Reservoir to BRV1~F for treatment. Both BFC and BouldE~r Reservoir have
several features that make them vulnerable to source water quality degradation,
as listed in Table 1-1 and shown in Figures 1-2 and 1-3.
Table 1-1
Boulder Feeder Canal and Boulder Reservoir
Vulnerabilities to Water Quality Degradation
BFC Boulder Reservoir
• Open channel • Open to recreational uses including
• 51 outfalls discharge into BFC swimming and motorized boating
• 11 street crossings • Overland flow drainag~a
• Uncontrolled access • Naturally occurring m~nganese
• Neighboring land uses • Algal blooms leading to T&O episodes
• Herbicides routinely applied • Higher TDS due to mineral dissolution
• Bank scouring during storm events • High turbidity from wind action and BFC
flows
• Reduced treatability due to higher
temperature
In 2003, the Source Water Quality Protection Study (Phase 1 Study) was
completed by Black & Veatch (B&V) to identify and ev<~luate alternative
approaches to improve and protect source water quality for the BRWTF, based
on forecasted regulatory requirements as well as internal City-established goals.
It was recommended that the following alternatives be carried forward for further
investigation:
144922.210 ~ -2 06/18/07
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';~ _: ;
-:. ~
City of Boulder, Colorado - Multi-Barrier Approach Study
BLACK & VEATCH Figure
~ building ayyOrldof differe~ce~° ~ _2
Outfalls, Erosion, and Road Crossings on Boulder Feeder Canal
ENERGY WATER INFORMATION GOVEflNMENT
--.~ .~ :e - ~ ~ .~-
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BLACK & VEATCH City of Boulder, Colorado - Multi-Barrier Approach Study
~r buildingayyp~~dofdifference•° Figure
Outfalls and Stormwater Diversions to Boulder Feeder Canal 1-3
ENERGY WATER INFORMATIOM GOVERNMENT
BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Chapfer 1- Introducfion
Near-Term - Boulder Reservoir Management - Utilize Boulder Reservoir
as a year-round terminal reservoir rather than divert raw
water directly from the BFC. Raw water will then be pumped
from Boulder Reservoir to the BRWTF.
Long-Term - Pipeline from Carter Lake to the BRWTF - Construct a
21-mile raw water pipeline from Carter Lake that would
deliver water year-round to the BRWTF by gravity flow.
Since that time, the City has modified the intake structure at the Boulder
Reservoir to reduce the manganese load to the BRWTF. In addition, the City
recently participated with other drinking water providers in a study to further
explore the feasibility of a pipeline from Carter Lake to the BRWTF. The study
evaluated potential pipeline alignments and refined capital cost opinions for each
of the participants. However, some of the entities included in the study may not
participate in the pipeline, which would potentially increase the City's share of the
cost.
At the same time the Phase 1 Study was being developed, the Predesign
Report for Near-Term Improvements for the Boulder Reservoir Water Treatment
Plant (Predesign Report) was completed by MWH. This plan presented near-
term, mid-term and long-term recommendations for improvements at the
BRWTF. Near-term improvements were completed in 2005 and included the
installation of dissolved air flotation (DAF) facilities, baffling the clearwell, and
providing on-site residuals lagoons. Recommended mid-term and long-term
improvements included:
Mid-Term - Chlorine dioxide
Pre-sedimentation
Filter backwash water treatment
pH adjustment
Long-Term - Ultraviolet (U~ disinfection
Membranes
Ozone
Granular activated carbon (GAC) caps on existing filters
~aas22z~o 1-3 osnsio~
BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Chapter 1- lntroduction
The mid-term treatment process improvements listed above have not yet
been implemented, but the City has begun the budget planning process for their
addition at BRWTF. For the purposes of this assessment mid-term
improvements are assumed to be included in the BRWTF treatment process
train, and addition of long-term improvements was evaluated based on this
updated baseline treatment capability.
The City has requested that 8&V utilize the findings of the two previous
reports referenced above to develop a multiple-barrier approach that combines
the most cost effective means of ineeting the City's water quality and quantity
goals. This study is especially timely in light of the City Council's recent
endorsement of the development of an 11-mile recreational trail along the.BFC
from U.S. 36, southeast of Lyons, to the Boulder Reservoir. A city and county
staff team assessed the potential impacts of the trail and identified mitigation
measures through a community and environmental assessment process (CEAP).
The primary issue identified in the CEAP was the potential impacts of the
proposed trail on the City's drinking water supply for the BRWTF.
C. Regulatory Environment and City Water Quality Goals
The recently promulgated Long-Term 2 Enhanced Surface Water
Treatment Rule (LT2ESWTR) and City drinking water quality goals will influence
the development and evaluation of multi-barrier drinking water delivery
alternatives at BRWTF.
1. Regulatory Environment
The regulatory environment surrounding drinking water quality has
continuously evolved over the past 30 years, and will likely continue to do so in
the future. The most recent regulations that impact surface water treatment are
the Stage 2 Disinfectants and Disinfection Byproducts Rule (Stage 2 DBPR) and
Long-Term 2 Enhanced Surface Water Treatment Rule (LT2ESWTR),
promulgated on January 4, 2006 and January 5, 2006, respectively. Collectively,
these regulations balance the risk-risk tradeoff between health concerns related
to exposure to pathogenic microorganisms, particularly Cryptosporidium, and
disinfection byproducts formed in chlorinated drinking water. These regulations
will be progressively implemented over the next 5 to 7 years. Based on the
iaaszz zio 1-4 osnaio~
BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Chapter 1- Introduction
regulatory effort required to assess public risk, toxicity or infectivity, and
avoidance or treatment costs associated with emerging drinking water
contaminants, B&V believes that significant additional drinking water standards
related to pathogens, particulates, and disinfection byproducts are unlikely to be
promulgated until after implementation and initial compliance with the Stage 2
DBPR and LT2ES1/VrR are complete.
B&V believes that the most likely area in which new drinking water
standards could be promulgated during the next 10 years will be organic
micropollutants. Over the past 5 years there has been growing recognition and
concem regarding the health effects of endocrine disrupting compounds (EDCs),
pharmaceutically active compounds (PhACs), and personal care products
(PCPs) that enter drinking water supplies through municipal wastewater
discharges and non-point sources. Research into the occurrence, fate, and
health effects of a wide range of potential EDCs, PhACs, and PCPs is ongoing.
The United States Environmental Protection Agency (USEPA) has promulgated
an unregulated contaminant monitoring rule (UCMR) to evaluate the occurrence
of organic micropollutants in drinking water supplies. In addition, USEPA has
developed a repeating 5-year process to evaluate the need to regulate specific
micropollutants identified in Candidate Contaminant Lists (CCLs). Of 60
contaminants (50 chemicals and 10 microbes) identified in CCL1 (March 1998),
20 were classified as priorities for regulatory determination; however, 12 of these
were found to have insufficient information to support a regulatory determination.
None of the remaining 8 contaminants were recommended for regulation in the
final determinations announced in March 2003. CCL2, promulgated in
February 2005, identifies 9 microbes and 42 chemicals that are scheduled for
regulatory determination in 2010. Although USEPA has the authority to
promulgate new drinking water standards at any time, B&V believes it is unlikely
that additional regulations will be promulgated for any of these contaminants
before the regulatory determinations of CCL2 are finalized.
2. City Drinking Water Quality Goals
The City has established a set of drinking water quality goals and
operational treatment practices in order to ensure public health, minimize
distribution system deterioration, and provide uniformly high quality water to all its
~aassz.z~o 1-5 osnsio~
~ BRWTF INTECaRATED SOURCE WATER AND TREATMENT STUDY
t Chapter 1- lntroducfion
customers. Several of the City's drinking water quality goals are more stringent
than standards required by state and federal drinking water regulations
(Appendix 1), in some instances based on prudent concerns related to public
health and in others to enhance the palatability and uniformity of finished drinking
water. Specific City drinking water goals that exceed mandated regulatory
standards include turbidity (health), microbial pathogens (health), disinfection
byproducts (health), taste and odor (aesthetic), sodium (uniformity), sulfate
(uniformity), total dissolved solids (uniformity), fluoride (health), manganese
(aesthetic), and pH (deterioration). Because the City relies on two separate
facilities supplied with source waters of seasonally differing water quafity, there
are inherent operational challenges and potential cost implications associated
with meeting its drinking water quality goals, as discussed throughout this report.
D. Contaminant Barrier Requirements
The barrier requirements for BRWTF, based on current state and federal
regulatory requirements and City water quality goals, were identified through
review of source water quality data for Carter Lake, BFC, and operational data
from BRWTF. Barriers for microbial pathogens, disinfection byproducts (DBPs),
organic micro-poilutants, manganese, taste and odor, and inorganic contaminant
control were evaluated. The potential impacts of both long-term average water
quality and short-term acute contamination episodes were considered.
E. Multi-Barrier Alternatives Performance Evaluation
The relative performance of multi-barrier water delivery alternatives
developed in this study was evaluated using the Kepner-Tregoe~ (K-T~) decision
analysis procedure. K-T~ Decision Analysis is a systematic procedure that
encompasses the fundamental thought pattern people use to make choices. The
specific techniques that define the systematic procedure used in K-T~ Decision
Analysis expand a~d refine the elements of this thought pattern:
• We appreciate that there is a choice to be made.
. We consider the specific factors that should be satisfied for the
choice to succeed.
iaaszz zio 1-6 osnaio~
BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Chapter 1- Introducfion
. We decide what course of action best satisfies these factors.
. We consider the risks associated with the chosen course of action
that could jeopardize its success.
The following sections describe the nine steps that constitute the K-T~ Decision
Analysis process
1. State the Decision
The decision statement describes the "choice dilemma" that is to be
resolved in a decision-making process, indicates an intended result, and sets
limits on the choice being made. A decision statement is a short and concise
description of the choice to be made that includes a choice word (select, choose,
pick, etc.), an intended result, and one or iwo key modifiers that broaden or
narrow the range of the choice. The decision statement also specifies the level
at which the current choice is to be made based on implied prior decisions. The
decision statement for this project is:
"Select a multi-barrier water delivery approach for the BRWTF."
2. Develop the Objectives
The second step in K-T~ Decision Analysis is to develop decision
objectives, which consists of the set of criteria that will influence the decision.
This set of decision criteria forms a basis to help evaluate BRWTF water delivery
alternatives fairly. City staff developed criteria in five categories including
finished water quality, source water, treatment operations, risk, and
environmental and public acceptance, as outlined in Chapter 4.
3. Classify the Objectives into MUSTs and WANTs
Each of the criteria that form the set of decision objectives is classified
based on its role in the decision: those criteria that are mandatory for any
acceptable decision alternative are classified MUSTs, whereas those criteria that
are desirable for any acceptable decision alternative are classified as WANTs.
The set of decision criteria developed in Chapter 4 are also classified in that
chapter.
144922210 ~ -7 06/18/07
BRWTF 1NTEGRATED SOURCE WATER AND TREATMENT STUDY
Chapter 1- lntroducfion
4. Weigh the WANTs
The relative importance of WANT criteria in the decision at hand is
established by assigning numerical weights between 1 and 10 to each. City staff
assigned relative weights to the WANT decision criteria as described in
Chapter 6.
5. Generate Alternatives
Candidate solutions to the problem defined in the decision statement,
termed alternatives, are developed based on review of the decision criteria set,
regulatory requirements, industry standards, and decision group experience and
judgment. Conceptual improvements previously identified in the Phase 1 Study
and Pre-design Report, as well as those in the LT2ESWTR Microbial Toolbox
(Table 3-4), were reviewed for applicability to either source water conveyance to
or treatment at BRWT'F. Conceptual improvements that were determined to be
potentially feasible were grouped into candidate water delivery alternatives based
on meeting the barrier requirements identified in Chapter 3.
6. Screen the Alternatives through the MUSTs
Each alternative developed in step 5 is screen against the minimum set of
requirements defined by mandatory MUST criteria. Only those alternatives that
completely satisfy all MUST criteria are considered further in the decision
process. The BRWTF multi-barrier water delivery alternatives developed in
Chapter 5 satisfy the MUST criteria as classified in Chapter 4.
7. Compare the Alternatives Against the Wants
The performance of each decision alternative against the set of WANT
criteria is evaluated in comparison to all other alternatives to establish a relative
ranking of alternatives. The relative performance ranking of BRWTF water
delivery alternatives is described in Chapter 6.
8. Consider the Adverse Consequences
Adverse consequences associated with selection of each alternative are
identified and reviewed to understand the risks associated with each.
iaaszz.zio 1-8 osnaio~
BRWTF lNTEGRATED SOURCE WATER AND TREATMENT STUDY
Chapter 1- Introduction
9. Make the Best Balanced Decision
A balanced decision regarding the most appropriate alternative solution to
the decision statement requires collective consideration of relative alternative
ranking and potential adverse consequences of each alternative. For this study,
an economic evaluation of capital and operation and maintenance (O&M) costs
was also conducted, as described in Chapter 7. Both non-economic
pertormance and economic life-cycle value of BRWTF water delivery alternatives
were considered in selection of a recommended BRWTF water delivery
alternative, as described in Chapter 8.
144922210 1-9 osn eio~
BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Chapter 2- Sou~ce Water Quality
Chapter 2
Source Water Quality
This chapter provides a brief overview of the existing BRWTF source
water system and its historical operation. An evaluation of water quality for the
potential sources that could be used to supply BRWT'F, including Carter Lake,
BFC, and Boulder Reservoir, is also provided. The quality of raw water delivered
to BRWTF by the BFC and Boulder Reservoir systems was evaluated for their
current configurations with no additional source water protection features added,
and with full containment from Carter Lake to BRWTF as recommended in the
Phase I Source Water Protection Study.
A. Existing BRWTF Source Water System
Historically, operation of BRWTF has ultimately relied on delivering raw
water through BFC, either directly to BRWTF or to Boulder Reservoir for
subsequent use. During canal operation, raw water is typically diverted from
BFC at a location upstream of Boulder Reservoir and delivered through a
pipeline to BRWTF for treatment and distribution. Any remaining flow continues
in BFC for a short distance and discharges to Boulder Reservoir where it is
stored for water exchanges, downstream irrigation or as a reserve raw water
supply for treatment at BRWTF. When the canal is not in operation, raw water is
pumped from Boulder Reservoir to BRWTF.
7. Boulder Feeder Canal
The open channel BFC generally follows a north to south route traversing
the lower slopes of the foothills. As such, it tends to capture a significant amount
of surface runoff that originates uphill and to the west. Although a riparian habitat
along the canal could, to some extent, naturally attenuate contamination, the
channel bottom and banks are regularly maintained by Northern Colorado Water
Conservancy District (NCWCD) to prevent growth of vegetation. Therefore,
although the raw water at its source in Carter Lake is of a very high quality,
significant degradation generaily occurs as the water travels the length of the
BFC.
iaaszz zio 2-1 osnaio~
BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Chapter 2- Source Water Quality
The resulting variable water quality delivered to BRWTF and/or Boulder
Reservoir can pose significant treatment challenges to the City. The BRWTF
staff must frequently adjust treatment operations in response to raw water quality
changes due to weather and human or animal activities. Unfortunately, existing
BRWTF monitoring and treatment technologies have not always provided the
ability to respond quickly enough to rapid water quality changes and there have
been occasions when the facility has been taken off-line to avoid the possibility of
violating treated water quality standards. Operational changes in treatment are
also required each time the raw water supply is switched between BFC and
Boulder Reservoir.
2. Boulder Reservoir
Boulder Reservoir is a low volume, shallow, Class 1 warm water fishery
owned by the City of Boulder and operated by NCWCD. The reservoir has a
surface area of approximately 700 acres and a capacity of about 13,270 acre-
feet (ac-ft). Historically, BRWTF has primarily used the Boulder Reservoir supply
only during the winter months when BFC is not in service. Water from Boulder
Reservoir must be delivered by pumping from RWTF Raw Water Pumping
Station.
Boulder Reservoir is a multipurpose reservoir that is used year round for a
variety of recreational activities including special events that bring in large
numbers of people for short durations. As a result, the reservoir is subject to
water quality degradation resulting from both body contact recreation and non-
body recreational activities such as fishing and boating. These activities
contribute to general water quality degradation and an increase in BRWfF raw
water supply contaminant load.
Flows from BFC have in the past been as high as 2.5 times the reservoir
volume. These flows are significant in that high flows tend to improve water
quality by keeping the reservoir water mixed and fresh, which helps reduce
stratification that occurs in the summer. However, the City has no control over
these flows, which can vary significantly from year-to-year. In addition, the
reservoir provides a degree of dilution, settling, and natural processes to break
down contaminants before raw water reaches BRWTF.
~aaszz.z~o 2-2 osnaio~
BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Chaptei 2- Source Water Quality
During the late summer, natural temperature stratification occurs in the
reservoir and a hypolimnetic layer low in dissolved oxygen forms in the deeper
regions of the reservoir. This condition results in the release of soluble
manganese from reservoir sediment into the water column and causes taste and
odor treatment concerns at BRWTF.
The water in the reservoir has higher total dissolved solids (TDS) including
sodium, sulfate, and hardness compared with water entering from BFC. Turbidity
in the reservoir is typically less than 10 nephelometric turbidity units (NTU), but
wind action and high canal flows can increase turbidity to as high as 150 NTU.
Additional water quality concerns include objectionable tastes and odors, which
may be a byproduct of hypolimnetic anoxia.
B. Water Quality Data Sources
Source water quality data for Carter Lake, BFC, and Boulder Reservoir
were reviewed. Water quality data were collected from previous reports
prepared for the City as well as supplemental data supplied by the City. Data
obtained from USEPA and United States Geologic Survey (USGS) online
databases were also reviewed. Table 2-1 lists source water data reviewed for
this study. Not all analyses cover the entire sampling period or all three source
waters.
C. Source Water Quality Data Summary
Water quality data reviewed for this study were evaluated for both spatial
and temporal coverage of the associated source waters. Table 2-2 lists the
average water quality data for each raw water source and the following sections
provide a summary of the data evaluation by source water.
1. Carter Lake
Carter Lake is a relatively deep (140 feet) upland reservoir. Upland
reservoirs receive imported water by utilizing hydraulic structures and typically
very small runoff areas. Carter Lake is surrounded by Bureau of Land
Management lands and has no natural tributaries. The lake is open to motorized
boating, but has historically had excellent water quality with only slight seasonal
variations.
taaszzz~o 2-3 osnaio~
BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Chapter 2- Source Water Quality
Table 2-1
Water Quality Data Sources
Parameter Data Source Time Period
Microbiological
Giardia, Crypto, FC Phase I Study Pre 2004
Giardia, Crypto Predesign Report 1992-2000
Giardia, Crypto, TC, FC, HPC Water Treatment Evaluation Study Pre 1999
Giardia, Crypto, FC Boulder Reservoir WTP Assessment 1994-2000
Giardia, Crypto, TC, FC, EC City of Boulde t995-2005
Giardia, Crypto BFC Proposed Trail Study 1997-2000
TC, FC, EC, FS USGS National Water Information System 1970-2004
Physical Parameters
pH, turbidity, temperature, DO, SC Phase I Study Pre 2004
pH, turbidity, temperature, DO, SC Predesign Report 1992-2000
pH, turbidity, color, odor Water Treatment Evaluation Study Pre 1999
pH, turbidity, temperature, DO, SC Boulder Reservoir WTP Assessment 1994-2000
pH, temperature, DO, SC USGS Water-Resources Report 99-4091 1997-1998
pH, turbidity, temperature, DO, SC, true
color, ORP, flow
City of Boulder
1995-2005
pH, transparency, temperature, DO, SC USGS National Water Information System 1970-2004
Chemical Paremeters
Cations, anions, alkalinity, Fe, Mn Phase I Study Pre 2004
Cations, anions, alkalinity, Fe, Mn Predesign Report 1992-2000
Cations, anions, alkalinity, metals Water Treatment Evaluation Study Pre 1999
Cations, anions, alkalinity, Fe, Mn Boulder Reservoir WTP Assessment 1994-2000
Fe, Mn, Se, U, N, P, trace metals USGS Water-Resources Report 99-4091 1997-1998
Cations, anions, alkalinity, Fe, Mn, P,
N03 , NOZ
City of Boulder
1995-2005
Cations, anions, alkalinity, metals USGS National Water Information System 1970-2004
taaszz zio 2-4 osnaio~
BRWTF 1NTEGRATED SOURCE WATER AND TREATMENT STUQY
Chapfer 2- Source Water Quality
Table 2-1
Water Quality DaW Sources (continued)
Parameter Data Source Time Period
Organic Parameters
Chlorophyll a, TOC, UVA254 Phase I Study Pre 2004
Chlorophyll a, TOC, SUVA Predesign Report 1992-2000
TOC, DBPS Water 7reatment Evaluation Study Pre 1999
Chlorophyll a, TOC, UVAZSa Boulder Reservoir WTP Assessment 1994-2000
Chlorophyll a, TOC, UVA254 City of Boulder 1995-2005
Chlorophyll a/b, TOC USGS National Water Information System 1970-2004
TOC Bureau of Reclamation 2005
Abbreviations:
DBPS - disinfection byproducts, DO - dissolved oxygen, EC - Escherichia coli, FC - fecal coliforms,
FS - fecal streptococci, HPC - heterotrophic plate count, ORP - oxidation-reduction potential,
SC - specific conductance, SUVA - specific ultraviolet absorbance (UVAz54ITOC), TC - total coliforms,
TOC - total organic carbon, UVAzs4 - ultraviolet absorbance at 254 nm.
~'~Source Water Quality Pfanning Study, Bfack & Veatch, April 2003.
~Z~Predesign Report for Near-Term Improvements for the Bouider Reservoir Water Treatment Plant,
MWH, June 20, 2003.
~3~Water Treatment Plant Evaluation Study (WTPS - Erie, CO), HDR Engineering Inc., February 2006.
~a~Assessment of the Boulder Reservoir Water Treatment Plant, McGuire Environmental Consultants
Inc., May 2001.
~S~City of Boulder Drinking Water Program, various data provided by the City of Boulder
~6~Assessment of Pathogen Risk of a Proposed Trail on the Boulder Feeder Canal (BFC), Boulder
County Colorado, CH Diagnostic & Consulting Service, Inc., October 10, 2000.
~'~United States Geological Survey, National Water Information System: USGS 06742500 Carter Lake
near Berthoud, CO, htto://nwis.waterdata.usos.aov/usa/, accessed June 09, 2006.
~e~Water-Quality Conditions, Hydrologic Budget, and Sources and Fate of Selected Trace Elements and
Nutrients in Boulder Reservoir, Boulder, Colorado, 1997-98. USGS Water-Resources Investigations
Report 99-4091.
~9~Northern Colorado Water Conservancy Database, Bureau of Reclamation - Carter Lake Station CL-
DAM1, 2005.
144922.210 2-~J O6/18/07
BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Chapter 2- Source Water Quality
Table 2-2
Averege Water Quality Data for Carter Lake,
Boulder Feeder Canal, and Boulder Reservoir
Water Quality Paremeter Carter Lake Boulder Feeder Canal Boulder Reservoi
Monitoring Period 1970-2005 1997-2005 1997-2005
Temperature (°C) 10.2 11.5 14.2/16.8
pH (s.u.) 7.6 8.2 7.6/82
DO (mg/L) 7.9 10.1 4.9/82
Turbidity (NTU) N/A 5.4 25/9
Specific conductance (Nmho/cm) 71 109 284/295
Total dissolved solids (mg/L) 43 66 172/180
Total suspended solids (mg/L) N/A 7 18/6
Secchi depth (m) 2.6 N/A 1.3
Hardness (mg/L as CaC03) 40 48 120/122
Alkalinity (mg/L as CaC03) 31 39 66/66
Sodium (mg/L) 2.2 3.4 10.3/9.6
Sulfate (mg/L) 3 14 77/78
Iron, dissolved (Ng/L) 9 10 4/3
Manganese, dissolved (Ng/L) 3 < 10 88/8
Phosphorous, dissolved (Ng/L) 12 15 22/14
Nitrate + nitrite (mg/L) 0.07 0.03 0.02/0.01
Total organic carbon (mg/L) 3.6 3.5 3.5/3.6
Chlorophyll a(µg/L) 1.4 N/A 3.9
E. coli (CFU/100 mL) 1 66 58/8
Fecal coliform (CFU/100 mL) < 1 38 20/7
Giardia (cysts/L) ND 0.32 to 0.49 < 0.001
Cryptospondium (oocysts/L) ND 0.02 to 0.16 0.01
~'~Samples collected from Carter Lake when ice cover was not present.
~z~Samples collected during periods of canai operation only, typically April through October.
"~Samples collected 0.5 m above the bottom/composite epilimnion samples.
~"~TDS = 0.61 xSpecific conductance
N/A- Not available.
ND - Not detected.
~aaszz 2to 2-6 osnaio~
BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Chapter 2- Source Water Quality
a. Microbial Characteristics
The microbial quality of Carter Lake has historically been excellent, due in
large part to its location, small runoff area, and limited human impact. Sample
data for total coliforms, fecal coliforms, E. coli, and fecal streptococci are
consistent with surface water that is minimally impacted by human and animal
wastes. The following summarizes the historic microbial quality of Carter Lake.
• Fecal coliform measurements collected between 1970 and 2001
averaged less than 1 colony forming unit per 100 milliliters
(CFU/100 mL), with a maximum concentration of 17 CFU/100 mL.
Only three percent of the samples reviewed had concentrations
greater than 1 CFU/mL.
• All E. coli monitoring results reviewed between 2001 and 2004
were less than or equal to 1 CFU/100 mL.
• No data on protozoan levels in Carter Lake was reviewed; however,
between 1998 and 2003, neither Giardia nor Cryptosporidium was
detected in raw water conveyed through a pipeline from Carter
Lake to the City of Erie, Colorado.
b. Physical Characteristics
Physical water quality parameters in Carter Lake are typical of relatively
deep lakes with small catchments, as summarized below.
• Raw water pH is neutral to slightly alkaline.
• Turbidity and specific conductance are low.
• The average temperature of water in Carter Lake between 1970
and 2004 was 10.2 degrees Celsius (°C), with maximum and
minimum recorded values of 24°C and 0.5°C, respectively.
Temperature stratification with depth was observed in summer
months, with seasonal overturn events in the spring and fall.
• Dissolved oxygen in the hypolimnion is below saturation during
summer months; however, generally remains above 3 milligrams
per liter (mg/L).
~aaszzz~o 2-7 osnaio~
BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Chapter 2- Source Water Quality
c. Chemical Characteristics
The following provides a summary of the chemical characteristics of
Carter Lake.
• Carter Lake displays chemical characteristics consistent with highly
pristine mountain waters derived primarily from snowmelt including
low alkalinity, hardness, and TDS. Figure 2-1 shows TDS and
sulfate concentrations for the period 1970 to 2004.
• Because Carter Lake is situated in an area with low mineral content
soils, there is little opportunity for metals uptake into the water
column.
. Both iron and manganese concentrations have been continuously
below EPA's Secondary Maximum Contaminant Levels (SMCLs) of
0.3 mg/L and 0.05 mg/L, respectively for data reviewed between
1973 and 2004.
• The productivity of Carter Lake is classified as oligotrophic based
on Secchi depth, chlorophyll a, and total phosphorous
concentrations. TOC concentrations average 3.5 mg/L and vary
little with season. Based on these considerations the potential for
serious taste and odor problems related to algal blooms in Carter
Lake is low.
2. Boulder Feeder Canal
The BFC is bordered by a variety of public and private.lands that have
agricultural, industrial, residential, and recreational usages. Because of its open
construction, BFC experiences surface runoff and has 51 outfalls and 11 street
crossings along its length. Therefore, although water quality in Carter Lake has
historically been excellent, significant degradation typically occurs as water flows
through BFC.
a. Microbial Characteristics
The City of Boulder Drinking Water Program has conducted extensive
reconnaissance of water quality in the BFC in recent years, particularly related to
microbial degradation. Data collected between 1995 and 2005 were reviewed
ianszzz~o 2-8 osnaia~
125
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~
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~ TDS -~ Sulfate
BLACK & VEATCH City of Boulder, Colorado - Multi-Barrier Approach Study
~a 6oildiogaW01'~I~ofdiNerence~•
Total Dissolved Solids and Sulfate in Carter Lake
ENERGV WATFfl INFOflMAT10N GOVERNMENT
Figure
2-1
100
75
50
25
National Secondarv Drinkinq Water Standards
Sulfate: 250 mglL
COB Drinking Water TDS Goal TDS: 500 mg/L
' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' . . . ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' _ '
' ~ ' ' ' ' ' ' ' ' ' . ' ' ' ' ' ' ' ' ' ' ' . ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' ' _ ' ' ' ' _ '
0
07168 07I70 07172 07/74 07176 07178 07180 07182 07184 07/86 07/88 07190 07192 07/94 07196 07198 07/00 07/02 07/04 07/06
BRWTF 1NTEGRATED SOURCE WATER AND TREATMENT STUDY
Chapter 2- Source Water Quality
and yearly baseline fecal coliform contamination values were calculated after
excluding anomalously high values associated with acute contamination events.
Fecal contamination in BFC appears to be increasing with time, as shown
graphically on Figure 2-2. Both average monthly (June through October) and
maximum monthly fecal coliform concentrations increased over the time period
examined. Because the trends represented by these data do not include acute
contamination events, they represent a conservative estimate of fecal
contamination in BFC.
Review of extensive bacteriological reconnaissance monitoring data
collected during the 1995 through 2005 BFC operating seasons reveal the
following:
• E. coli and fecal coliform levels were measured at multiple locations
along BFC, with a total of 307 E. coli measurements collected on
78 days during the 2002 through 2005 canal operating seasons and
a total of 328 fecal coliform measurements collected on 89 days
during the 1995 through 2003 canal operating seasons,
respectively. Samples were not collected at all locations on every
sample date. The cumulative frequencies of bacterial
contamination in BFC based on this data are given in Figure 2-3.
• Bacterial water quality varies spatially along the length of BFC, with
higher levels of degradation frequently occurring downstream, as
shown in Figure 2-4.
. Bacterial water quality varies temporally in BFC, with positive
correlation between canal flow and rainfall and contamination.
Figure 2-5 illustrates the magnitude of an elevated E. coli
contamination episode in BFC captured in July 2005.
• The bacterial quality of water delivered by BFC to BRWTF is
significantly degraded compared with that of the original Carter
Lake source water. E. coli and fecal coliforms are typically present
in BFC water at the BRWTF intake in concentrations of tens to
thousands of CFU/100mL and tens to hundreds of CFU/100 mL,
respectively, compared to concentrations typically less than
1 CFU/100 mL in Carter Lake.
144922.210 2-9 D6/18/07
160
^ Average Month (June through October)
140
^ Maxi mum Month (June through October)
- ~
~ 120
~
0
0
~ 100
~
~
v
...
~ 80
L
Q
V 60
~
~
~ 40
20
0
1997 1998 1999 2000 2001 2002 2003
Year
City of Boulder, Colorado - Multi-Barrier Approach Study
BLACK & VEATCH Fi
gure
~ buildinq ayyOrldot difference°~
2'2
Historical Fecal Coliform Concentrations in BFC
ENFRGY WATER INfOR~dATiUN GOVEHNMENI
1.0
o.s
o.e
T 0.7
c~
c
m
Q 0.6
~
j 0.5
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ia
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7
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_ - ~~q-O~° °
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_ ;
~
~
~
~
~
~
~
~ ~
~
CDPHE Drinking Water Supply
Classification Standard
0.0 ~
0
500 1000 1500
E.coli (CFU/100mL)
2000 2500
3000
~ O E. coli: 2002 -- 2005 ~ Fecal coliforms: 7995 -- 2003 ~
Q a~cK & vEarct~
~ buildinq ayyOC~duf differenoe~
ENEH6Y WATEN INfUNMAT~ON G~VEPNMENt
City of Bouider, Colorado - Multi-Barrier Approach Study
Cumulative Frequency of Bacterial Contamination in BFC
Figure
2-3
1000
900
800
700
J
~ 600
0
0
~
~ 500
0
v 400
LLi
300
200
100
0
/~ I CDPHE Drinking Water
/ ~ Classification Standard
------------- -------- ---------------------------------/--- ---------_.
Lyons St. Vrain Rd Nelson Rd Prospect Rd Oxford Rd Niwot Rd Boulder
Reservoir
BFC Location
-~-5M9/2003 -~k-5/29/2003 f6/5/2003 ~6/12/2003 --F-6/19/2003 ~~7/15/2003
BI.ACK & VEATCH City of Boulder, Colorado - Multi-Barrier Approach Study
Qa 6uildingayyqr~~ofdiHerence^ F19U1'@
Elevated E, coli Contamination Enisodes in BFC - Spatial Variation 2"4
ENEN6Y WATEN INF~RM0.T10N G6VERNMENT ~
3000
2500
2000
J
~
O
O
~
~ 7500
O
V
W
7000
500
~ CDPHE Drinking Water
Classification Standard
----•---------~-----------------------•-------•-------------------•---
0
07/02/OS
~-- yI Geometric Mean:
/ ~ 06/03/2005 to 07/06/2005
/ '
-•..l •--•-•••••---••---•--- ••• -• ----•-••--•-
BLACK & VEATCH
~. buildin98WOfIllofdiHerencea
ENEpGV WATER fNiOqMAT10N ROVEPNMENT
07/03/OS 07/04/05 07/OS/05 07/06/05
Date
-~ BFC at BRWTF Intake
City of Boulder, Colorado - Multi-Barrier Approach Study
Elevated E. coli Contamination Episodes in BFC -Temporal Variation
07/07/05
Figure
2-5
BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Chapter 2- Source Water Quality
These data highlight the potential for microbial contamination of BFC water
through surtace runoff, ouffalls, and scouring of the canal banks.
Extensive reconnaissance for protozoan contamination in BFC has also
been conducted over the past decade. The following summarizes these findings.
• Giardia has been regularly detected in BFC samples at an average
concentration between 0.32 and 0.49 cysts per liter (cysts/L), with
positive occurrence in 68 percent of samples. The maximum
Giardia concentration detected between 1994 and 2004 was
2.00 cysts/L.
• Cryptosporidium has frequently been detected in BFC samples at
an average concentration between 0.02 oocysts per liter
(oocysts/L) and 0.16 oocysts/L, with a maximum reported
concentration of 3.04 oocysts/L.
. The frequency of Cryptosporidium detection was lower than that of
Giardia, with positive occurrence in between 11 and 23 percent of
BFC samples.
• Monte Carlo simulation was used to predict probable
Crypfosporidium concentrations in BFC resulting from various
levels of recreational trail usage along BFC as a function of canal
flowrate. Results from these simulations indicated potential for
significant degradation in BFC water quality due to Cryptosporidium
contamination from adjacent recreational use.
b. Physical Characteristics
Physical water quality parameters in BFC are similar to those of Carter
Lake, with slight increases in temperature, pH, and dissolved oxygen.
c. Chemical Characteristics
Chemical water quality of BFC was also similar to that of Carter Lake, with
only marginally higher average mineral content, although short-term seasonal
increases in TDS and sulfate do occur, as shown in Figure 2-6. TOC at the
BRWfF intake on BFC is similar to that in Carter Lake.
~aaszz.2m 2-10 osnaio~
500
400
J
~ 300
m
R
w
7
H
Q 200
F-
100
------------------~~----------------------~-----...----------------...-----~----~------~--------------
~ NSDW TDS Standard
~ NSDW Sulfate Standard
" " '" " "....."'"'"" " " '...'""......
~
~ COB Drinking WaterTDS Goal
II --•-••••-----•••••••.~--•••••---
COB Drinking Water Sulfate Goal
. ..--~---•J~~~
••----•••••---•••f•••F----••••---••••• i---•~••••---•••-
-•••••-.'-,,.v---••~••-•---•-
0 ~
07/96
07/97 07198 07/99 07/00 07/01 07/02 07/03 07/04 07105 07106
Date
~ TDS -~ Sulfate
City of Boulder, Colorado - Multi-Barrier Approach Study
BI.ACK & V~A7CH Figure
building ayyp~~(~of difference-
~ Total Dissolved Solids and Sulfate in BFC 2"s
ENEftGY WATEB INFUflMATIUN EOVERNMENT
BRWTF INTECaRATED SOURCE WATER AND TREATMENT STUDY
Chapter 2- Source Water Quality
3. Boulder Reservoir
Boulder Reservoir is located atop mineralized soils that have relatively
high native sulfate and manganese. There are two natural tributaries and several
ditches that drain into Bouider Reservoir, increasing the nutrient loading and
potentially introducing contaminants. Boulder Reservoir is also used year-round
for a variety of recreational purposes including fishing, boating, and swimming,
which can also contribute to pathogen and contaminant loading.
a. Microbial Characteristics
The microbial water quality of Boulder Reservoir is vulnerable to pathogen
contamination due to operation of Boulder Feeder Canal. The following
summarizes the bacterial characteristics of Boulder Reservoir.
• Sampling of Boulder Reservoir by City staff demonstrates a causa{
link between fecal contamination in the reservoir and operation of
BFC. Fecal coliforms are present at or below the detection limit
during the months when BFC is not in operation. However, during
the months that BFC is in operation fecal coliforms are typically
present at measurable concentrations.
• Both E. coli and fecal coliform concentrations in the hypolimnion
(0.5 meters above the bottom of the reservoir) are slightly less than
their respective average concentrations in BFC.
• Fecal contamination in Boulder Reservoir appears to be increasing
with time, as shown graphically on Figure 2-7, based on both
seasonal and maximum monthly average fecal coliform data.
Samples collected from the hypolimnion between 1997 and 2003
show similar increasing trends as previously described for BFC
over the same time period.
• Although fecal contamination of Boulder Reservoir through surface
tributaries and recreational use have been documented, the
relatively low tributary flows (roughly eight percent of BFC flow) and
vertical stratification during warm weather months of BFC operation
make it unlikely that these contaminant sources account for
elevated fecal coliform levels in the reservoir hypolimnion.
iaaszz z~o 2-11 osnaio~
160
140
J 12O
E
0
0
~ 100
~
~
~
.~
~ 80
L
~
~
~ 60
~
V
~ 40
20
0
~Average Month (June through October)
^ Maximum Month (June through October)
1997 1998 1999 2000 2001 2002 2003
Year
BLACK & VEATCH City of Boulder, Colorado - Multi-Barrier Approach Study
~, buildi~g aWOf~(~ot diHerence~•
Historical Fecal Coliform Concentrations in Boulder Reservoir Hypolimnion
ENEAGV WATER INFOHMATION GOVERNMENT
Figure
2-7
~ BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
~ Chapter 2- Source Water Quality
Protozoan contamination has been detected less frequently and at lower
concentrations than in BFC. The following summarizes the protozoan
characteristics of Boulder Reservoir.
• Giardia was detected in 8 percent of samples collected from
Boulder Reservoir between 1997 and 2004, ~vith a maximum
concentration of 0.3 cysts/L. Cryptosporidium was not detected in
these samples. However, Crypfosporidium was reported at an
8 percent incidence rate in earlier sampling vvith a maximum
concentration of 0.2 oocysts/L.
• Dilution and natural attenuation processes that occur in the
reservoir likely contribute to the lower protozoan detection rate
compared with BFC.
b. Physical Characteristics
Physical water quality parameters in Boulder Reservoir are moderately
different than those of Carter Lake and BFC; with similar pH, lower dissolved
oxygen, and higher temperature, turbidity, total dissolved solids, and specific
conductance (Table 2-2). Secchi depth is lower than in Carter Lake indicating
reduced water clarity. Seasonal variation in physical water quality is observed as
discussed below.
c. Chemical Characteristics
Chemical water quality in Boulder Reservoir is degraded compared to
Carter Lake and BFC. The following summarizes chemical water quality in
Boulder Reservoir.
• Dissolution of naturally occurring mineral deposits in Boulder
Reservoir sediments leads to dramatically increased TDS,
hardness, alkalinity, sodium, sulfate, and manganE;se (Table 2-2).
• TDS and sulfate concentrations in Boulder Reservoir vary with
season, generally decreasing when BFC is in service and
increasing when BFC is not in service, as shown on Figure 2-8.
iaaszz.zio 2-12 os~is~o~
500 ------------------•-•---------~_
--- ------------------~..-----...--------------------------------~-•--•-
~ NSDW TDS Standard
400
J
`
~
~ 300
-- NSDW Sulfate Standard
d
r
~
~
N
N 200
~
H
•
COB Drinking Water TDS Goal
100 -----._.. .. . ---.. .. --- - ----- -- ••- --------------------- ------•-------
~ ` ~~
~ COB Drinking Water Sulfate Goal
• . - - - - - . .
- - . - .
0
07/96 07/97 07/98 07/99 07/00 07/D1 07/02 07103 07/04 07105 07106
Date
~- TDS ~ Sulfate
City of Boulder, Colorado - Multi-Barrier Approach Study
BLACK & VEATCH Fi
gure
building aVyp~~dof di~ference°
'
2"$
Total Dissolved Solids and Sulfate in Boulder Reservoir
ENERGr ',":nrcR INf~ONh~n7'~Oe~ ~,'7VERNMEN7
- BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
~
Chapter 2- Source Water Quality
• The productivity of Boulder Reservoir is classified as mesotrophic,
based on the lower Secchi depth, higher chlorophyll a, and higher
total phosphorous concentrations compared to Carter Lake. Based
on these considerations the potential for serious taste and odor
problems related to algal blooms in Boulder Reservoir is moderate.
TOC in Boulder Reservoir is similar to that in BFC and Carter Lake.
d. Seasonal Water Quality Variation
Physical and chemical water quality in Boulder Reservoir follows a repeating
seasonal pattern that results in vertical stratification in the water column, impacting
treatability at BRWTF when operation is from the reservoir intake. Vertical
stratification in Boulder Reservoir is reinforced by inflow from E3FC that is lower in
temperature than either the epilimnion or hypolimnion year-round. During the
summer months when reservoir water temperature increases, the hypolimnion
becomes anaerobic, and manganese is mobilized from native sediments.
Manganese mobilization is generally followed by a dramatic decrease in sulfate
concentration throughout the summer and fall, as illustrated on Figure 2-9. Sulfate
concentration is re-established throughout the water column in the winter when
biological activity is reduced.
Comparison of the water temperatures in BFC at BRWTF and the epilimnion
(surface layer) of Boulder Reservoir indicate that water enteriny the reservoir from
BFC is consistently cooler than the surrounding reservoir, as shown on
Figure 2-10. The higher bacterial contaminant concentrations in the hypolimnion of
Boulder Reservoir may be attributed to the settling of the cooler, and thus denser,
BFC water into the hypolimnion. This can cause short-circuiting of much of the
reservoir volume, resulting in a reduced mixing and dilution volume. Because the
reservoir intake for BRWTF is located in the hypolimnion, short-circuiting of
potentially pathogen loaded BFC water is particularly undesirable. Further studies
are necessary to quantify the extent of short-circuiting.
The seasonal variation in hypolimnion water quality is characteristic of
microbially mediated activity. Heterotrophic bacteria couple the oxidation of
organic matter with the reduction of inorganic terminal electron acceptors to gain
energy for metabolism. Bacteria preferentially exploit electron acceptors in order
of greatest energy generation, resulting in a temporal sequence of utilization
iaaszz.z,o 2-13 os~,sio~
1
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07l96 07/97 07/98 07/99 O7/00 07/01 07/02 07/03 07104 07/05
Date
--~- Dissolved Oxygen Sulfate -~ Manganese
City of Boulder, Colorado - Multi-Barrier Approach Study
BLACK & VEATCH Fi
g ure
r building aWO~ldof diifierence~~ Effect of Thermal Stratification on Dissolved Oxygen, Manganese, 2 _g
EN~R~Y WATER INFORMATION GOVERNMENT and Sulfate Concentrations in Boulder Reservoir Hypolimnion
30
25
,, ~ ~.
I ~~;_
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~ ~ ~
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07/96 07/97 07/98 07/99 07lUO 07/01 07102 07/03 07/04 07l05
Date
-•- Boulder Feeder Canal -~ Reservoir Hypolimnion Reservoir Epilimnion
BLACK & VEATCH City of Boulder, Colorado - Multi-Barrier Approach Study
Qr buildingayyOrlaotdifference° Figure
Water Temperatures in BFC and Boulder Reservoir 2-10
ENERGY WATER INFUR~AATiON GOVERNMENI~
BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Chapter 2- Source Water Qualrfy
(Figure 2-11). The sequence of oxygen depletion followed by Mn(II) production
and ultimately sulfate reduction observed in the hypolimnion of Boulder Reservoir
is consistent with microbial activity based on low iron and nitrate concentrations.
Variation in physical water quality parameters also supports seasonal
stratification in Boulder Reservoir. Lower temperature, pH, and dissolved
oxygen, as well as higher turbidity and suspended solids, are all indicative of
stratification. However, several key chemical constituents including hardness,
alkalinity, total dissolved solids, total organic carbon, and sulfate remain relatively
constant with reservoir depth. A scenario that mechanistically explains this
apparent inconsistency may be related to a thermally generated density gradient
as BFC water flows into Boulder Reservoir, as illustrated on Figure 2-12.
In this scenario, BFC water entering Boulder Reservoir sinks to the bottom
due to its lower temperature and higher density, where dissolved oxygen is
depleted by microbial respiration. As anaerobic water flows away from the BFC
inlet in the hypolimnion, manganese dioxide (MnOZ) in bottom sediment is first
microbially reduced releasing soluble manganese (Mn2+), followed by sulfate
reduction. Dissolution of other soluble minerals in bottom sediment also occurs,
increasing TDS. Inflow of water to the hypolimnion from BFC is balance by
withdrawal for BRWTF treatment and upwelling to the epilimnion. At the
interface between the hypolimnion and epilimnion soluble Mn2+ is oxidized by
molecular oxygen, re-precipitating particulate Mn02 that settles back into the
hypolimnion. Thus, mixing from below maintains anaerobic conditions in the
hypolimnion, while promoting othenrvise somewhat similar chemical water quality
throughout the water column.
D. BRWTF Operational Data
Operational water quality data for BRWTF provided by the City was
reviewed with respect to the treatment barriers currently in place for microbial,
disinfection byproduct, organic contaminant, manganese, taste and odor, and
inorganic contaminant control. Data for the years 1997 through 2005 indicate
that finished water from BRWTF generally meets all current Primary and
Secondary National Drinking Water Standards. However, several aspects of
finished water quality that may impact the decision on whether or not to
144922.210 2-14 06/18/07
organic
carbon
E;n~~r.r~ y
BLACK & VEATCH City of Boulder, Colorado - Multi-Barrier Approach Study
~, building aWO~Idof difference~° Figure
Microbial Energy Generation through Preferential Respiration with 2-11
EhE~,Y t~~A,~p ~~~FOH~:~A, o~, ~~~~~H~:,.,EN, Inorganic Terminal Electron Acceptors
Downstream
Demand
BFC
Epilimnion
BRWTP
BLACK & VEATCH
y buildingaW~~~dafdifference'°
ENERGY INATER INFORMRTION GOVENNNIEN7
Hypolimnion
City of Boulder, Colorado - Multi-Barrier Approach Study
Hydraulics of Thermally Generated Vertical Stratification
in Boulder Reservoir
Figure
2-12
BRWTF 1NTEGRATED SOURCE WATER AND TREATMENT STUDY
Chapter 2- Source Water Quality
implement mid-term and long-term improvements to BRWTF identified in
previous studies were noted, as described in the following sections.
1. pH
BRWTF finished water pH varied between 7.15 and 8.~78 s.u. during the
period of data reviewed, as shown on Figure 2-13.
2. TOC Removal
Historical TOC removal at BRWTF was reviewed as summarized in the
following.
• BRWTF has consistently met the TOC removal mandated by the
Stage 1 Disinfectants and Disinfection Byproducts Rule based on
the running annual average (RAA) of quarterly vaV'ues, as illustrated
on Figure 2-14.
• Since mid 2002 the RAA TOC removal at BRWTF has declined.
Several individual monthly values were below the required RAA.
3. Disinfection Byproduct Formation
Formation of currently regulated disinfection byproducts that result from
chlorination of drinking water was reviewed, as summarized below.
• Trihalomethane and haloacetic acid formation in areas served by
BRWTF followed a seasonally recurring pattern with highest
concentrations occurring in mid to late summer, as shown in
Figure 2-15 and 2-16, respectively.
• Both trihalomethane and haloacetic acid formation show increasing
trends in peak concentration since mid-2002, which correlates with
the trend of decreasing TOC removal previously noted.
4. Total Dissolved Solids and Sulfate
Review of total dissolved solids and sulfate data for BRWTF finished water
reveal the following:
~aaszz.zio 2-15 os~~aio~
10.0
9.5
9.0
~ NSDW Standard
8.5
._--- --- ---•---------- ------------------------------------•-------------•--...._---------
8.0 ---• -- ----- --- ----- --- ------- ------------------------------•----•----
Q 7.5 --- - - --- - - --- - • - - - -- -------- ---
7.0 COB pH Range Goal
6.5 ------------------------•-•----•---------•-•-----•---
----- •----------•------•--------------------------
NSDW Standard
6.0
5.5
5.0
07196 07l97 07/98 07199 07/00 07/01 07102 07/03 D7/04 07/05 07106
Date
~'-BRWTF Finnished Water ~,
BLACK & VEATCH City of Boulder, Colorado - Multi-Barrier Approach Study
Fi
. 6uilding ayy~~Idof difference~a
Boulder Reservoir Water Treatment Facility Finished Water pH gure
2-13
ENGRGv S~AT:~f? I~JFORh~ATiON GOVEflNM~N'f
2.5
~ 2.0
~
~
.
_
v'
a~
~
=
c~
~ 1.5
c~
4
0
~.
~ -
•-----
~
> 1.0 -------------------••- -... .-•-----••------------- ------• - ---•---•- ------ -- -----
O
~
~ NPDW Standard as Running Annual Average (RAA)
~
U
O
F-
0.5
0.0
07/96 07l97 U7/98 07/99 07/00 07/01 07/02 07/03 07/04 07/U5 07106
Date
~ Monthly Measurements Actual RAA -----• Alternative Compliance Criteria RAA
City of Boulder, Colorado - Multi-Barrier Approach Study
BLACK & VEATCH
6uilding a
orldof diiference ° Figure
W 2-14
Boulder Reservoir Water Treatment Facility TOC Removal
ENERGY WAffH INFORPAATION GOVEHNMENT
100
90
~ Stage 2 D/DBPR MCL
80 -- ----.....---•--- -----•-------•-------------------------••---- --------• -------------•-
~
70 -
;;~ ~~ `
~
~ '
~~~ 4
~ ~,~
.~ so .
1
J
~ ~
~
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50 ~
~ ~
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40 r
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- - - ------------• -~---
- ---- -- - r ------- - ------ - -
--- --- ':
. ,.~,^
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r - -
-~-
`l ' 1_
_ ,
-
COB TTHM Goal `~ ~`~
~
'~ ~~
30 ~~ ~a~~ ~ {~
~
Zo
10
0
07/98 07l99 07/00 07l01 07/02 07/03 07/04 07/05 07/06
Date
~-BRWTF Effluent -~-St. Mary's Church WWTP
City of Boulder, Colorado - Multi-Barrier Approach Study
BLACK & VEATCH Fi
gure
building a WOf~d of difference°°
2-15
Bo ulder Reservoir Water Treatment Facility Finished Water T THM
ENERGY -VATER INFOfiMAiION GOVERNMENT
100
90
80
70 ~ '
~ Stage 2 D/DBPR MCL ~
I
•
^ 60 ---- - ------------------•--
--•--------- •- -----=
--•--------••---•-•---------•--------~
J ~
~ ,
t '
~
..r 50
Q . ~
,'
~
'
/ ~.
2
40 ~
~ ,
30 --- --- ----------------- •--•- ---• -•~-----• ---•----•--•-•------------ •---~ ------
~I '~ .
~ COB HAAS Goal ~
20
10
0
07/98 07/99 07/00 07/01 07/02 07/03 07/04 07l05 07/06
Date
-f-BRWTF Effluent -~k-St. Mary's Church WWTP
City of Boulder, Colorado - Multi-Barrier Approach Study
BLACK & VEATCH Fi
gure
hwlding ayyp~Idof difference°
~
2-16
Boulder Reservoir Water Treatment Facility Finished Water HAA5
FNFHGY 4'1A1t.R IfdFDNF,9ltfIUN GOV[MNMENT
BRWTF 1NTEGRATED SOURCE WATER AND TREATMENT STUDY
Chapter 2- Source Water Qualrty
• TDS and sulfate levels in BRUVTF finished water vary throughout the
year, with peak concentrations in late winter to early spring, as
shown on Figure 2-17.
• Because there are no treatment processes for inorganic ion removal
currently installed at BRWTF, TDS and sulfate concentrations in
finished drinking water essentially mirror those of BFC and Boulder
Reservoir source waters.
E. Summary of BRWTF Source Water Quality
Based on review and extensive analysis of existing biological, physical,
and chemical water qualiry data, B&V believes that Carter Lake has superior
overall water quality as a raw water source for BRWTF compared with BFC and
Boulder Reservoir.
1. Microbial Source Water Quality Data
The microbial quality of water conveyed directly to the BRWTF through the
BFC is at risk, with potential for high levels of fecal matter as a result of acute
contamination episodes. Routine water quality monitoring of BFC has
demonstrated an increasing trend in fecal coliform contamination between 1997
and 2003. Giardia has routinely been detected in BFC water, and
Cryptosporidium has been detected occasionally. Protozoan contamination in
Boulder Reservoir has been detected at much lower concentrations compared to
BFC. Based on samples collected from BFC and Boulder Reservoir between
1997 and 2004, the BRWTF would fall into bin 1 under the LT2ESVIRR, requiring
no additional treatment for Cyptosporidium. Coliform bacteria and protozoan
pathogen levels in Carter Lake have routinely been at or below their respective
method detection limits.
Caution should always be exercised when interpreting protozoan
monitoring results, particularly in untreated surface waters, where turbidity and
suspended solids may interfere with (oo)cyst recovery. Effective detection of
protozoa in natural waters requires separation from aggregated colloids and
particles as well as other particles of similar size. The filtration technique used in
144922.210 2-~ 6 06/18/07
500 -- ----------------------------------------- ----------------------------------------------- ------------
NSDW TDS Standard
400
J
~
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~
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07/96 07/97 07l98 07/99 07/00 07/01 O7/02 07/03 07/04 OT/05 07l06
Date
f TDS -~ Sulfate
BLACK & VEATCH City of Boulder, Colorado - Multi-Barrier Approach Study
~
ENERGY buildingayyOrldotdifference°
WAtER INFORhtAT10N GUVEHN UENi
Boulder Reservoir Water Treatment Facility Finished Water TDS and Sulfate Figure
2"~ 7
BRWTF INTEGRATED SDURCE WATER AND TREAT1VlENT STUDY
Chapter 2- Source Water Quality
early Information Collection Rule monitoring was notoriously unreliable for
protozoan recovery and results based on this method are highly suspect. The
immunomagnetic separation technique used in EPA Method 1623 is somewhat
more reliable, but protozoan recovery from spiked natural water samples using
this technique is still routinely less than 50 percent. Finally, routine monitoring
samples only a very small fraction of 1 percent of total flow through BFC and
Boulder Reservoir, making the probability of capturing transient protozoan
contamination events unlikely.
2. Physical and Chemical Source Water Quality Data
Analysis of biological, physical, and chemical source water quality data
collected in Boulder Reservoir between 1997 and 2004 indicates mesotrophy,
(moderate nutrient levels) consistent with increased probability of algal blooms
and seasonal development of anoxic conditions at depth in the reservoir. Anoxia
in the reservoir hypolimnion can be correlated with microbially mediated release
of soluble manganese from bed sediment, which could in turn be entrained in
water supplied to the BRWTF through a submerged intake structure. In contrast,
Carter Lake is classified as oligotrophic (low nutrient levels) consistent with low
potential for algal blooms. Anoxic conditions in the hypolimnion of Carter Lake
have not been observed.
3. BRWTF Operational Water Quality Data
Review of operational data from BRVVI"F demonstrates trends of
decreasing TOC removal and increasing disinfection byproduct formation since
mid-2002. Because of the forthcoming shift from system-wide running annual
average to locational running annual average calculation of disinfection
byproduct concentrations for compliance purposes, the potential impacts of mid-
term and long-term improvements on TOC removal and DBP formation should be
carefully considered.
F. Sustainability of Carter Lake as a BRWTF Source
There will undoubtedly be seasonal and annual changes in Carter Lake
water quality in response to climactic conditions. However, 35 years of historical
data for Carter Lake do not indicate any long-term degradation in the overall
144922210 2-17 osiiaro7
BRWTF /NTEGRATED SOURCE WATER AND TRE~ATMENT STUDY
Chapter 2- Source Water Quality
water quality from this source. 8&V believes thaf the water quality of Carter Lake
will continue to be suitable as a water source for BRWTF for ~~ecades to come.
The following sections discuss our views on the future water quality of Carter
Lake.
1. Physical and Chemical Water Quality Trends
Important water quality parameters including pH, alkalinity, and
hypolimnetic oxygen concentration have not shown any deteriorating trends with
time, as shown in Figures 2-18 and 2-19. The minimum recorded hypolimnion
oxygen concentration in Carter Lake is approximately 3 mg/L, indicating that fully
anoxic conditions associated with taste and odor and soluble iron or manganese
issues do not occur in Carter Lake. Total dissolved solids (TDS) and dissolved
sulfate have shown a slight decreasing trend based on historical data
(Figure 2-1), indicating improving water quality.
2. Trophic Status
Perhaps the best indicator of the overall water qualit~i of a lake is its
trophic status, which reflects the biological productivity in the water body.
Biological productivity in a water body is frequently classified based on potential
for algal growth, which if excessive may lead to rapid seasonal changes in water
quality. Lakes and reservoirs are classified as oligotrophic, mesotrophic,
eutrophic, or hypereutrophic based increasing potential for excessive algal
growth or seasonal algal "blooms". A number of trophic status indices (TSI) have
been proposed based on a single or multiple water quality parameters as
measures of algal biomass, including Secchi depth (water clarity), total
phosphorus level, and chlorophyll a.
Historical trends for Secchi depth, total phosphorus, and chlorophyll a in
Carter Lake have not shown any tendency toward lower water quality, as shown
in Figures 2-20 through 2-22. Of these parameters, chlorophyll a is the most
direct indication of algal biomass. Carter Lake would be classified as oligotrophic
based on chlorophyll a content, with a low potential for water quality degradation
due to algal blooms (Figure 2-22).
iaaszz.zio 2-18 osi~aro~
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Date
~- pH ~ Alkalinity
City of Boulder, Colorado - Multi-Barrier Approach Study
BLACK & VEATCH ure
Fi
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' building a WOC~d pf d€fference °
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pH and Alkalinity in Carter Lake
ENERGv WATER INFORMATION GOVERNMENT
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Date
-l-Hypolimnion DO
BLACK & VEATCH City of Boulder, Colorado - Multi-Barrier Approach Study
~tl building aylypr~~of difference~ FIgU~B
ENERGV WATER INFORMATiOtv GOVEHMMeNl' Hypolimnetic Dissolved Oxygen in Carter Lake 2-19
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Date
~ Secchi Depth
BLACK & VEATCH City of Boulder, Colorado - Multi-Barrier Approach Study
~ building ayyO~Idof difference~° Figure
p Secchi Depth in Carter Lake 2'20
ENERGV ~VATER INFOFiMAT10M GOVERNMENT
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Date
•Total Phosphorus
BLACK & VEATCH City of Boulder, Colorado - Multi-Barrier Approach Study
Fi
, building aWOr~dof difference •
ENEHGY ~~VATEA INFORMATI~N GOVERNM11EN1~
Total Phosphorus in Carter Lake gure
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Date
-~Chlorophyl a
City of Boulder, Colorado - Multi-Barrier Approach Study
BLAGK & VEATCH Figure
bu+lding ayyp{~~dof differe~ce~°
Chlorophyll a in Carter Lake 2"22
ENERGY WRTEfl INFORMATION GOVERNMENT
BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Chapter 2- Source Wafer Quality
3. Watershed Protection
Carter Lake has a well protected watershed with minimal potential for
future water quality degradation due to point or non-point contaminant sources.
Two dams form Carter Lake in a natural depression in topography, resulting in a
very small watershed, as shown in Figure 2-23. The lake is surrounded by steep
forested terrain and has no natural tributaries. Much of the surrounding land
resides in protected forests, parks, and recreational areas. Lands bordering
Carter Lake are also not suitable for large scale agricultural concerns, and
natural topography is not amenable to large scale industrial operations. Carter
Lake has a capacity of 112,230 ac-ft providing a large dilution volume for any
contaminant introduced directly or from surface runoff. Long-term water quality
degradation due to concentration of point or non-point contaminant inputs is
mitigated by seasonal water use, with greater than 50 percent annual turnover in
the lake being typical.
The Colorado-Big Thompson (CBT) Project supplies water to Carter Lake
through a series of reservoirs, lakes, tunnels, and conduits. As such, the water
quality in Carter Lake is to a large extent dependent on water quality in upstream
waterbodies including Flatiron Reservoir (760 ac-ft), Pinewood Reservoir
(2,181 ac-ft), Lake Estes (3,068 ac-ft), Mary's Lake (5-27 ac-ft), Grand
Lake/Shadow Mountain Reservoir (17,354 ac-ft), and ultimately Lake Granby
(539,800 ac-ft), as shown on Figure 2-24. Flatiron and Pinewood Reservoirs
have similar topographic features as Carter Lake and are located in undeveloped
areas. Lake Estes has natural inflow from the Big Thompson River water shed in
R~cky Mountain National Park and CBT flow from Mary's Lake. Mary's Lake has
no measurable natural inflow and receives CBT water from Grand Lake via the
Alva B. Adams Tunnel. Grand Lake is surrounded by Rocky Mountain National
Park on three sides and Shadow Mountain Reservoir on the fourth. CBT water
collected on the West Slope is pumped to Grand Lake through Shadow Mountain
Reservoir.
Because of the native topography and protected status of much of the
land surrounding the CBT Lakes and Reservoirs that ultimately supply Carter
Lake, B&V believes that municipal, agricultural, or industrial development on the
scale necessary to substantially degrade water quality in the CBT watershed is
not likely during the 30-year planning horizon of our study. Although
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City of Boulder, Colorado - Multi-Barrier Approach Study
Figure
2-23
Carter Lake Watershed Topography
ENEfiGY NIATER INFORMATION GOVERf~''~tENl~
BLACK & VEATCH City of Boulder, Colorado - Multi-Barrier Approach Study
~ building ayypr~~af ditFerence~° Figure
Colorado-Big Thompson Project Supply to Carter Lake 2'24
ENEHGv 1VAiL.H ItJFOfi~AAiIUN GOVERNMENT
BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Chapter 2- Source Water Quality
development will undoubtedly continue in selected locations adjacent to CBT
facilities, most notably Estes Park and Grand Lake, natural topography will tend
to limit this growth and any potential adverse impact it might have on CBT water
quality.
4. CBT System Operation
The operational practices used by The Northem Colorado Water
Conservancy District to manage the water supply in the CBT system also tend to
mitigate any impacts of seasonal water quality fluctuations in upstream reservoirs
and Lakes on water quality degradation in Carter Lake. The vast majority of CBT
water transferred to Carter Lake in any water year occurs during the winter and
early spring, when water quality is not affected by temperature stratification, algal
blooms, or hypolimnetic oxygen depletion in the upstream lakes and reservoirs.
Furthermore, the large storage volumes and detention times of the CBT supply
system to Carter Lake provide the opportunity for substantial natural attenuation
of micropollutants that could potentially enter from intentional or unintentional
sources.
5. Potentiai for Contamination by Pathogens
The potential for future contamination of CBT water by pathogenic
protozoa such as Giardia and Cryptosporidium is an important consideration
regarding the need for additional treatment at BRWTF. B&V believes that there
is a low probability that pathogenic protozoa concentrations in CBT water
delivered to Carter Lake will increase substantially during the 30-year planning
horizon of our study. Protozoa such as Giardia and Cryptosporidium do not
reproduce outside of an animal host, and therefore do not independently multiply
in natural waters. Contamination of natural waters by Giardia and
Cryptosporidium occurs through input of human fecal matter in inadequately
treated municipal and domestic wastewater, or animal fecal matter from wildlife
or domestic livestock. There are currently four municipal wastewater treatment
facilities permitted by USEPA located in the CBT watershed area, which serve a
combined population of approximately 20,000 people. B&V is unaware of any
water quality monitoring data that would suggest that these facilities are currently
releasing discharges to the CBT system that result in Cryptosporidium
~aaszz.z~o 2-20 osnaio~
BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Chapter 2- Source Water Quality
concentrations above natural background levels (LT2ESWTR bin 1). Based on
topography and protected surrounding land uses B&V believes that it is unlikely
that a concentrated animal feeding operation of sufficient magnitude to negatively
impact CBT water quality will be located in the CBT watershed. Based on the
size of the CBT system we also believe that there is a negligible possibility of
substantial and widespread Gryptosporidium contamination of CBT water from
wildlife fecal matter.
144922 210 2'2 ~ O6/18/07
BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Chapter 3 - Contaminant Barriers
Chapter 3
Delivery Alternative Contaminant Barriers
This chapter describes the different categories of contaminant barriers,
defined by regulatory requirements and City finished water quality goals, for
drinking water produced at BRWTF with each of the source waters considered in
this study. The two water sources for BRWTF considered here were
(1) seasonal use of the BFC and Boulder Reservoir and (2) direct conveyance to
BRWTF through a dedicated pipeline. These two sources provide distinctly
different raw water quality to BRWTF as discussed in Chapter 2, which impacts
the combination of drinking water treatment processes that best addresses
contaminant barriers in a cost-effective multi-barrier water delivery approach.
The BRWTF currently meets or exceeds all National Primary and
Secondary drinking water regulations during routine operation, and based on
source water quality data reviewed in Chapter 2, will likely continue to do so for
the foreseeable future. However, finished water quality in areas served by
BRWTF is vulnerable to short-term degradation due to seasonal variation in
Boulder Reservoir water quality and acute contamination episodes in either BFC
or Boulder Reservoir. Of particular concern are microbial contamination in BFC
or Boulder Reservoir, DBP formation during treatment and distribution,
contamination by organic micro-pollutants in BFC and Boulder Reservoir,
seasonal manganese uptake, taste or odor episodes in Boulder Reservoir, and
non-uniform total dissolved solids (TDS) and sulfate concentration across the
distribution system when BRWTF uses Boulder Reservoir as its source.
Because these factors pose a potential threat to drinking water quality, the
City has established drinking water quality goals that are in some instances more
stringent than state or federal regulatory requirements to ensure public health.
Appendix 1 lists the City's water quality goals. For the purposes of this study, the
minimum contaminant barrier requirements were those specified by enforceable
USEPA and CDPHE Primary Drinking Water Standards. Contaminant barriers
associated with Secondary Drinking Water Standards and City drinking water
quality goals were also evaluated in this report. However, the contaminant
iaasnz~o 3-1 osnaio~
BRWTF INTE6RATED SOURCE WATER AND TREATMENT STUDY
Chapier 3 - Confaminant Barriers
barriers considered were not required to completely satisfy these non-
enforceable secondary standards in all cases, largely for compelling economic
reasons.
A. Barriers for Microbial Pathogen Contro!
Over the past two decades the Environmental Protection Agency (EPA)
has issued a series of increasingly stringent Drinking Water Regulations
designed to protect the public from microbial pathogens such as viruses, Giardia,
and Cryptosporidium that may be present in surface water supplies. Because
turbidity is often used as an indicator of microbial water quality, it is also
regulated in drinking water produced from surface water sources. Relevant
regufations include the Surtace Water Treatment Rule (SWTR), Interim
Enhanced Surface Water Treatment Rule (IESWTR), LT1ESWTR, and most
recently the Long-Term 2 Enhanced Surface Water Treatment Rule
(LT2ESWTR). Each rule specifies treatment techniques required to achieve
specified levels of physical removal or inactivation of specific microbial
pathogens in drinking water.
1. Overview
Turbidity in water is caused by suspended particles that scatter or absorb
incident light, thereby reducing the water's clarity. Soii and mineral weathering
products and microorganisms including bacteria, algae, and protozoa are the
principal sources of turbidity in natural waters, either occurring naturally or as the
result of agricultural, municipal or industrial activity. The IESWTR established a
combined filter effluent (CFE) limit for turbidity of less than or equal to
0.3 nephelometric turbidity units (NTU) in at least 95 percent of monthly samples
and a limit of 1 NTU for all samples, with additional limits on individual filter
effluent (IFE) turbidity. The City has set internal water quality goals for turbidity
of less than or equal to 0.1 NTU in at least 95 percent of ail IFE samples and less
than 0.15 NTU for all CFE samples.
Turbidity removal is perhaps the oldest form of drinking water treatment,
traditionally relying on ctarification and granular media filtration. Standard
practice now includes chemical pre-treatment that modifies particle surface
chemistry to improve removal. Enhanced clarification processes such as
iaaszz.zio 3-2 osnaio~
BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Chapter 3 - Contaminant Barriers
ballasted flocculation and dissolved air flotation (DAF), as well as membrane
filtration are also now being used to for turbidity removal.
Based on an improved understanding of Cryptosporidium occurrence in
surtace waters and treatment process limitations, LT2ESWTR has established
risk-targeted log-removal/inactivation levels for Cryptosporidium in addition to
those specified in earlier rules. The primary purposes of this rule are to protect
public health from illness due to Cryptosporidium and other microbial pathogens
in drinking water and to address risk-risk trade-offs with the control of disinfection
byproducts. Because this regulation links the required level of drinking water
treatment with source water quality, a careful evaluation of source water
protection and treatment options is required to ensure public health protection
and regulatory compliance.
LT2ESWTR classifies source water quality into four bins based on
average Cryptosporidium concentration and treatment type, and specifies
associated levels of additional treatment required. Table 3-1 lists the required
levels of additional treatment for WTPs that utilize conventional treatment
consisting of chemical coagulation, flocculation, clarification, and granular media
filtration.
Table 3•1
LT2ESWTR Cryptosporidium Treatrnent
Requirements for Conventional WTPs
Additional
Bin Removal/Inactivation
Designation Cryptosporidium Concentration Treatment Required
(oocy5ts/L)
1 Lessthan 0.075 None
2 0.075 or higher, but less than 1.0 1-log
3 1.0 or higher, but less than 3.0 2-log
4 3.0 or higher 2.5-log
~aaszz.z~o 3-3 osneioi
BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Chapter 3 - Contaminant Barriers
As a public water system serving a population greater than 100,000, the
City is required to conduct 24 months of initial source water monitoring beginning
in October 2006, or submit grandfathered existing monitoring data to establish
average Cryptosporidium concentrations for LT2ESWTR bin determination at
BRWTF. Historical Cryptosporidium monitoring data for Carter Lake, BFC, and
Boulder Reservoir collected between 1997 and 2006 indicate that these source
waters would be classified in Bin 1 with respect to LT2ESWTR compfiance,
requiring no additional treatment for Cryptosporidium. However, if grandfathered
existing data were not accepted by the regulatory primacy agency, then
LT2ESWTR bin classification would be based on the results of additional source
water monitoring. If these additional monitoring data were to indicate
substantially higher Cryptosporidium levels in either BFC or Boulder Reservoir
than historical levels, additional Cryptosporidium treatment requirements at
BRWTF could be triggered.
As part of its water quality goal setting process, the City has determined
that a minimum of one additional log-removal/inactivation of microbial pathogens
above regulatory requirements is prudent to protect public health. Table 3-2 tists
the required and target log-removal/inactivation for regulated microbial
pathogens based on meeting federal regulations and City water quality goals.
Table 3-2
Required and Target Log-Removal/Inactivation
for Regulated Microbial Pathogens
Re
ulation/Goal Pathogen
g
Viruses Giardia Cryptosporidium
Regulatory Requirement 4 3 3
City Goal 5 4 5
Assumes LT2ESWTR Bin 1 classification.
~z~Provides for potential BFC and Boulder Reservoir LT2ESWiR bin 2 classification.
744922210 3-~{ O6/18/07
BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Chapter 3 - Contaminant Barriers
2. Existing Barriers for Microbial Pathogen Control
BRWTF utilizes chemical pre-treatment, DAF, and granular media filtration
for turbidity control. Historical operating data indicates turbidity in finished water
from BRWTF has exceeded the City's goal 0.1 NTU 14 percent of the time.
Existing barriers for microbial pathogen control in place at BRWTF include
conventional treatment (coagulation, flocculation, dissolved air floatation, and
filtration) and chemical disinfection with free-chlorine. The presumptive log-
removal/inactivation of viruses, Giardia, and Cryptosporidium credited to
conventional treatment under the SWTR and IESWTR are listed in Table 3-3.
The balance of virus and Giardia treatment required under the SWTR is currently
provided by chemical disinfection with free-chlorine.
Table 3-3
Regulatory Requirements and Additional Pathogen
Removal/Inactivation to Meet City Goals at BRWTF
Conventional Regulatory Additional Needed
Pathogen
Treatment Disinfection
Requirement
to Meet City Goal
Viruses 2 2 4 ~
Giardia 2.5 0.5 3 1
Cryptosporidium 3 -- 3' 2*
Assumes LT2ESWTR Bin 1 classification.
3. Potential Additional Barriers for Microbial Pathogen Control
The LT2ESWTR Microbial Toolbox is a list of potential treatment options
for additional Cryptosporidium removal/inactivation, as given in Table 3-4.
Table 3-4 also gives a preliminary evaluation of the potential applicability of these
techniques at BRWTF. Because of the pristine microbial quality of Carter Lake is
low (Chapter 2, Section C.1.a), full containment of source water in a dedicated
pipeline to BRWTF would also provide an additional barrier.
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BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Chapter 3 - Contaminant Barriers
Table 3-4
LT2ESWTR Microbial Toolbox
Treatment Removal/
APPlicability Comments
Technique Inactivation Credit
Source Water Protection and Management
Watershed Control Program 0.5 Likely Treatment cost avoidance
and direct credit
Prefiltration
Presedimentation and Coagulation 0.5 Possible Reduces acute loading to
BRWTF
Two-Stage Lime Softening 0.5 Unlikely Not ~equired by source
water hardness
Bank Fiftration 0.5 -1.0 Possible Boulder Reservoir defivery
alternative
Treatment Performance
Combined Flter Performance 0.5 Likely Presumptive operational
credit
Individual Filter Performance 0 5 Likely Presumptive operational
credit
Demonstration of Performance Variable Unlikely Requires state approved
protocol
Additional Filtration
Bag and Cartridge Filters 2.0 singly, Possible Additional pumping, small
2.5 in series footprint
Membrane Filtration Demonstrated removal Possible Retrofit in existing filter
effaency boxes
Second Stage Filtration 0.5 Unlikely Additional pumping likely
Slow Sand Filtrahon 2.5 - 3 0 Unlikely Additional pumping likely
Inactivation
Chlorine Dioxide Based on Likely Manganese and taste &
measured CT odor control
Ozone Based on Likely Manganese and taste &
measured CT odor control
UV Based on validated UV Likely Advanced oxidation of EDCs
dose with HZOZ
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BRWTF INTE('aRATED SOURCE WATER AND TREATMENT STUDY
Chapter 3 - Contaminant Barriers
B. Barriers for Disinfection Byproduct Control
DBPs are compounds formed during drinking water treatment through
reaction of chemical disinfectants with either organic or inorganic constituents
present in the source water.
7. Overview
The most widespread and well documented class of DBPs is halogenated
organic compounds formed by reaction of free-chlorine and natural organic
matter. Typically, only 30 to 60 percent of halogenated organic DBPs are
chemically identifiable, with trihalomethanes (THMs) and haloacetic acids (HAAs)
occurring in the highest concentrations. The Stage 2 Disinfectants and
Disinfection Byproduct Rule (Stage 2 DBPR) standards for total THMs and five
HAAs (HAAS) are 80 and 60 micrograms per liter (µg/L), respectively, measured
as locational running annual averages (LRAAs) at each monitoring site. The City
has set internal water quality goals of 40 µg/L and 30 µg/L for THMs and HAAs
as LRAAs, respectively.
Disinfection of drinking water with ozone leads to formation of low-
molecular weight organic byproducts through oxidation of NOM, and bromate
(Br03 ) by oxidation of bromide (Br ). The organic by-products are primarily
aldehydes, ketoacids, and carbo~rylic acids that are not currently believed to pose
a health hazard and are therefore not regulated in drinking water. Bromate is
believed to be a human carcinogen and is currently regulated by the Stage 1
Disinfectants and Disinfection Byproduct Rule (Stage 1 DBPR) at 10 µg/L, with a
future maximum contaminant level (MCL) of 5 µg/L under consideration. The
City currently has no internal water quality goal for bromate.
Chlorine dioxide (CIOZ) is much less reactive with NOM compared with
free-chlorine or ozone, and produces very few halogenated organic DBPs.
However, the reduced inorganic byproducts chlorite (CIO2~ and chlorate (CI03~
may be produced during onsite CIOz generation or by CIOz oxidation of NOM and
reduced iron or manganese. Stage 1 DBPR set an MCL of 1 mg/L for chlorite.
Chlorate is currently not regulated in drinking water due to a lack of conclusive
evidence regarding adverse health effects. The City currently has no internal
water quality goals for chlorite or chlorate.
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BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Chapter 3 - Contaminant Barriers
Combined-chlorine (NHZCI - monochloramine) is also much less reactive
with NOM than free-chlorine, producing on average less than 20 and 50 percent
of the THM and HAA concentrations, respectively, at comparable disinfectant
concentrations. Reaction between combined-chlorine and certain cationic resins
and polymers has recently been implicated in the formation of
nitrosodimethylamine (NDMA), which is classified as a probable human
carcinogen by USEPA. NDMA is not currently regulated in drinking water, but
has an estimated 10~ cancer risk at 0.7 nanograms per liter (ng/L), which is
below the level often measured in chloraminated drinking water. The City
currently has no internal water quafity goal for NDMA.
2. Existing Barriers for DBP Control
DBP precursor removal at BRWTF relies solely on TOC removal by
enhanced coagulation; alternative oxidants are not currently used, nor is
activated carbon adsorption applied. Although BRWTF has consistently met the
treatment technique requirement for TOC removal (Figure 2-14), the City's THM
and HAA water quality goals have not been met consistently (Figures 2-15 and
2-16). Between 1998 and 2006, the City's goals have been exceeded in 56 to
70 percent of THM samples, and 65 to 90 percent of HAA samples, collected
from locations served exclusively by the BRWTF.
3. Potential Additional Barriers for DBP Control
Treatment technologies that seek to minimize DBP formation follow one of
three strategies related to the reactions between chemical disinfectants and
organic or inorganic source water constituents: (1) remove the undesirable
byproduct once formed, (2) alter the reaction conditions so as to reduce
byproduct formation, or (3) reduce or remove one of the byproduct precursors.
Because DBPs are generally non-volatile, solid phase adsorption processes
have long been viewed as candidates for DBP removal from finished drinking
water. Granular activated carbon (GAC) adsorption and ion exchange (IX) have
been e~ensively explored as treatment techniques for organic and inorganic
DBP removal, respectively. However, these processes have not been widely
deployed for DBP removal from finished drinking water because of limitations
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BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Chapter 3 - Contaminant Barriers
including insufficient adsorption capacity, lack of specificity for targeted DBPs,
undesirable interactions with residual disinfectants, and operational and
economic considerations.
Controlling DBP formation by altering reaction conditions such as
temperature or contact time is of only limited value or practicality. Utilities have
very little if any control over source and finished water temperatures, and
lowering water temperature during treatment is economically unviable. Although
the point(s) of disinfectant application may sometimes be moved further
downstream in the treatment process train, disinfection contact time
requirements and distribution system residence time limit the extent to which
contact time can be reduced. For these reasons, minimizing DBP formation
during drinking water treatment has largely focused on reducing or removing
DBP precursors, and has governed development of the interrelated set of
microbial and DBP regulations over the past decade.
Strategies for DBP precursor removal include use of alternative
disinfectants, precipitative NOM removal by enhanced coagulation, and NOM
adsorption on activated carbon. Ozone, chlorine dioxide, chloramines and UV
light have been used to either partially or completely replace free-chlorine,
thereby lowering THM and HAA formation. However, alternative chemical
disinfectants do produce other DBPs as previously discussed. Stage 1 DBPR
mandates a treatment technique for NOM removal in facilities that utilize
conventional treatment of surface water based on source water total organic
carbon (TOC) and alkalinity concentrations, as indicated in Table 3-5.
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BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Chapfer 3 - Contaminant Barriers
Table 3-5
Percent TOC Removal Required by Enhanced Coagulation for
Surtace Water Systems Utilizing Conventional Treatment
Source Water TOC Source Water Alkalinity (mg/L as CaC03)
(mg/L) 0-60 >60 -120 > 120
> 2.0 to 4.0 35.0 25.0 15.0
> 4.0 to 8.0 45.~ 35.0 25.0
> 8.0 50.0 40.0 30.0
Alternative Compliance Criteria:
(1) Source water TOC < 2.0 mg/L
(2) Finished water TOC < 2.0 mg/L
(3) Source water TOC < 4.0 mg/L, alkalinity > 60 mg/L as CaC03, TTHM < 40 µg/L, and
HAA < 30µg/L
(4) TTHM < 40 µglL and HAA < 30µg/L, and on{y chlorine used for disinfection and residual
maintenance
(5) Source water SUVA prior to any treatment <_ 2.0 Umg m
(6) Treated water SUVA <2.0 Umg m
C. Barriers for Organic Micro-Pollutant Control .
Organic micro-pollutants enter source waters from industrial and municipal
effluents, agricultural runoff, and unregulated waste discharge.
1. Overview
Organic micro-pollutants encompass a wide range of chemical
compounds with diverse physical and chemical properties. Historically important
classes of synthetic organic compounds (SOCs) include solvents, plasticizers,
propellants, petroleum additives, chemical intermediates, herbicides, and
pesticides. Emerging SOC classes of concern that are not currently regulated
include endocrinologically active compounds (EDCs), pharmaceutically active
compounds (PhACs), and personal care products (PCPs). Although SOCs
typically occur at low concentrations in source waters, and at trace levels in
drinking water supplies, many of these compounds are highly toxic or
carcinogenic and therefore pose a health risk if present in drinking water. There
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BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Chapter 3 - Confaminant Barriers
are currently national primary drinking water standards for 62 SOCs and pending
standards for another 38 listed in the Contaminant Candidate List 2. The City
currently has no internal water quality goal for specific organic micro-pollutants.
2. Existing Barriers for Organic Micropollutant Control
There are currently no known industrial or municipal effluent discharges to
Carter Lake, BFC, or Boulder Reservoir; although, all three water sources for
BRWTF are potentially subject to organic micro-pollutant contamination to
varying degrees through surface runoff and unregulated waste releases. Carter
Lake is the least susceptible of BRWTF sources because of its remote location,
small catchment area and lack of natural tributaries, and restricted adjacent land
usage. Boulder Reservoir is somewhat more vulnerable to organic micro-
pollutant contamination due to natural tributaries and ditches that flow in and
extensive recreational use. BFC is highly vulnerable to organic micro-pollutant
contamination because of its extended length with virtually uncontrolfed access,
numerous outfalls and street crossings, and adjacent residential, commercial,
agricultural, and recreational land uses. There are no dedicated SOC treatment
processes at BRWTF, and only very limited organic pollutant removal is provided
by DAF and co-precipitation during natural organic matter (NOM) coagulation.
3. Potential Additional Barriers for Organic Micropollutant Control
Organic micro-pollutant control in drinking water supplies utilizes
watershed management to limit effluent discharges, as well as treatment
processes including air stripping, chemical oxidation, coagulation, activated
carbon adsorption, reverse osmosis, and advanced oxidation for removal during
treatment. Chemical characteristics such as volatility, polarity, charge, molecular
weight, and solubility, determine which processes are appropriate for SOC
removal during drinking water treatment. Because the potential for introduction
of organic micropollutants into Carter Lake is low (Chapter 2, Section C.1), full
containment of source water in a dedicated pipeline to BRWfF would also
provide an additional barrier.
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.. BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
~ Chapter 3 - Confaminant Barriers
D. Barriers for Manganese Control
Manganese may be present in ground and surface waters that are in
contact with manganese containing minerals, occurring as either soluble Mn2+
(reduced form) or precipitated MnOZ (oxidized form), depending on pH and
oxygen concentration.
1. Overview
Aesthetic issues associated with manganese in drinking water include
staining of laundry and fixtures and unpleasant taste. Manganese concentrations
of less than 0.5 milligrams per liter (mg/L) may promote bacterial growth in
reservoirs and drinking water distribution systems. Consumer complaints
regarding aesthetic issues associated with manganese in drinking water have
been documented at concentrations as low as 0.02 mg/L. There are presently no
known adverse health effects of manganese in drinking water, but the USEPA
has set a secondary maximum contaminant level (SMCL) for manganese at
0.05 mglL based on aesthetic concerns. The City has set an internal goa{ of
0.03 mg/L for manganese in finished drinking water.
2. Existing Barriers for Manganese Control
Manganese concentrations in Carter Lake have historically been very low
year-round. Manganese concentrations increase only slightly as a result of
conveying water to BRWTF through BFC. However, seasonal manganese
mobilization is routinely observed in Boulder Reservoir during late summer and
early fall due to hypolimnetic anoxia produced by thermal stratification. Although
the manganese concentration in the hypolimnion of Boulder Reservoir exceeds
the City's goal in 33 percent of samples, with levels of 0.5 mg/L to 1.0 mg/L not
uncommon, manganese loading in BRWTF influent has historically been
minimized by using the low manganese BFC source almost exclusively during
periods when stratification results in mobilization. Because oxidation of Mn2+ with
oxygen and free-chlorine is relatively slow at pH less than 9.5, the efficiency of
manganese removal for the conventional treatment process configuration
currently in place at BRWTF inay not be sufficient if Boulder Reservoir was used
as the water source year-round.
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BRWTF INTE('aRATED SOURCE WATER AND TREATMENT STUDY
Chapter 3 - Contaminant Barriers
3. Potential Additional Barriers for Manganese Control
Manganese control during drinking water treatment most often involves
oxidation of soluble Mn2+ to particulate Mn02, with subsequent removal by
clarification or filtration. Manganese removal through autocatalytic adsorption
and oxidation on MnOZ coated filter media surtaces is also practiced, and less
frequently by ion exchange, nanofiltration/reverse osmosis or precipitative
softening. Because the potential for soluble manganese release from bed
sediments in Carter Lake is low (Chapter 2, Sections C.1.b and C.1.c), full
containment of source water in a dedicated pipeline to BRWTF would also
provide an additional barrier.
E. Barriers for Taste and Odor Control
Objectionable tastes and odors in drinking water may occur due to the
presence of microbial metabolites and degradation products, anthropogenic
valatile and synthetic organic compounds, and naturally occurring inorganic
compounds.
1. Overview
Numerous microbial species belonging to cyanobacteria, green algae,
diatom, and flagellate groups that may be present in surFace waters produce
odors variously described as sweet, grassy, musty, earthy, swampy, fishy, and
septic. Geosmin and 2-methylisoborneol (MIB) are the most well known
microbial odor-causing metabolites found in drinking water supplies, producing
earthy and musty odors, respectively. Medicinal and phenolic off-tastes and
odors are often associated with drinking water supplies developed from source
waters that receive organic solvents, pesticides, and petroleum products from
industrial effluent, agricultural runoff, and liquid waste disposal. Often, these
chemicals produce tastes and odors that are not directly attributable to a parent
organic compound, but rather to chlorinated disinfection byproducts that occur in
discharged waste effluents or finished drinking water. Thermal stratification in
lakes and reservoirs often leads to anaerobic conditions at depth, releasing
inorganic taste and odor compounds through mobilization of soluble iron and
manganese (Fez+ and Mn2') from insoluble oxide minerals in bottom sediments,
as well as sulfide production. There are currently no national drinking water
iaaszz.zio 3-13 osnaio~
~ BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
L Chapter 3- Contaminant Barriers
regulations for taste; however, USEPA has set a SMCL for odor at a threshold
odor number of three. The City has set an internal water quality goal of no
detectable tastes or odors in finished drinking water.
2. Existing Barriers for Taste and Odor Control
BRWfF currently depends largely on source water control strategies for
taste and odor control, as chemical oxidation with free-chlorine is only marginally
effective at controlling algal metabolites and oxidizing soluble manganese.
Algicides are periodically applied in BFC, but not to Carter Lake or Boulder
Reservoir. There is no aeration for volatile organic removal or activated carbon
or ion exchange processes for soluble contaminant removal, nor is there is a
routine monitoring program for seasonal formation of algal taste and odor
compounds in Carter Lake, BFC, or Boulder Reservoir.
3. Potential Additional Barriers for Taste and Odor Control
Taste and odor control in drinking water supplies may rely on source water
management or removal during treatment, or frequently a combination of both
strategies. Source water management strategies include lake and reservoir
aeration, chemical inhibition of algal growth, watershed management to limit
nutrient input, and effiuent discharge restrictions. Chemical characteristics of
taste and odor compounds such as volatility, polarity, charge, molecular weight,
and solubility, determine which processes are appropriate for their removal
during drinking water treatment. Treatment processes commonly used for taste
and odor control include aeration, chemical oxidation, activated carbon
adsorption, ion exchange, and precipitation. Because the potential for
objectionable taste or odor episodes in Carter Lake is low (Chapter 2,
Section C.1.c), full containment of source water in a dedicated pipeline to
BRWTF would also provide an additional barrier.
F. Barriers for Inorganic Contaminant Control
Natural waters contain a variety of inorganic constituents that occur
primarily as the result of mineral weathering and leaching reactions in soil,
sediment, and rock formations; although, industrial, municipal, agricultural, and
surface runoff effluents may in some instances contribute inorganic constituents.
~aas2zz~o 3-14 osneio~
BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Chapter 3 - Contaminant Barriers
1. Overview
Inorganic constituents typically occur in ionic form in aqueous solution,
and may be present as suspended and colloidal solids or dissolved species.
Major cations (positively charged) in natural waters include sodium, potassium,
calcium, magnesium, iron, and manganese; whereas, major anions (negatively
charged) include bicarbonate, chloride, sulfate, sulfide, nitrate, nitrite, fluoride,
and silicate. Other trace inorganic constituents that may be present in source
waters are alkali and alkaline metals, other metallic elements, and nonmetals.
There are currently National Primary Drinking Water Standards for 16 inorganic
elements and compounds, and National Secondary Drinking Water Standards for
10 inorganics. There is also a National Secondary Drinking Water Standard for
pH of 6.5 to 8.5 standard units (s.u.), as an indicator of finished water quality and
corrosivity. The City has set internal water quality goals for sodium (5 to
20 mg/L), sulfate (less than 20 mg/L), TDS (less than 100 mg/L), fluoride
(0.9 ± 0.1 mg/L), and pH (7.8 ± 0.2 s.u.) that are more restrictive than required by
state and federal regulations.
2. Existing Barriers for Inorganic Contaminant Control
BRWTF utilizes conventional treatment for suspended and colloidal
inorganic contaminant removal. No dedicated processes for dissolved inorganic
contaminant removal are currently in place at BRWTF. The City's water quality
goals for sulfate and TDS have historically been routinely exceeded
(Figure 2-17). In addition, finished water pH at the BRWTF has routinely been
outside the City's desired range, exceeding the upper limit and falling below the
lower limit 10 percent and 42 percent of the time, respectively.
3. Potential Additional Barriers for Inorganic Contaminant Control
Suspended and colloidal inorganic constituents may be effectively
removed from source waters by standard treatment methods including
coagulation, clarification, and filtration. However, with the exception of several
regulated metals, dissolved inorganic constituents are typically only poorly
removed by these methods, if at all. The concentrations of multivalent ions may
be reduced by precipitative softening or ion exchange, but reverse osmosis is the
only practical treatment method to lower TDS or remove monovalent ions.
~aaszz.z+o 3-15 osnaioi
BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Chapter 3 - Coniaminant Barriers
Because the potential for naturally-occurring or human-induced inorganic
contamination in Carter Lake is very low (Chapter 2, Section C.1.c), fuli
containment of source water in a dedicated pipeline to BRWTF would also
provide an additional barrier.
iaaszz.zio 3-16 osnaio~
BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Chapter 4 - Decision Criteria
Chapter 4
Multi-Barrier Approach Decision Criteria
This chapter describes the criteria developed as part of a structured K-T~
decision analysis model used to rank BRWTF multi-barrier water delivery
alternatives. This set of decision criteria forms the basis of a fair and balanced
evaluation of BRWfF multi-barrier water delivery alternatives. City staff
developed decision model criteria in 5 categories including finished water quality,
source water, treatment operations, risk, and environmental and public
acceptance.
A set of preliminary decision model pertormance criteria was presented to
City staff by B&V in a workshop held on August 16, 2006. Over the next several
months, an ad hoc City staff committee (BRWTF Multi-Barrier Project Working
Group) representing drinking water quality, water resources, operations, and
senior management functions refined the preliminary decision model
pertormance criteria through a series of scheduled meetings and informal
communications. Based on the collective expertise and experience of the Project
Working Group members, the set of decision model pertormance criteria
ultimately chosen was reviewed and finalized in a workshop held on
December 14, 2006.
A. Mandatory MUST Criteria
As described in Chapter 1, performance criteria in K-T~ decision analysis
are classified either as MUST criteria that each candidate problem solution must
absolutely satisfy in order to be included in the decision process, or WANT
criteria that are desirable but not mandatory for each candidate problem solution
to satisfy. Two MUST decision criteria were developed by the Project Working
Group.
1. Regulatory Compliance
For a candidate decision model alternative to be considered as an
acceptable BRWTF multi-barrier water delivery approach it must be capable of
continuously meeting all enforceable USEPA and CDPHE drinking water
~aaszzz~o 4-1 osnaio~
BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Chapter 4 - Decision Criteria
regulations and standards. This MUST criterion assumes that BRWTF will be
adequately maintained and operated in accordance with its design specifications.
Furthermore, this MUST criterion assumes that only raw water delivered through
BFC, pumped from Boulder Reservoir, or conveyed directly from Carter Lake
through a dedicated pipeline will be utilized at BRWTF.
2. Water Rights Portfolio Yield
Each candidate BRWTF multi-barrier water delivery alternative must be
capable of maintaining the current expected yield of the City's water rights
portfolio and must not reduce the current level of flexibility in selecting drinking
water sources from its water rights portfolio.
B. Desirable WANT Criteria
The Praject Working Group developed 28 decision model pertormance
criteria in five categories including finished water quality, source water, treatment
operations, risk, and environmental and public acceptance, as listed in the
following sections. These criteria are satisfied by the BRWTF multi-barrier water
delivery alternatives outlined in Chapter 5 to varying degrees.
~naszz.z~o 4-2 osnaioi
BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Chapter 4 - Decision Criteria
1. Finished Water Quality Criteria
Finished water quality WANT criteria related to each of the contaminant
barrier categories detailed in Chapter 3 were incorporated including pathogens,
disinfection by-products, organic micropollutants, manganese, taste and odor,
and inorganic contaminants, as listed in Table 4-1.
Table 4-7
Finished Water Quality Criteria for BRWTF
Multi-Barrier Water Delivery Alternatives
Criteria Comments
Pathogens What are the recent trends in microbial water quality in
BFC, Boulder Reservoir, and Carter Lake? How likely are
acute pathogenic contamination events in these raw water
sources? Are barriers sufficient to prevent pathogens from
passing through BRWTF at levels that could jeopardize
public health?
Disinfection Byproducts Which DBPs will be formed and at what levels? Can
source water as well as treatment controls be used to
minimize DBP formation?
Organic Micro-POllutants How significant is the potential risk of organic chemical
contamination during source water conveyance or storage?
To what extent can treatment processes mitigate acute or
chronic organic chemical contamination?
Manganese What is the extent and duration of seasonal manganese
mobilization? Can source water as well as treatment
controls be used to limit manganese concentrations?
Taste and Odor What is the extent and duration of seasonal taste and odor
episodes associated with algal blooms or manganese
mobilization? Can source water as well as treatment
controls be used to minimize objectionable tastes and
odors?
Inorganic Contaminants What is the potential for inorganic contamination during
source water conveyance or storage? Can source water as
well as treatment controls be used to mitigate inorganic
contamination?
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BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Chapfer 4 - Decision Criteria
2. Source Water PortFolio Criteria
Decision model pertormance criteria related to management of the City's
source water portfolio were identified, as listed in Table 4-2.
Table 4-2
Source Water Portfolio Criteria for
BRWTF Water Delivery Alternatives
Criteria Comments
Source Water Quality Consistency What is the extent of seasonal and short-term source
water quality fluctuation to BRNIfF? Do these
fluctuations impact treatment at BRWTF and for how
long?
Water Rights Yield What is the availability of raw water for direct use? Is the
ability to manage stored reservoir water throughout the
year and during droughts maximized? Can water rights
yield be increased through enhanced water management
or capacity of facilities?
Portfolio Flexibility How many options are available for delivering raw water
to BRWTF? How difficult is it to switch water sources in
response to changing conditions? Are there seasonal
limitations on use of raw water sources?
Availability of Raw Water Delivery What is the expected reliability of infrastructure for raw
Faciiities water delivery to BRWfF? What are the capacity
limitations of these delivery methods? Are their
restrictions on the use of water delivery infrastructure due
to external factors that affect operations or water quality?
iaaszz z~o 4-4 osnaio~
BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Chapter 4 - Decision Criferia
3. Water Treatment and Operations Criteria
Decision model performance criteria related to water treatment and
BRWTF operations were identified, as listed in Table 4-3.
Table 4-3
Water Treatment and Operations Criteria for BRWTF Water Delivery Alternatives
Criteria Comments
Worker Safety What types and amounts of treatment or cleaning chemicals that staff
will be exposed to? What are the durations of these exposures? Will
staff be exposed to high voltage electrical shock hazards? Are
physically intensive maintenance procedures such as cleaning intake
grates required?
Process Flexibility What is the maturity and robustness of treatment technologies? Is the
number of treatment process technologies required to provide required
contaminant barriers minimized?
Process Reliability Is raw water delivered with consistent quality and flow? Can
consistent year-round treatment be provided with minimal process
failure?
Process Redundancy Are multiple barriers provided for contaminant categories of concern?
Is back-up capabiliry provided for critical treatment operations?
Maintenance Can all maintenance be pertormed by City staff or will an outside
contractor be required? Will routine replacement of consumable items
such as lamps or membranes be required?
Staffing What are the levels of staffing and supervision required? What levels
of expertise and certification are required?
Residuals Processing What are the quantities and characteristics of residuals produced by
new treatment processes? Wili residuals disposal require special
environmentai permitting?
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BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Chapter 4 - Decision Criteria
4. Risk Criteria
Decision model performance criteria associated with risk of source water
contamination, adverse impact of additional regulatory requirements on BRWTF
operations, infrastructure vulnerability, and chemical usage and delivery were
identified, as listed in Table 4-4.
Table 4-4
Risk Criteria for BRWTF Water Delivery Alternatives
Criteria Comments
Acute Contamination What is the potential for acute or "slug-loading"
of contaminants that could disrupt or disable
water delivery from BRWTF either temporarily
or long term? Is there potential for undetected
breakthrough of these contaminants?
Chronic Contamination What is the risk associated with non-point
contaminant sources in BRWTF raw water
supplies that could pose a threat to public
health? Are these contaminants difficult to
remove or inactivate through treatment?
Adaptability to Change What is the risk to public health associated
with potential near- and long-term source
water quality degradation? What is the
potential for future regulatory non-compliance?
Infrastructure Vulnerability What is the likelihood that damage to
infrastructure could impede purveyance or
treatment of the potable water supply?
Consumable Delivery/Usage Are there consumables such as process
specific chemicals, membranes, or lamps that
would impede treatment or public health
protection if delivery was interrupted? To what
extent are alternate sources of these critical
treatment consumables available?
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BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Chapier 4 - Decision Criteria
5. Environmental and Public Acceptance Criteria
Decision model pertormance criteria associated with environmental and
public acceptance issues specific to BRWTF were identified, as listed in
Table 4-5.
Table 4-5
Environmental and Public Acceptance Criteria for BRWTF Water Delivery Alternatives
Criteria Comments
Adjacent Land Use Compatibility Are there critical wildlife habitats, archeologically sensitive,
or historically significant lands adjacent to conveyance
structures? What impact might adjacent agricultural,
industrial, commercial, recreational, and residential tracts
have on conveyance?
Finished Water Uniformity How uniform is finished water quality across the
distribution system? Does finished water from BRWTF
meet City water quality goals?
Construction What are the land area footprint and associated
restoration requirements? Will extensive underground
excavation and associated materials handling be
required?
Consumer Confidence What is the level of consumer confidence with finished
water delivered from BRWTF?
Permitting Are there sensitive environmental or public acceptance
issues that would make required permitting difficult? What
measures are available to mitigate these concerns?
Energy Requirements What are the operational energy requirements and what
are their secondary environmental effects? Is there
potential for renewable energy generation?
~aaszzzio 4-7 osnsio~
BRWTF INTEGRATED SOURCE WATER AND TRE'ATMENT STUDY
Chapfer 5 - MWti-Barrier Altemafives
Chapter 5
Multi-Barrier Approach Alternatives
The integration of source water protection and treatment technologies into
multi-barrier water delivery approaches for BRWTF is detailed in this chapter.
Additional conceptual improvements recommended in the Phase I Source Water
Protection Study and Predesign Report including full containment from Carter
Lake to BRWTF, UV light disinfection, membrane filtration, ozone, and GAC were
considered here. Barriers for microbial pathogen control listed in the LT2ESWfR
Microbial Toolbox (Table 3-4) were also considered in this study. However, not
all of the City's drinking water quality goals were fully satisfied by all multi-barrier
water delivery alternatives evaluated, primarily due to compelling economic
considerations.
A. Conceptual Improvement Screening
Conceptual improvements that could be included in a multi-barrier water
delivery alternative at BRWTF were screened for applicability based on several
factors including integration with the existing treatment process train, probable
pertormance, and economic considerations. Potential conceptual improvements
were evaluated based on their ability to address one or more of the contaminant
barriers identified in Chapter 3 including microbial pathogens, DBPs, organic
micropollutants, manganese, taste and odor, and TDS and sulfate. The general
strategy of the screening process was to give greater consideration to conceptual
alternatives that where possible addressed more than one contaminant barrier,
thereby minimizing the number of conceptual improvements and complexity of
proposed multi-barrier water deliver alternatives.
1. Source Water Protection
Futl containment from Carter Lake to BRWfF was the onty source water
protection improvement considered in this study. Other strategies such as large
scale improvements to stormwater diversion along BFC or around Boulder
iaaszz.z~o 5-1 asnaio~
BRWTF 1NTEGRATED SOURCE WATER AND TREATMENT STUDY
Chapter 5 - Multi-Barrier A/ternatives
Reservoir, BFC road crossings, and hydraulic structures were not recommended
in the Phase I source water protection study, and were beyond the scope of this
study.
2. Prefiltration
Prefiltration options in the LT2ESWTR Microbial Toolbox, including pre-
sedimentation, two-stage lime softening, and bank filtration, receive low
inactivation/removal credit were not selected for inclusion in multi-barrier
alternatives. These treatment processes could provide an additional minimal
barrier for pathogens, but would not generally provide substantial additional
barriers for other contaminant categories. Because of the mineralized soils that
contribute to manganese and TDS increases while raw water is held in Boulder
Reservoir, bank filtration could even lead to raw water quality degradation.
3. Treatment Performance
Combined filter effluent and individual filter effluent pertormance credit
was considered an effective component of any multi-barrier treatment alternative.
These options assign additional Cryptosporidium log-inactivation/removal credit
based on maintaining filter turbidity levels below target values, thus require no
additional treatment processes. BRWTF has a treatment process optimization
program in place, so additional contaminant barrier credit based on
demonstration of further enhanced performance is likely, and was considered in
this study.
4. Additional Filtration
Additional filtration technologies including bag or cartridge filters, second
stage granular media filtration, and slow sand filtration were not included in multi-
barrier water delivery alternatives evaluated in this study. As with the prefiltration
options previously discussed, these additional filtration options would provide
only marginally increased log-inactivation/removal credit for Cryptosporidium,
and provide little in the way of additional barriers for other contaminant
categories. The hydraulic profile of the existing BRWTF would also not
accommodate additional filtration without substantial supplemental pumping,
increasing 0&M costs. The limited benefit of these additional filtration to finished
iaaszz.z~o 5-2 asnaio~
BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Chapter 5 - Mulfi-Barrier Aifernatives
water quality of the well designed and operated full-conventional treatment
provided by the existing BRWTF were not viewed as sufficient to justify the
associated large capital cost, increased O&M costs, and additional filter
backwash/cleaning requirements. However, due to the relatively high log-
removal credit possible with low-pressure membrane filtration, it was included as
a treatment process option in the BRWTF multi-barrier water delivery alternatives
evaluated.
5. Oxidationllnactivation
Chemical oxidation can potentially provide additional barriers for microbial
pathogens, DBPs, organic micropollutants, manganese, and objectionable tastes
and odors, depending on the oxidant used and its point of application. Addition
of chlorine dioxide for DBP, manganese, and taste and odor control is included in
the City's mid-term improvements plan, and is therefore assumed as part of the
baseline treatment for the long-term improvements evaluated here. Ozone was
also evaluated in this study because of its superior pertormance for taste and
odor control, ability to oxidize many organic micropoilutants, and additional
pathogen inactivation. UV disinfection was also evaluated due to its superior
disinfection performance for bacteria, viruses, and protozoan pathogens. These
treatment processes result in relatively low headloss, simpiifying their integration
with the existing hydraulic profile at BRWTF.
6. GAC Adsorption
Granular activated carbon was evaluated in this study based on additional
barriers for DBPS, organic micropollutants, and objectionable tastes and odors
that it may provide. Although GAC adsorption has headloss restrictions similar to
the filtration technologies previously considered, the multiple potential finished
water quality benefits that it may provide were viewed as su~cient to warrant the
added complexity and cost of integrating this process into the existing BRTWF
hydraulic profile.
B. Grouping Conceptual Improvements into Alternatives
Candidate multi-barrier approaches were developed for BRWiF by
combining conceptuai improvements that address identified drinking water quality
iaaszzz~o 5-3 osnaio~
BRWTF lNTEGRATED SOURCE WATER AND TREATMENT STUDY
Chapter 5 - Mu1fi-Barrier Alternatives
vulnerabilities in source water conveyance to and treatment at BRWTF. Only
those conveyance and treatment barriers that were selected in the screening
process previously described were included in BRWTF multi-barrier alternatives.
The combination of conceptual improvements selected for each delivery
alternative was based on providing process redundancy and operational
continuity at BRWTF.
Not all possible combinations of screened barriers were included in
alternative evaluations, but each screened barrier was incorporated in at least
one water delivery alternative. The multi-barrier delivery alternatives developed
for this study would produce finished water that meets all current state and
federal drinking water standards; however, it is important to note that not all of
these alternatives continuously meet the City's drinking water goals as discussed
below.
1. BFC and Boulder Reservoir Seasonal Delivery Alternatives
Five water delivery alternatives that provide seasonal raw water delivery to
BRWTF through BFC or by pumping from Boulder Reservoir were developed, as
shown schematically on Figures 5-1 through 5-5. Each of these delivery
alternatives is based on the existing conventional treatment at BRWTF and
residual disinfection with free chlorine. In addition, chlorine dioxide preoxidation
added as part of the ongoing mid-term improvements program was also
assumed.
. Alternative 1: This water delivery alternative incorporates
preoxidation with chlorine dioxide followed by full conventional
treatment and free chlorine disinfection. A centralized contact
basin for preoxidation contact time is included to allow use of both
BFC and Boulder reservoir raw water sources. Presedimentation
for turbidity and suspended solids control would also be provided
by the preoxidation contact basin, but because no coagulant would
be added prior to basin contact no credit towards Cryptosporidium
treatment would be provided. Residual chlorine dioxide and
chlorite would be quenched by ferrous sulfate addition prior to
coagulation.
This barrier combination serves as the baseline BRWTF
multi-barrier water delivery alternative. This baseline alternafive
would not meet the City's wafer qcrality goals with respecf fo
144922.210 ~J-4 06118l07
BFC/BR
~Mid-term Improvement
BLACK & VEATCH
r building auy~~~dof d"rfference ~
ENEflGY WATFR INFORMATION GOVERNMENT
Mix
Dissolved Air
Floatation
Granular
Media
Filtration
City of Boulder, Colorado - Multi-Barrier Approach Study
Figure
Alternative 1: Boulder Feeder Canal/Boulder Reservoir Seasonal Delivery 5-1
with CIOZ Pre-oxidation
Coagulant,
Polymer
BFC/BR
Pre-oxidation Flash Flocculation Dissolved Air
Mix Floatation
Mid-term Improvement
~-------------=~-----------~
~ Long-term Improvement ;
~ NaOCI
~ ~
~ ~
~ ~
~
~ ~
~ ~
_ ~ ~
, ~
~ ~
~ ~
~ ~
Granular ~ UV ~ Clearwell
Media ~ Disinfection~
Filtration ~---------~
- BLACK & VEATCH City of Boulder, Colorado - Multi-Barrier Approach Study
QY buildingaWfl~Idotdifference• Figure
Alternative 2: Boulder Feeder CanaUBoulder Reservoir Seasonal Delivery 5_2
ENEAGY WATER INFORMATION GOVERNMENT Wltll CIO2 PCe-OXIdatIOl~ i~Cld UV DISICIfeCtlOn
Flocculation Dissolved Air
Floatation
H ~
Granular ~ GAC ; ; UV
Media ;Contac~;Disinfectio
------ --------
Filtration
I
, Clearwell
City of Boulder, Colorado - Multi-Barrier Approach Study
BLACK & VEATCH Figure
buildinqaWOrld~r~~~rre~~~,~~~~ q~ternative 3: Boulder Feeder Canal/Boulder Reservoir Seasonal Delivery
5-3
eti~R~Y LVAT[R INFORMATiON GOVERN^.tttdi with C102 Pre-oxidation, GAC Adsorption and UV Disinfection
~-------------------------~
; Long-term Improvement ;
BFC/BR
Coagulant,
Pre-oxidation Flash Flocculation Dissolved Air
Mix Floatation
~Mid-term Improvement
-----------------
~-------- i
~ Long-term Improvement ;
~--__-__'"_"NaOCI
~
~ ,
~ ,
~ ~
~ ~
~ - ~
~
~ ~
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; ~~~O~U ~ ; '~`~
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~------------
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,,
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v Pathogens ~ `! ~ ~:
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ollutan
~
Manganese ,:
' ,~
~~`~
~
~ Taste and ~
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~ Qdor ~
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~
~ TDS and
~ Sulfate
- BLACK & VEATCH City of Boulder, Colorado - Multi-Barrier Approach Study
Figure
~, 6uildingayypf~dofdifference°° Alternative 4: Boulder Feeder Canal/Boulder Reservoir Seasonal Delivery 5-4
ENERGY WATER INFORMATI6N GOVERNMEtJT with C102 Pre-oxidation and Submerged MFIUF
BFC/BR
Mid-term Improvement
~-------------------------i
~ Long-term Improvement ;
Flash
Mix
----------,
n, ~
Flocculation Dissolved Air ; Advanced ;
Floatation ; Oxidation ;
Clearwell
- BLACK & VEATCH City of Boulder, Colorado - Multi-Barrier Approach Study
~ building ayyp~Idof dilierence° Figure
Alternative 5: Boulder Feeder CanaUBoulder Reservoir Seasonal Delivery 5-5
EtiEH~Y 1NATER ~~~FOR~,,a,~oN GOVEHK!.9eP:, with C102 Pre-oxidation and Advanced Oxidation
NaOCI
BRWTF 1NTEGRATED SOURCE WATER AND TREATMENT STUDY
Chapter 5 - Multi-Barrier Alfernatives
pafhogen control, nor would it meet finished water TDS and sulfate
goals when raw wafer is provided from Boulder Reservoir. No
effective barrier for organic micropollutant control is provided by this
alternafive.
Alternative 2: This alternative incorporates UV disinfection with the
barriers provided by Alternative 1. This delivery alternative would
not meet the City's TDS and sulfate water quality goals when
Boulder Reservoir was online, nor would it provide an effective
barrier for organic mrcropollutanf control.
Alternative 3: This alternative adds both GAC adsorption and UV
disinfection to the contaminant barriers provided by baseline
Alternative 1. This delivery alternative would nof ineet the City's
TDS and sulfate water quality goals when raw water was supplied
from Boulder Reservoir.
Alternative 4: This alternative utilizes the contaminant barriers in
baseline Alternative 1 with granular media filtration replaced by
submerged low-pressure membrane filtration retrofitted into the
existing filter boxes. This delivery alternative would not meef the
City's TDS and sulfate wafer quality goals, nor would if provide an
effective barrier for organic micropollutant control.
Alternative 5: This alternative adds ozone oxidation to the
contaminant barriers provided by baseline Alternative 1. This water
delivery alternative would nof ineef the City's water quality goals
with respect to pathogen control during cold weather operation at
BRWTF, nor would if ineet finished water TDS and sulfate goals.
2. Carter Lake Pipeline Delivery Alternative
Because a dedicated pipeline from Carter Lake for raw water delivery to
BRWTF provides barriers for each contaminant category except DBP control,
only one water alternative using this delivery method was developed, as shown
schematically on Figure 5-6. This alternative utilizes the existing conventional
treatment at BRWTF and residual disinfection with free chlorine. In addition,
chlorine dioxide preoxidation added as part of the ongoing mid-term
improvements program was also assumed.
,aas22z~o 5-5 osi~ara~
- - - - - - - - - Na
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Mid-term Improvement Mix Floatation Media
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~ r-------------------------i
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~ -------------------------~
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BLACK & VEATCH City of Boulder, Colorado - Multi-Barrier Approach Study
. buildingaWOFI(J~ta~ffe~e~~e°
Alternative 6: Carter Lake Pipeline Delivery with Figure
5-6
ENERGY WATER IfJFOR1.1A710N GO'JERNMENT CIOZ Pre-oxidation
~ BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Chapter 5 - Multi-Barrier A/ternatives
.
• Alternative 6: Carter Lake pipeline for turbidity, suspended solids,
manganese, taste and odor, organics, DBP, and inorganics control
followed by chlorine dioxide pre-oxidation for additional pathogen,
taste and odor, organics, and DBP control. This water delivery
alternative meets all the City's water quality goals, and provides at
least one barrier for each contaminant category evaluated.
3. Water Delivery Aiternatives Summary
The candidate water delivery alternatives outlined here integrate a range
of conceptual improvements with existing treatment processes to provide multi-
barrier approaches for drinking water treatment at BRWTF. Table 5-1
summarizes the barriers provided in each alternative for identified water quality
vulnerabilities.
As indicated in Table 5-1 BRWfF candidate water delivery Alternatives 1,
2, and 4 do not provide effective barriers for organic micropollutants and, and the
degree of organic micropollutant control provided by Alternative 3 varies with
GAC age. Only Alternative 3 provides TDS and sulfate in finished water that is
consistent with City drinking water goals. Alternatives 1, 2, and 5 also do not
satisfy the City's finished water quality goals for Cryptosporidium control, as
shown in Table 5-2.
~aaszzzio 5-6 asnaio~
~ BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
t Chapter 5- Multi-Barrier Alternatives
Table 5-1
Barriers for Water Quality Vulnerabilities at BRWTF
Alternative Pathogens DBPs Organic Mn Taste & TDS/
Micro- Odor Sulfate
ollutants
CIOZ CIOZ NB CIOZ CIOz NB
~ Conv. treat. Conv. treat. Conv. treat.
NaOCI
CIOZ CIOZ NB CIOZ CIOZ NB
2 Conv. treat. Conv. treat. Conv. treat.
UV
NaOCI
CIOz CIOZ GAC CIOZ CIOz NB
3 Conv. treat. Conv. treaL Conv. treat. GAC~'~
NaOCI GAC~3~
CIOz CIOZ NB CIOZ CIOz NB
4~~~ Conv. treat. Conv. treat. Conv. treat.
NaOCI
CIOz CIOZ AOP CIOZ CIO2 NB
5 Conv. treat. Conv. treat. Conv. treat. AOP
AOP AOP AOP
NaOCI
Pipeline CIOZ Pipeline Pipeline Pipeline Pipeline
CIOz~z~ Conv. treat. CIOZ~z~ CIOz~Z~
6 Conv. treat.
NaOq
Abbreviations:
CIOZ - chlorine dioxide, Conv. treat - conventional treatment (coagulation, flocculation, plate
assisted sedimentation, filtration), NaOCI - free chlorine, NB - no barrier, UV - ultraviolet light
disinfection, GAC - granular activated carbon adsorption, AOP - advanced oxidation process
(ozone/HZOz).
~'~Low pressure membrane filtration (MF/UF) instead of granular media filtration.
~Z~Partial barriers for pathogen and taste and odor control and robust barriers for DBP and
manganese control.
~3~Partial barriers for organic micropollutants and taste and odor and robust barrier for DBP control.
~aaszz.z~o 5-7 osnaio~
BRWTF INTEC~RATED SOURCE WATER AND TREATMENT STUDY
Chapter 5 - Multi-Banier Alternatives
Table 5-2
Microbial Pathogen Barriers for BRWTF Delivery Alternatives
Barrier Cryptosporidium Giardia Viruses
Conventional Treatment 3.0 2.5 2.0
Combined Filter
Performance
0.5
0.5~'~
-
Individual Filter
Performance
0.5
0.5~'~
-
Chlorine Dioxide 0.02/0.06 0.67/1.55 0.96/2.39
Ozone 0.52/1.60 12.49/31.55 26.64/66.60
Free Chlorine - 0.54/121 12.33/30.15
UV Disinfection~5~ 4.0 4.0 0.5
Pipeline~fi~ 1.5 1.5 -
Alternative Cryptosporidium Giardia Viruses
~ 4.02/4.06 4.71/629 15.29/34.54
2 8.02/8.06 8.71/10.29 15.79/35.04
3 8.02/8.06 8.71/10.29 15.79/35.04
q 5.52/5.56 6.71/8.29 15.29/34.54
5 4.54/5.66 17.20/37.84 41.93/101.1
g 5.52/5.56 621/7.79 16.79/36.04
City Goal 5.0 4.0 5.0
~'~Assumes same log-removal as for Cryptosporidium because Giardia is substantially
larger.
~Z~LT2ESWTR log-inactivation credit: 1 mg/L chlorine dioxide residual, 10 min. contact.3°C
and 15°C.
~3~LT2ESWTR log-inactivation credit: 1 mg/L ozone residua~, 10 min. contact, 3°C and 15°C.
~4~LT2ESWTR log-inactivation credit: 1 mg/L free chiorine residual, 10 min. contact, 3°C and
15°C.
~S~LT2ESWTR log-inactivation credit, UV dose 40 mJ/cm2, no temperature dependence.
~fi~Cryptosporidium and Giardia log-removal set equal to equivalent log-removal based on
ratio of historical bacterial concentrations in BFC and Carter Lake.
~aaszzz~o 5-8 osnsio~
BRWTF lNTEGRATEO SOURCE WATER AND TREATMENT STUDY
Chapter 6 - Performance Evaluation
Chapter 6
Non-Economic Performance Evaluation
The relative performance of multi-barrier water delivery alternatives
developed in Chapter 5 was evaluated using the K-T~ decision analysis
procedure outlined in Chapter 1. The complete non-economic performance
decision model including decision statement, criteria developed in Chapter 4, and
multi-barrier water delivery alternatives developed in Chapter 5 is shown on
Figure 6-1. Each water delivery alternative was ranked by its ability to satisfy the
non-economic performance criteria relative to all other alternatives.
A. Non-Economic Performance Criteria Weighting
The set of non-economic pertormance criteria developed in Chapter 4
were evaluated for their relative importance in selecting a multi-barrier water
delivery alternative for BRWTF. City staff assigned each performance criteria a
weight between 1 and 10, with the highest value for the most important criteria.
An ad hoc City staff committee (BRWTF Multi-Barrier Project Working Group)
representing drinking water quality, water resources, operations, and senior
management functions held a series of informal meetings and communications to
develop a preliminary set of performance criteria weights based on the collective
expertise and experience of the committee members. These preliminary criteria
weights were formalized based on the dialog of a workshop held on
December 14, 2006 between working group members and B&V. Table 6-1 lists
the relative weights assigned to each decision criteria.
As part of the K-T~ decision analysis process, the weight assigned to each
criterion was normalized such that the sum of normalized criteria weights is equal
to 1.0. Normalized criteria weights are termed priorities, as shown in Table 6-1.
It should be noted that this normalization process does not change the relative
importance of each criterion weight in determining water delivery alternative
scores.
~aaszz.z~o 6-1 osnsia~
°~. ~ e~~ ~i~
~ .~: ~ -~ . ~~>- ~
. .. ---__._.__.......__ _ ------------_ ____.____.________ ~. _----------___ __. ------------_.._.
.__ ._. _
.~ r :~,~~__:--_- _-- _ _. ._ ,~_..~......,-.,,n..,__{~,___._..,_,- -____,-w
City of Boulder, Colorado - Multi-Barrier Approach Study
Q BLACK & VEATCH Figure
; building aWOr~~(ord~ne~a~~e~ K-T~ Decision Analysis Model for BRWTF Multi-Barrier Approach 6-1
ENERqY WATEfl INPUPMATIUN 60VERNMENT Water Delivery Alternative Selection
BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
~a Chapter B- Performance Evaluation
Tabie fi-1
BRWTF Pertormance C nteria Wei ghls antl Water Delivery Altemative Scores
Model Weighta Alternative Ranking Againa! Crkeria
Decision Statement Criteria Weights Pdorities Alt 7 Alt 2 Alt 3 Alt 4 Alt 5 Alt 6 Albrnatives:
Select a MNb-Bamer Water ~elrve PaNogens 10 OA56 2 10 10 10 3 6 Alt i BFG/BR w/ CI02
Approach for BRVJrF Dismfection Byprotluds 7 0.039 9 9 9 9 10 9 Alt 2 BFC/BR w/ q02 and UV
Organ¢ Micropollu~anls 6 0.033 2 3 7 2 10 8 AI~ 3. BFC/BR w/ CI02, GAC antl UV
Inorgamc Micropollutanls 4 4U22 6 6 6 6 8 10 Alt 4 BFC/8R w/ CI02 and MFNF
Manganese 6 0033 8 8 8 8 8 10 A115. BFC/BRw/CI02antlA0P
TesteandOdor 6 0033 5 5 7 5 10 8 A118. CLPw/CI02
TDS anG Suttale 6 0.033 3 3 3 3 3 10
Consislency 8 0.033 2 2 2 2 2 10
WaterRightsVield 10 0.056 5 5 5 5 5 10
. PoMOlio Flexibiliy 8 0.049 5 5 5 5 5 10
Availebility 9 0.050 5 5 5 5 5 10
Wo~cerSafety ~0 0.058 10 7 6 6 6 10
Process Flexibility 6 0.033 6 8 8 8 10 6
Process Reliability 9 0.050 7 6 5 6 6 10
Process Retluntlanry 9 0.~50 6 8 9 6 10 10
Maintenence 3 0.017 10 7 4 B 6 10
SlaKng 3 0.017 8 7 7 9 5 10
ReslGUals Disposal 5 0.028 7 7 5 5 5 10
Acute Contamination 10 0.058 3 3 3 3 3 10
Chron¢ Contaminabon 10 0.058 2 5 7 5 8 10
AdaptabilitytoChange 9 0.044 2 5 7 5 8 10
Inf~asWCtureVulnerability 2 0.011 4 4 4 4 4 10
Consumeble DelneryNSage 1 0.006 10 8 5 4 4 10
Atl~acen~ Land Use Compehbiliry 8 0.044 4 4 4 4 3 10
System-WtleWaterUniformity 3 0.017 3 3 3 3 3 10
Consimcfion 7 0006 10 7 4 7 6 4
Consumer Con(tlence 8 0.044 6 ~ 10 ] 7 10
Permitting 7 0.006 10 8 6 8 8 fi
Ener yRe uiremen~s 5 0028 5 3 3 4 2 10
0.572 0.57J 0.806 0.5% 0.803 0.9C3 Altarnative Pertormance Scores
iaaezz z~a 6-2 ansroi
BRWTF lNTEGRATED SOURCE WATER AND TREATMENT STUDY
Chapter 6 - Performance Evaluation
B. BRWTF Multi-Barrier Alternative Performance Scores
The multi-barrier alternatives developed in Chapter 5 were ranked against
the weighted decision criteria listed in Table 6-1. B&V established the relative
pertormance of each water delivery alternative against each decision criterion in
turn by assigning scores between 1 and 10, with the highest value for the
alternative(s) that best satisfied the intent of the criterion. It is important to note
that assigning a score of 10 to an alternative for any given criterion does not
imply that the alternative satisfies the criterion perfectly, but rather that it most
closely satisfies the intent of the criterion. Remaining alternatives were assigned
lower scores based on their ability to satisfy the given criterion relative to the
alternative that best satisfies that criterion.
The general approach taken in ranking BRWTF water delivery alternatives
against each criterion was that wherever possible prevention of contamination
during raw water delivery to BRINTF is a superior strategy to subsequent
treatment at BRWTF. The working group developed a preliminary set of
guidelines for scoring alternatives against each criterion, as listed in Appendix 2.
Minor changes discussed in a workshop held January 18, 2007 with the project
Working Group and B&V were incorporated with the preliminary guidelines to
formalize the multi-barrier water delivery scoring process. Worksheets used
during BRWTF multi-barrier water delivery alternative scoring are given in
Appendix 2.
In the K-T~ decision analysis process performance scores for each
alternative are calculated as the sum of the products of decision model criteria
priorities and each set of respective alternative scores. These performance
scores are expressed on a scale of 0 to 1, with higher values indicating better
alternative performance. As shown in Table 6-1, non-economic performance
scores for the BRWTF water delivery alternatives evaluated in this study were
clustered between 0.5 and 0.6 for all but Alternative 6, which had a performance
score of 0.942.
C. Alternative Performance Sensitivity Analysis
The non-economic analysis pertormed here indicates that Alternative 6 is
the highest ranked BRWTF multi-barrier water delivery alternative, followed by
Alternatives 1 through 5 with non-economic performance scores that were
iaaszz.zio 6-3 osnsio~
BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Chapter 6 - Performance Evaluation
grouped in a substantially lower range. The sensitivity of this alternative ranking
to the criteria weights assigned was evaluated using the sensitivity analysis
feature of the Criterium DecisionPlus~ software package used to pertorm
decision analysis calculations. The change in each decision model criteria
weight required to alter the ranking of alternatives was determined, as illustrated
graphically in Figure 6-2 for the Pathogens criterion. In this figure, the dashed
vertical line shows the criterion weight assigned by the Project Working Group,
and the vertical solid red line indicates the critical priority value (critical
normalized weight) required to alter the BRWTF water delivery alternative
ranking. Thus, if the Pathogens criterion assigned priority value of 0.056 were
increased to 0.49 or greater then Alternative 3 would be the highest ranked
alternative. However, the Pathogens criterion was assigned the maximum
weight of 10, so a critical priority value of 0.49 would correspond to a criterion
weight substantially greater than 10 (161 in this case). Because adjusting any
assigned criterion weight to a value outside the 0 to 10 range used in the
decision analysis procedure would be meaningless, the ranking of BRWTF multi-
barrier water delivery alternatives was not sensitive to the weight assigned to the
Pathogens criterion. Similar analysis of all other decision model criteria indicates
that the ranking of alternatives was not sensitive to the weight assigned to any
criterion.
iaaszz zio 6-4 osnsio~
~ k~R" .~ "ri' . ~ A~4 ~. '~.
P!I#IE Pf~Wt 'k~~{1Y ~~S 4kiCf~.;>:$~.~5 ,i
~rat
Altematives
AF 6. CLP w/ Ci~2
AN3 6FC/BRw~lC102.GA
AG7 BFCIBRwlC~2an
Ak4 BfC/BRw/C~2an
Ak 5 BFGBR w! CI02 an
uu
pipriry value
lU
Temp~`aha:
C A9(aul cd range-0S)
CurreM Value
0 06[GAica~
Q BLACK & VEATCH City of Boulder, Colorado - Multi-Barrier Approach Study
~ buildingayyp~~~jotdifference~ F19U~@
BRWTF Multi-Barrier Water Delivery Alternative Ranking Sensitivity: g_2
ENERGY WATEfl INFOPMAT~ON GOVERNMENT Pathogens Criterion
BRWTF 1NTEGRATED SOURCE WATER AND TREATMENT STUDY
Chapter7- Economic Evaluafion
Chapter 7
Multi-Barrier Approach Economic Evaluation
The relative economic merit of multi-barrier water delivery alternatives
developed in Chapter 5 was evaluated based on a life-cycle cost present value
analysis that included capital, O&M, and project financing costs.
A. Economic Evaluation Principles and Parameters
The economic analysis pertormed in this study was based on applying a
common set of unit process and O&M costs to each BRWTF multi-barrier water
delivery alternative. The Class 4 planning level cost opinions presented here
reflect use of standard engineering practices and were prepared without the
benefit of detailed engineering designs. As defined by The Association for the
Advancement of Cost Engineering, Class 4 cost opinions of this type are
generally considered to have an accuracy range of plus 50 to minus 30 percent.
Any actual project cost would depend on current labor and material costs,
competitive market conditions, final project scope, bid date, and other variable
factors. These cost opinions are perhaps best used to compare relative multi-
barrier water delivery alternative costs, rather than actual project costs.
A 30-year life-cycle was assumed for each water delivery alternative
evaluated consistent with industry standard expected service lives for major
drinking water treatment equipment. Because the expected useful life of large
diameter subterranean transmission mains is considerably longer than 30 years,
the residual value of the Carter Lake Pipeline beyond this time was credited to
the net present value cost opinion for Alternative 6. Useful life for large diameter
welded steel pipe of the type proposed for the Carter Lake Pipeline was
conservatively estimated using representative survival functions to be 70 years
(Quantifying Future Rehabilitation and Replacement Needs of Water Mains,
AINWARF, 1998). Other common economic analysis parameters used include a
2007 baseline, an 0&M inflation rate of 4 percent, a loan interest rate of
6 percent, and a present worth factor of 4 percent.
iaaszz.z~o 7-1 osnsio~
BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Chapter 7 - Economic Evaluation
B. Capital Cost Opinions
Capital cost opinions include material and construction estimates for
process equipment and basins, any additional structures needed to house
process equipment, electrical service, instrumentation and control, site work,
yard piping, and general contracting. Engineering, legal, and administrative
expenses were estimated to be 20 percent of the material and construction cost
subtotal. Similarly, a contingency factor of 25 percent was applied to the material
and construction subtotal. Present value life-cycle capital cost opinions were
generated using the economic parameters given above for a firm capacity of
16 mgd at BRWTF.
The capital cost opinions for BRWTF multi-barrier water delivery
alternatives evaluated as part of this study are given in 2007 dollars as shown in
Figure 7-1, and the associated life-cycle present value of these capital costs are
given in Figure 7-2. As shown in Figure 7-1, the capital costs varied widely
between no additional capital expenditure for Alternative 1 and $22M for
Alternative 3. The present value of these capital costs are slightly higher due to
project financing at 6 percent interest over the 30-year project life-cycle. The
present value of Alternative 6 is substantially less than its estimated cost in 2007
dollars because the residual value of the pipeline beyond 30 years was credited
to this alternative. It should be noted that these capital costs estimates are in
addition to any capital costs related to planned mid-term improvements including
chlorine dioxide pre-oxidation and finished water pH adjustment.
C. O&M Cost Opinions
O&M costs were determined for the 30-year life-cycle used for economic
evaluation purposes. These O&M estimates included treatment chemical, other
consumables such as UV lamp and ballast replacement, GAC replacement,
pumping and other energy costs, and scheduled equipment maintenance. An
average daily flow rate of 5 mgd was used to calculate variable consumable and
energy O&M costs. This production rate was slightly higher than the 4.55 mgd
average daily flow in 2006 to account for future growth in the BR1/VTF service
area.
~aasz2z~o 7-2 osnaio~
$40
Alternative Source Barriers
1 BFC/BR CIOZ, conv. treat.
2 BFC/BR CIO2, conv. treat., UV
3 BFC/BR CIOZ, conv. treat., GAC, UV
4 BFC/BR CIOZ, conv. treat., MF/UF
~ $30 5 BFC/BR CIO2, conv, treat., AOP
~
.... 6 CLP Pipeline, CIOZ, conv. treat.
ti
O
°
N $21.92
$21.06
c
;F, $20
N
O
U
~ $13.22 $13.57
~
a
~j $10
$2.44
$0.00
$0
1 2 3 4 5 6
Alternative
City of Boulder, Colorado - Multi-Barrier Approach Study
BLACK & VEATCN Fi
gure
R 6uildi ngayyp(~~ord~re~e~~~•• Capital Costs for BRWTF Multi-Barrier Approach ~.q
ENENGV WATEP INF~BMATI~N GOVERNMFNT Water Delivery Alternatives in 2007 Dollars
$40
.-.
~
6f~
.~.
o $30
U
R
~
.Q
R
,V $20
0
m
3
R
>
~
~ $10
N
a~
L
a
$0
Alternative Source Barriers
1 BFC/BR CIOZ, wnv. treat.
2 BFC/BR CIOZ, conv, treat., UV
3 BFCBR CIOZ, conv, treat., GAC, UV
4 BFC/BR CIO2, conv. treat., MF/UF
5 BFC/BR CIOZ, conv. treat., AOP
$27.55 6 CLP Pipeline, CIOZ, conv. treat.
$16.62 $17.05
$11.34
$3.06
$0.00
1 2 3 4 5 6
Alternative
City of Boulder, Colorado - Multi-Barrier Approach Study
~ BLACK & VEA7CH Figure
buildingayypr~aotd~ne~B~~~- Present Value of Capital Costs for BRWTF Multi-Barrier Approach 7_2
ENEkGY WATEfl INFUBMATIUN GOVERNMENT Water Delivery Alternatives
BRWTF INTEGRATED SOURCE WRTER AND TREATMENT STUDY
Chapter 7- Economic Evaluation
Annual O&M cost opinions for BRWTF multi-barrier water delivery
alternatives evaluated as part of this study are given in 2007 dollars as shown on
Figure 7-3, and the associated life-cycle present value of these O&M costs are
given in Figure 7-4. Annual O&M costs for Alternatives 1, 2, and 6 were
clustered between $170k and $210k, with considerably higher values of $860k,
$420k, and $330k for Alternatives 3, 4, and 5. The higher annual O&M estimates
for Alternatives 3, 4, and 5 reflect costs associated with semi-annual GAC
replacement, membrane replacement and cleaning chemicals, and precursor
chemicals for advanced oxidation, respectively. The present value of these O&M
costs reflects an annual inflation rate of 4 percent, applied each year throughout
the project life-cycle. The additional O&M costs for chlorine dioxide preoxidation
and pH adjustment planned as mid-term improvements were include for all water
delivery alternatives.
D. Net Present Value Opinions
The total net present value cost opinions for BRWTF multi-barrier water
delivery alternatives were calculated as the sum of net present capital and O&M
costs, as shown on Figure 7-5. Water delivery alternative net present value
estimates varied widely between $5.2M a~d $53.4M, based largely on the
number and type of additional contaminant barriers. The comparatively lower net
present values for Alternatives 1 and 2 reflect the lack of an effective barrier for
organic micropollutants, and a less robust set of barriers for taste and odor
control. The comparatively higher net present values for Alternatives 3 and 5
reflect a premium required when organic micropollutant and taste and odor
contro4 are provided by treatment rather than source water protection, whereas
Alternative 4 has a higher net present value due primarily to membrane
replacement costs.
iaaszz.z~o 7-3 osna~o~
$1.0
Alternative Source Barriers
$0.86 1 BFC/BR CIOZ, conv. treat.
2 BFC/BR CIOZ, conv. treat., UV
^ 3 BFC/BR CIO2, com. treat., GAC, UV
~ $~,$ 4 BFC/BR CIOZ, conv. treat., MF/UF
~? 5 BFC/BR CIO2, conv. treat., AOP
ti 6 CLP Pipeline, CIOZ, conv. treat.
O
O
N
c $0.6
~
y
O
V $0.42
~ $0.4
~ $0.32
~
~
_ $0.21
$0.19
Q 2 $0.17
$0
.
$0.0
1 2 3 4 5 6
Alternative
City of Boulder, Cotorado - Multi-Barrier Approach Study
~L ACK & V~-TCH Fi
gure
r bailding ayyp~~dora~rre~a~~g- Annual O&M Costs for BRWTF Multi-Barrier Approach ~_g
ENERGY WATEfl IPIFqpMATIUN GOVEPNMEN7 Water Delivery Alternatives in 2007 Dollars
$30
.-.
~
~
rr
N
V $2~
~
~
O
w
0
a~
~
~
~ $10
c
m
N
~
a
~o
Alternative Source Barr'ers
$2rj,$] 1 BFC/BR CIOZ, conv. treat.
2 BFC/BR CIOZ, conv. treat., UV
3 BFC/BR CIOZ, conv. treat., GAC, UV
4 BFC/BR CIO2, conv. treat., MF/UF
5 BFC/BR CIOZ, conv. treat., AOP
6 CLP Pipeline, CIO2, conv. treat.
$12.63
$9.60
$6.22 $5.78
$5.20
1 2 3 4 5 6
Alternative
City of Boulder, Colorado - Multi-Barrier Approach Study
BLACK & VEATCH Figure
„ e~~ia~ns eworld~td~ne~e~~~•• Present Value of O&M Costs for BRWTF Multi-Barrier Approach 7_4
ENEftGY WATEfl INFOflMATi~N GOVERNMENT Water Delivery Alternatives ~
$70
Alternative Source Barriers
1 BFC/BR CIOZ, conv. treat.
$60 2 BFC/BR CIO2, conv. treat., UV
3 BFC/BR CIO2, conv. treat., GAC, UV
$53.41 q BFC/BR CIOZ, conv. treat., MF/UF
5 BFClBR CIO2, conv. treat., AOP
~ $50 6 CLP Pipeline, CIO2, conv. treat.
t~4
...
d
~
~ $40
>
_ $29.25
vi $30 $26.65
L
a
Z $20 $17.12
$9.2$
$10
$520
$0
1 2 3 4 5 6
Alternative
City of Boulder, Colorado - Multi-Barrier Approach Study
BL ACK & VEATCH Fi
gure
e 6uildin9ayyp~~~ard~ne~a~~g• Net Present Value of BRWTF Multi-BarrierApproach 7_5
ENERGY WA7Eft INFUflMAT~~N G~VERNMENT Water Delivery Alternative Selection
.. BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
~ Chapfer 8 - Preferred Alternative
Chapter 8
Preferred BRWTF Multi-Barrier Alternative
The non-economic performance score of each BRWTF multi-barrier water
delivery alternative was determined using the Kepner-Tregoe~ decision analysis
procedure. Economic evaiuation of each water delivery alternative was also
performed, based on the net present value of each alternative, which includes
capital costs, operation and maintenance costs, and project financing. This
chapter presents these non-economic performance and economic evaluations
together to provide a cost-performance comparison of BRWTF multi-barrier water
delivery alternatives. Based on a balanced assessment of source water quality
information, regulatory requirements, City drinking water quality goals, non-
economic pertormance scoring, and net present cost economic evaluations a
preferred BRWfF multi-barrier water delivery alternative is identified.
A. Cost-Performance Comparison
Non-economic performance scoring and economic evaluations of
candidate multi-barrier BRWTF alternatives were described in Chapters 6 and 7,
respectively. Because of the large variations in alternative performances and net
present values, these values are shown side-by-side to help assess the relative
benefits for each water delivery alternative, as shown in Figure 8-1.
B. Preferred BRWTF Water Delivery Alternative
Both performance and cost varies widely among the six BRWTF water
delivery alternatives evaluated. Considering source water quality information,
relative risk of source water contamination, regulatory requirements, City drinking
water quality goals, and operational flexibility 8&V believes that Alternative 6,
complete source water containment from Carter Lake to BRWTF with chlorine
dioxide preoxidation, is the most desirable and preferred alternative. Although
Atternative 6 does not have the lowest net present value among those evaluated,
it has a number of compelling benefits that are not provided by the other
alternatives including:
~nas22 2io 8-1 osnaio~
60
50
.-.
~
~ 40
a>
~
~
= 30
d
N
L
a 20
m
Z
10
0
0.942
O Net Present Value $53.41
^ Decision Score
0 606 0.603
0.573 0.554
0.512 $29
$26.
$17.
$9.
$5.
1.0
0.9
0.8
0.7
a~
0.6 v
~
0.5 0
.y
0.4 ~
0
0.3
0.2
0.1
0.0
1 2 3 4 5 6
Alternative
City of Boulder, Colorado - Multi-Barrier Approach Study
~ BLACK & VEATCH Figure
building ayy~pr~dof ditterence^ $-~
Cost-Performance Comparison for BRWTF Water Delivery Alternatives
ENEPCY WATEN INFUPMATION 40VERNMENT
BRWTF lNTEGRATED SOURCE WATER AND TREATMENT STUDY
Chapter 8 - Preferred Alternative
Of the BRWTF multi-barrier water delivery alternatives evaluated
here, Alternative 6 alone follows the century old paradigm of
drinking water treatment in that it treats the best available water
source with the simplest and most robust combination of
processes.
Alternative 6 has the best non-economic performance by a wide
margin. This alternative satisfied 22 of 28 criteria evaluated as well
or better than the other alternatives.
Alternative 6 is unique among those evaluated in that it alone
addresses the near and long term potential for continued
degradation of water quality in existing BRWTF sources due to
continued residential development, extensive agricultural land use,
and increasing recreational use. Although notable advances in
treatment technology have been made in recent years, contaminant
removal during drinking water treatment is still an imperfect
science. Thus, as has traditionally been the case, preventing
source water contamination provides a more robust barrier than
subsequent treatment as the first line of defense in protecting public
health.
Other regional drinking water providers also desire to use a
dedicated pipeline from Carter Lake for raw water delivery to their
facilities. Combining raw water conveyance to BRWTF with that of
other providers allows more efficient use of scarce regional water
resources.
Full containment of raw water conveyance from Carter Lake to
BRWTF would provide additional flexibility in managing the City's
water resources portfolio. Other water delivery alternatives require
seasonal storage of raw water in 8oulder Reservoir for use when
BFC in not in service. Year-round storage in Carter Lake would
remove the need to project annual seasonal storage required in
Boulder reservoir, and thus avoid the undesirable consequences
that result if seasonal Boulder Reservoir storage is substantially
overestimated.
Conveyance of raw water through a Carter Lake pipeline would be
consistent with the City's historical policy of protecting source water
quality by providing full containment from its other water sources.
~aaszz.zia 8-2 osnaio~
BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Chapfer 8 - Preferred Alternative
Full containment from Carter Lake to BRWTF would provide a
much more uniform raw water quality, substantially simplifying
treatment optimization and increasing treatment process reliability.
Alternative 6 is the only BRWTF water delivery approach that
provides at least one robust barrier for each contaminant category
considered in this study.
~aaszzz~o 8-3 osnaia~
BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Appendix 1- Cify Water Quality and Operational Goa/s
Goal: Provide Safe and Reliable Potable Water
Strate Aetion Measureble Criteria
Comply with all drinking water regulations. . Continue high quality treatment Achieve 100°!o compliance for all standards
• Evaluate DBP compliance forecast and
establish DBP reduction plan, if needed.
• Perform LT2 monitoring, establish treatment
bin, and install treatment as re uired.
Use best practices to maintain high quality treated . Jar test regularly BRWTP: Betasso WTP:
water. . Evaluate filter media on a regular basis • SCD: 0± 0.5 • SCD: 0
• Investigate problem filters when they become • Zeta Potential: 0--5 • Zeta Potential: -3
apparent • Settled Turbidity: < 1 • Zeta Alkalinity: >
NTU 90% of time 9.0 mg/L
sampling every 15 . Settled Turbidity:
minutes < 3.0 NTU
. Settled Turbidity: < 2 . Settled pH. 6.4 -
NTU at all times 6.8
• Start-up Filter Turb: <_ • Settled CI2: 0.5
0.3 NTU at end of 30 mg/L
minutes . Filter Run time: <
• Filter Turb: < 0.1 NTU 40 hours
in 95% of IFE 15 . Filtration Rate: 5
minutes samples; gpm/sf or 5 mgd
• Filter Turb: < 0.15 NTU max
at all times . Hydraulic
• Filter Particle Count: change/filter: <
<25/mL for particles > 1.0 mgd
2 µm in 95% of • Filter Rest Time:
. Filter Loading Rate: < 3 hours
5 gpm/sqft • Start-up Fiiter
• Filter Run Time: > 60 Turb: < 1 NTU
hours w/in 15 min of
. Filter Rest Before startup
Start-up: ? 3 hours • Filter turbidity: <
• Inactivation: > 95% of 0.15 NTU
~aaszz.zi o A.1-1 osn aio~
BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Appendix 1- City Wafer Quality and Operational Goa/s
minimum pertormance . Filter particle
measure count: < 25 total
• CIZ Dose: < 2.0 mg/L counts
• Combined filter • Combined filter
effluent CI2: 0.4 mg/L turbidity: < 0.1
NTU
• Combined filter
particle counts: <
25 total counts
• Combined filter
CI2: 0.1 m /L
Seek alternative methods to increase delivered . Implement necessary upgrades to the BRWTF BRWTF finished water: Betasso finished
water quality. to ensure a multi-barrier system. • pH: 7.8 t 0.2 water:
• Improve clarification treatment. • Alkalinity: 40 to 50 • pH: 7.5+ 0.2
• Partnership for Safe Water- Phase III mg/L CaCOa • Alkalinity: 45 + 3
• Implement the AWWA Standard for Water • Hardness: <60 ppm mg/L CaC03
Treatment Plant Operations and Management • Turbidity: < 0.1 NTU •
(G200-O5) • Sulfate: < 20 ppm • Turbidity: < 0.1
• Join AwwaRF (American Water Works . Sodium: 5-20ppm NTU
Association Research Foundation) . TDS: < 100 ppm •
• Conductivity: < 200 •
µmhos/cm •
• Temperature: < 20 °C •
• Fluoride: 0.9 + 0.1 •
mg/L •
• CIZ: 1.1+0.1 mg/L
Manganese: < 0.03 mg/L • Fluoride: 0.9 +
0.1 mg/L
• CI2: 1.2+0.1
m /L
• Improve disinfection Meet minimum daily control levels:
• 99.99% removal of Giar dia
• 99.999% removal of Cry ptospondium
• 99.999% removal of ent eric viruses
iaaszz.z~ o A.1-2 osnsio~
BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Appendix 1- City Wafer Quality and Operational Goals
Deliver similar and consistent finished water • Set uniform levels for water quality parameters. Maintain finished water:
quality from both plants. • Develop program to bring water from both • Hardness < 60 mg/L
plants into consistent range for measured • Alkalinity 40 to 50 mg/L
parameters. . pH: 7.8 ± 0.2
• Control pH and/or ORP of finished water. . Turbidity < 0.1 NTU
• Sulfate < 20 mg/L
• Sodium: 5-20 mg/L
• TDS < 100 mg/L
• Specific Conductance < 200 umhos/cm
• Temperature < 20 oC
• No detectable taste and odor
• Manganese < 0.03 mg/L
• Fluoride: 0.9 + 0.1 m /L
Maintain consistent water quality throughout the . Minimize effect of mixing regions by
distribution system. implementing consistent multiple-plant finished
water qualiry program
• Implement the AVWVA Standard for Distribution
System Operations and Maintenance (G200-
04
• Develop a monitoring program for the pH: 7.8 ± 0.3 at 95% of locations sampled monthly
distribution system and a plan for adjusting for total coliforms
water quality where necessary. Free CI2: 0.5 + 0.1 mg/L at 95% of locations
sam les monthl
• Investigate Pb/Cu corrosion behavior and No Lead and Copper Rule violations
status.
• Develop a bacterial regrowth action plan. Maintain heterotrophic plate count bacteria levels <
100 counts/mL in 95°/a of monthly distribution
s stem sam les
• Develop a plan to meet DBP criteria for Maintain locational running annual average TTHM
reduced monitoring under Stage 1 DBPR and and HAA5 levels less than 40 ug/L and 30 ug/L,
Sta e 2 DBPR. respectively.
• Develop a plan to maintain water quality in
distribution s stem reservoirs
iaaszz.zio A.1-3 osnaio~
BRWTF 1NTEGRATED SOURCE WATER AND TREATMENT STUDY
Appendix 1- City Water Quality and Operational Goa/s
Reinforce distribution system integrity Implement and maintain effective backflow
prevention program.
. Require mandatory installations for all new
construdion
• Create a retrofit program for existing
connections
. Require and pertorm an annual check of all
BFPs
. Require mandatory installation of BFPs for
temporary connections during construction
• Pertortn routine inspection of construction sites
to assure compliance
• Require mandatory BFPS for source water
hydrants
. Assess staffin needs for im lementation
• Ensure integrity of all distribution system Pass weekly inspection of all tanks to assure
stora e tanks. integrity.
Meet all customer demands during normal • Acquire adequate water rights Maintain
operations and critical demands during •> 20 years: No interruption of outdoor use
emergencies or droughts. •> 100 years: No interruption of outdoor use with
major loss
• 1,000 years: No interruption of indoor essential
use
Deliver sufficient raw water to treatment plants . Minimum storage: 3-5 MG
• Minimum source delivery to WTPs:
o Betasso - greater of 5 MGD or Zone 3
indooruse
o Boulder Reservoir - 5 MGD
Ensure daily reliable plant operations at design Implement plant maintenance management . Minimum production:
flows program o Betasso - greater of 5 MGD or Zone 3
indooruse
o Boulder Reservoir - 5 MGD
• Maximum production:
o Betasso - entire s stem demand:
~ aaszzzio A.1-4 osn am~
BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Appendix 1- City Wafer Quality and Operational Goals
internal use demand plus a margin of
safety (16 MGD)
o Minimize unscheduled shutdowns of
BRWfP
Meet daily demand fluctuations and maintain . Provide sufficient storage Maintain total storage:
minimum fre flow protection levels . Operate to meet demands and to optimize • Winter Daily: > 18 MG
water quality in the distribution system. • Summer Daily: > 28 MG
• Absolute Minimum: 5 MG
• Maintain zone-specific storage:
• Daily: >
• Absolute Minimum:
• Firm Yield Ca acit Re uirements b Zone:
Improve source water quality protection • Develop a source water protection rules • Hold routine weekly meetings of appropriate
• Implement source water reservoir management staff to make source water selection decisions
plans
• Continue source water monitoring program to
track water quality conditions temporally and
spatially
• Implementation of a mid-level intake at Boulder
Reservoir (completed 2005)
• Implementation of a manganese control
strategy using source management techniques
(e.g., in situ aeration)
• Improve communication and coordination for
source water selection
• Develop and communicate a Risk Index
• Coordinate with NCWCD to maximize flow
through Boulder Reservoir
• Determine best source based on treatability
and quality
• Coordinate with County Planning to ensure
watershed rotection in lannin rocess
Integrate public health risk factors into source • Develop a Public Health Protection Index
water and treatment management decisions. PHPI or Risk Index
i aaszzzi o A.1-5 osn aio~
BF2WTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Appendix 1- City Water Quality and Operational Goals
• Establish Stakeholder group to assist in PHPI
process
• Establish consensus of internal and external
decision-makers on the PHPI a lications.
Improve knowledge of emerging contaminant . Pertorm the monitoring program included in the • Volunteer for AwwaRF participation in research
occurrence Unregulated Contaminant Monitoring projects of interest
Regulation.
• Continue to track unregulated contaminants to
determine risk and evaluate monitorin need.
Goal: Provtde Res nsive Gustomer Service
Strete Action Measurable Criteria
Deliver aesthetically pleasing and safe water . Evaluate causes of past customer complaints Continuous decrease in water quality customer
• Develop program for system flushing complaint calls
• Implement program for customer response to
com laints
Disseminate water quality and utility information to . Update web site with:
the public o Summarized customer survey results
o Water quality "frequently asked
questions"
o Water quality data
• Distribute annual CCR
Identify areas of improvement for customer service . Participate in Qual Serve (AW1NA)
and utilit mana ement
Develop public education programs • Source water quality
• Source water rotection
Goal: O erate Cost Effectivel
Strat AcY1on Measurable Criteria
Establish utility rates that reflect water services . Complete economic analysis of rates
delivered to customers, including . Establish new water rates as appropriate
1. Quality
2. Volume
3. Education
4. Source management and protection
5. Demand mana ement
iaaszzzio A.1-6 asnaio~
~
~
BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Appendix 1- City Water Quality and Operafional Goals
6. Treatment
7. Distribution
Goal: Promote Environmental Stewardshi of our Natural Resources
Strate Action Measurable Criteria
Reduce total system demands . Implement and support the Board-approved Reduce total system demands as follows:
water conservation program "Comprehensive • Single Family: 6.22 MGD
Conservation Program" . Multiple Family: 4.94 MGD
• Commercial/Industrial: 6.16 MGD
• Municipal: 0.76 MGD
• Unaccounted-for-water: 1.25 MDG
• Total Demand: 19.4 MGD
Definitions:
Goal = End toward which effort is directed
Strategy = Blueprint, design, game plan, project, scheme
Action = Something done or effected
Criteria = Measurable standard on which a'ud ment or decision ma be based.
iaas22.zio A.1-7 osnaia~
BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Appendix 2- Decision Model Criteria and Alternafive Scoring
APPENDIX 2
DECISION MODEL CRITERIA AND ALTERNATIVE SCORING
inished Water Quality
-- Corrosion removed -- no significant difference among alternatives
-- Organic micropollutants and emerging contaminants combined
-- Mn, T&O, and TDS/SO42- added - significant difference among alternatives
ource Water
-- No changes to Boulder staff draft criteria of 01/03/07
Jater TreatmenUOps
-- Monitoring/remote sensing removed -- 0 weight assigned
-- Reliability/redundancy split into 2 criteria
-- Power interruption removed -- no significant difference among altematives
nviron./Public Accept
-- No changes to Boulder staff draft criteria of 01/03/07
~aaszz.zio A.2-1 osnaio~
BRWTF 1NTEGRATED SOURCE WATER AND TREATMENT STUDY
Appettdix 2- Decision Model Criteria and Alternative Scoring
Objectives and Criteria for a Multi-Barrier Approach to
Treated Water - Fall 2006
I. Musts for ALL Alternatives:
A. Meet Regulations
B. No loss of water yield
1. The City has a water rights portfolio and raw water system facilities
that are used to provide su~cient raw water to meet the City's needs in
accordance with adopted reliability criteria. The reliability criteria have
been used to define the level of water use restrictions that might be
needed for droughts with specified recurrence intervals to avoid
lowering of reservoirs below safe levels to the point that delivery of
water for essential health and safety needs is jeopardized. Any
alternative for raw water delivery needs to be capable of maintaining
the current expected level of yield of the City's water rights and must
not reduce the current level of flexibility in selecting water sources.
II. Finished Water Quality Criteria
A. Pathogens - Health issue. Disease causinp orpanisms.
1. A higher ranking will be given to those alternatives that best address
limiting the potential for public health impacts from pathogens.
Alternatives will be ranked by:
a. Source water vulnerability
1) Pathogen indicatorcounts
2) Potential for pathogen introduction
b. Treatment
1) Log removal and toof box - use regufatory limits
2) Potential for pathogens to pass through treatment process
2. Factors to consider
a. The intent of this criterion is to address pathogen risk by selecting
the best source water quality and/or treatment techniques
b. See attached source water quality table
B. Disinfection By-Products (DBPs) - Health issue. Formed when
disinfectant (i.e. chlorine) combines with naturallv occurrinp and/or other
compounds in the water or from the disinfectant itself.
1. A higher ranking will be given to those alternatives that minimize DBP
formation andlor reduce DBP's. Alternatives will be ranked by
i aaszz zi o A2-2 osn eio~
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~
a. Source water
1) Precursors (TOC)
2) Chlorine dosage
b. Treatment
1) Removal
2) Oxidation and/or absorption of precursors
2. Factors to consider
a. The intent of this criterion is to address the potential for DBP
formation
b. Similar average TOC values (3.5 mg/L) are present in Boulder
Reservoir, BFC and Carter Lake
c. See attached source water quality table
C. Micro-organic Compounds - Health issue. Man made carbon
compounds.
1. A higher ranking will be given to those alternatives that provide the
best protection against the introduction and/or removal of organic
compounds (ie. pesticides, hydrocarbons) and limits the risk of organic
compounds passing on to the consumer in the finished water.
Alternatives will be ranked by:
1) Source water vulnerability to organic compounds
b. Treatment
1) Contaminants passing through treatment
2) Absorb organic compounds
2. Factors to consider
a. The intent of this criterion is to evaluate the potential for man made
organic compounds to enter the source water and possibly be
passed on to consumers
b. Potential for organic compounds to enter the source water-
intentional, accidental or due to recreation activities
c. Standard maintenance activities that can introduce organic
compounds
d. Potential for non-point source contributions due to precipitation
events and agricultural return inflows
e. Available source water dilution
D. Inorganic Compounds - Health issue. Non-natural toxic chemica/s such
as arsenic and cyanide.
1. A higher ranking will be given to those alternatives that provide the
best protection against the introduction and/or removal of toxic
inorganic compounds. The alternatives will be ranked by:
a. Source water vulnerability to inorganic toxic compounds and
chemicals
b. Treatment
~aaszzzio A.2-3 osnsio~
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~ Appendix 2- Decision Model Criteria and Alternative Scoring
2. Factors to consider
a. The intent of this criterion is to evaluate the potential for non-natural
and natural toxic inorganic compounds to enter the source water
and possibly be passed on to consumers in the finished water.
E. Emerging Contaminants - Health issue. Unreoulated contaminants that
pose a health risk. Examples are pasoline additives. microbes smaller
than Crvptosaoridium that are resistant to chlorine. nharmaceutical druqs,
new disinfection-bv-products and new pesticides.
1. A higher ranking will be given to those alternatives that provide the
best protection against the introduction and/or removal of emerging
contaminants to the source water and being passed on to consumers
in the finished water. The alternatives will be ranked by:
a. Source water vulnerability
1) Gasoline additives
2) Microbes smailer than Cryptosporidium that are resistant to
chlorine
3) Pharmaceutical drugs
4) New pesticides
5) New disinfection-by-products
b. Treatment-removal and absorption capability for all categories of
emerging contaminants
2. Factors to consider
a. The intent of this criterion is to address the potential for future
regulated constituents and plan ahead in a cost effective and
proactive manner
b. Animal activity
c. Non-point sources
d. Wastewater discharges
Corrosion- Health and consumer confidence issue. Apqressive water
that will leach harmful metals from pipes into the water (lead and copper
1. A higher ranking will be given to those alternatives that create the
lowest potential for aggressive water. The alternatives will be ranked
by:
a. Source water
1) Alkalinity
2) pH
3) Sulfate
b. Treatment
1) Corrosion control
2) Match Betasso treated water
Factors to consider
iaaszz.zio A2-4 osnaio~
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Appendix 2- Decision Model Criteria and Alternative Scoring
a. The intent of this criterion is to provide finished water that is not
considered aggressive
b. A pH below 7.8 is more corrosive
c. Alkalinity around 48 mg/L is less corrosive
d. High alkalinity above 100 mg/L increases copper corrosion potential
e. Low alkalinity increases both lead and copper corrosion potential
f. See attached source water quality table
III. Source Water
A. Water Rights Yield
1. Yield of the City's water rights portfolio is maximized over time by fully
using direct flow water when available and strategic use of available
reservoir storage water. Evaluation of alternatives should consider:
a. Ability to manage stored reservoir water throughout the year
b. Ability to manage stored reservoir water during droughts
c. Access to raw water sources available for direct use
d. Potential for increasing water rights yield through enhanced water
management or capacity of facilities
B. Consistency of quality and quantity 24/7
1. A higher ranking will be given to those alternatives that provide the
best potential for consistent finished water quality. The alternatives will
be ranked by:
2. Source water
a. Operational ease of delivering raw water at a consistent flowrate
a. Operational ease of delivering raw water of a consistent quality
b. Ability to blend raw water sources to improve quality
2. Treatment
a. Reliability: Consistent treatment operation year-round with less
process failure.
b. Efficiency: Minimize chemical usage and operations staff efforts.
3. Facts to consider
a. High quality treated water is more easily attained when raw water
sources feeding the treatment plant are uniform in both quality
characteristics and in flow rate of delivery. The intent of this
criterion is to assess the impact on water treatment from
inconsistent source water quality, including reliability and e~ciency
and the need for additional treatment process barriers.
C. Portfolio Flexibility (Flexibility in use of raw water supplies)
1. System reliability improves with flexibility in selection of raw water
sources in response to changes in treated water demands or amount
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Appendix 2- Decision Model Criteria and Alternative Scoring
of raw water available from a source. Evaluation of alternatives should
consider:
a. Number of options available for means of delivering raw water
b. Ease of changing water sources in response to changing conditions
c. Seasonal limitations of use on raw water sources
D. Availability of Raw Water Delivery Facilities
1. Management of raw water sources is made more difficult by facilities
that are unavailable for raw water delivery. Evaluation of alternatives
should consider:
a. Reliability of facilities
b. Capacity limitations
c. Restrictions on facilities use due to external factors affecting
operations or water quality
IV.Water Treatment i Operations Criteria
A. Worker safety
1. Alternatives will be ranked highest based on least amount of staff
interaction or exposure required. The altematives will be ranked by:
a. Chemicals
1) Type (degree of hazard)
2) Amount required
b. Processes
1) Type (complexity, hazard)
2) Number (how many processes required)
c. Infrastructure maintenance
1) Cleaning grateslstrainers at intakes
2) High power
3) Mechanical complexity
d. Factors to consider
1) The intent of this criterion is to evaluate the potential risk to staff
based on type and amount of chemical required and type and
number of processes required.
B. Process Flexibility
1. Alternatives will receive highest ranking based on the most flexibility in
processes (number and type) required. The alternatives will be ranked
by:
a. Maximizing the maturity and robustness of the technology
b. Maximizing the fabrication and engineering design of the various
facilities, unit processes and components.
2. Factors to consider
iaaezz.zio A.2-6 osnaio~
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Appendix 2- Decision Model Criteria and Alternative Scoring
a. The purpose of this criterion is to compare the need for treatment
processes. The more robust and flexible a process is the broader
the range of treatment concerns addressed will.
b. As source water variability and vulnerability increases the number
and/or complexity of processes will increase.
c. Treatment - add table of data to support
1) Oxidation - manganese, turbidity
2) Caustic and/or acid - pH fluctuations
3) Coagulant - turbidity fluctuations
C. Reliability/Redundancy
1. A higher ranking will be given to those alternatives that provide the
best potential for consistent finished water quality. The alternatives will
be ranked by:
a. Source water
1) Operational ease of delivering raw water at a consistent flow
rate
2) Operational ease of delivering raw water of a consistent quality
3) Ability to blend raw water sources to improve quality
b. Treatment
1) Reliability: Consistent treatment operation year-round with less
process failure.
2) Efficiency: Minimize chemical usage and operations staff
efforts.
3) Minimize need to adjust treatment processes and/or chemical
dosage on regular basis.
c. Factors to consider
1) High quality treated water is more easily attained when raw
water sources feeding the treatment plant are uniform in both
quality characteristics and in flow rate of delivery. The intent of
this criterion is to assess the impact on water treatment from
inconsistent source water quality, including reliability and
efficiency and the need for additional treatment process
barriers.
D. Maintenance
1. A higher ranking will be given to alternatives that:
a. Minimize the complexity of facilities, unit processes and
components
b. Maximize the expected life of facilities, unit processes and
components
c. Maximize the maturity of the technology, fabrication and
engineering design of the various facilities, unit processes and
components
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~ Appendix 2- Decision Model Criteria and Alternafive Scoring
E. Monitoring/Remote Operation
1. A higher ranking will be given to those alternatives that exhibit lower
complexity and higher reliability.
a.
2. Facts to consider
a. The intent of this criterion is to compare the complexity and
reliability of the monitoring requirements of each alternative. It
does not include the monetary cost of monitoring since this will be
part of the monetary evaluation.
F. Staffing
1. A higher ranking will be given to those alternatives that minimize the
requirements based on these parameters: include:
a. Total number of staff
b. Expertise of staff
c. Supervision
2. Facts to consider
a. The intent of this criterion is to compare the staffing requirements of
each alternative. It does not include the monetary cost of staffing
since this will be part of the monetary evaluation.
G. Residuals disposal
1. Alternatives will be ranked by least volume and best quality of
residuals.
a. Source water
b. Treatment
2. Factors to consider
a. Locations for residuals disposal are becoming increasingly difficult
to find so it is important to minimize the production of residuals.
(Recent analyses indicate current residuals may contain low levels
of radioactivity making it even more difficult to dispose of.)
V. Risk
A. Unexpected Acute Contamination
1. A higher ranking will be assigned to those alternatives that best
minimize potential public health impacts from such risk. The
aiternatives will be evaluated by
a. Potential for slug-loading of a large amount of harmful
contaminant(s) with potential for treatment breakthrough
144922210 A.2-8 06/18/07
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Appendix 2- Decision Model Criteria and Alternative Scoring
.
b. Potential for slug-loading of contaminant(s) with the capability for
disabling or disrupting water service on a temporary or long-term
basis
2. Facts to consider
a. Initial specific risk/contaminanUtreatability criteria and assessments
for water supplies addressed in this study have been developed as
a part of the 2003 Water Utility Vulnerability Study. Further
development of detailed source/treatment risk assessment
information for these supply/treatment system, as well as for the
entire city of Boulder treatmenUsource portfolio, is currently being
planned by the city's utility security work group( with the goal of
incorporating the findings into this and other related long-term utility
planning efforts).
B. Unexpected Chronic Contamination
1. A higher ranking will be assigned to those alternatives that best
minimize potential public health impacts from such risk. Alternatives
will be evaluated by
a. Potential for contamination from bodily contact with the source (wild
or domestic animal and/or human)
b. Potential for contamination from other recreational activities
adjacent to supply
c. Potential for contamination from outfalls emptying into supplies
2. Facts to consider
a. The intent of this criterion is to address day-to-day risks due to
existing non-point-sources in water supplies. Focus is on
contaminants that are difficult to remove or inactivate through
treatment and on events that could cause a moderate to significant
waterborne disease.
b. Initial specific risk/contaminant/treatability criteria and assessments
for water supplies addressed in this study have been developed as
a part of the 2003 Water Utility Vulnerability Study. Further
development of detailed source/treatment risk assessment
information for these supply/treatment system, as well as for the
entire city of Boulder treatment/source portfolio, is currently being
planned by the city's utility security work group( with the goal of
incorporating the findings into this and other related long-term utility
planning efforts).
C. Adaptability to Unexpected Future Changes -
1. Future changes in source water quality. A higher ranking will be
assigned to those alternatives that best minimize risk of public health
impacts from potential future increases in source WQ risks.
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Appendix 2- Decision Model Criteria and Alternative Scoring
a. The intent of this criterion is to address the tendency toward
increased risk over time from contaminant sources noted in (A.2.)
as a function of:
1) Local or regional policy(s) regarding activities allowed or
encouraged in or near drinking water supplies.
2. Facts to consider
a. Increased level of impacting activities over time in popular water
suppfy corridors.
b. Increased source contamination risks/loading will increase
background public health risks as well as increase the likelihood of
peaking events/ waterborne disease outbreak(s). Specific risk
information to support this criterion to be developed in risk
assessment efforts noted above.
3. Future changes in regulatory standards. A higher ranking will be
assigned to those alternatives that best minimize risk of non-
compliance with future drinking water standards.
4. Facts to consider
a. The intent of this criterion is to address the risk of drinking water
quality standards (especially those pertaining to source water risks)
becoming significantly more stringent in the future.
b. Potential inability for city to meet future standards to the extent that
CIP and other planning does not anticipate regulatory dynamics/
upcoming challenges. (See discussion on significant limitations of
current standards which contributes to likelihood of increased future
stringency).
D. Infrastructure Vulnerabitity
1. A higher ranking will be assigned to those alternatives that best
minimize risk of damage to infrastructure that would impede
purveyance or treatment of the potable water supply. The alternatives
will be evaluated by
a. Potential for impacts from natural events (i.e. weather-related
events)
b. Potential for impacts from accidental or intentiona{ events
2. Facts to consider
a. The intent of this criterion is to address risks to facilities in sources
and treatment which would impede delivery of drinking water to the
city's distribution system.
b. Why it is a problem: Interferes with reliable delivery of water for
drinking and other potable uses and for fire protection.
E. Power interruptions
3. A higher ranking will be assigned to those aiternatives that best
minimize risk of power interruptions with potential to impede
~aas2z zio A.2-10 osnaro~
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Appendix 2- Decision Modei Criteria and A/ternative Scoring
purveyance or treatment of the potable water supply. The alternatives
will be evaluated by
a. Potential for power interruptions affecting the treatment plant
processes
b. Potential for power interruptions affecting the transmission of water
to the distribution system
4. Facts to consider
a. Power interruptions can result in serious consequences for both
water supply and quality. To the extent that an interruption
interteres with water treatment plant processes, tap water quality is
at risk (including regulatory compliance capability). Water
transmission may also be compromised by a power outage to the
extent that pumping/ system telemetry are impacted.
F. Chemical Delivery/Usage
5. A higher ranking will be assigned to those alternatives that best
minimize risk from potential chemical delivery interruptions which
would impede treatment and public health protection capability. The
alternatives will be evaluated by
a. Potential for treatment chemical interruption (i.e. distance of source
from plant, mode of transportation, frequency of deliver)
6. Facts to consider
a. The intent of this criterion is to address risks to WQ/public health
from interruption of availability/ delivery of chemicals required to
treat water for potable use.
b. Lack of such chemicals in sufficient quantity could preclude the
city's ability to treat water to quality or quantity levels needed.
VI.Environmental and Public Acceptance
A. Adjacent land use Compatibility
1. Chemical hazards (us on neighbors)
2. Recreational use (neighbors on us
3. Development
4. Road crossings
B. System-Wide Water Uniformity
1. The desirability of providing equal water quality to all customers
a. Quote from Ridge Dorsey re: Industry need to pretreat water "We
could go through our list of permitted industries an give you a count
from that select group, but that would not be representative of the
entire city. Many industry types such metal plating, electronics
~aaszz.zio A.2-11 osnaio~
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< Appendix 2- Decision Modei Criteria and Alternative Scoring
assembly, food/beverage manufacturing, pharmaceutical, R&D
labs, even auto washing prefer to use de-ionized water, and
sometimes ultra pure (reverse osmosis) water. Potable water for
these commercial applications would likely need to be treated to
specific industry standards in any location. I'm not aware of any
industry that did not locate to Boulder due to water quality."
C. Construction Impacts
1. A higher ranking will be given to those alternatives that exhibit these
characteristics:
a. Minimizing the impacted land area and associated restoration
requirements
b. Minimizing underground excavation and associated materials
handling
c. Minimizing the number of subcontractors and suppliers
2. Facts to consider
a. The intent of this criterion is to compare the construction impacts of
each alternative. It does not include the monetary cost of
construction since this will be part of the monetary evaluation.
D. Consumer Confidence
3. A higher ranking will be given to those alternatives that provide the
highest consumer confidence.
a. Source
1) Finished watertaste, odor, temperature and appearance.
2) Manganese
3) Hardness.
4) Effects on local business
b. Treatment
1) match Betasso Treated water
c. Facts to consider
1) The intent of this criterion is to evaluate public perception and
acceptance of treated water.
E. Permitting
F. Energy Requirements
3. The intent of this criterion is to compare the energy requirements and
the secondary affects of these requirements. It does not include the
monetary value of the energy requirements since this will be part of the
monetary evaluation. The alternatives will be rated based on
minimizing the quantity of the following:
a. Capacity/load rating (MVA)
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~ Appendix 2- Decision Model Criteria and Alternative Scoring
b. Net energy consumption (use minus production) (Mw-hr)
c. Equivalent amount of coal (tons)
d. Equivalent amount of S02 (tons)
e. Equivalent amount of NOx (tons)
f. Equivalent amount of C02 (tons)
VII. Other Criteria
A. Public Acceptance
The intent of this criterion is to compare the anticipated public acceptance
of each alternative. It does not include the monetary cost of any project
mitigation designed for public acceptance since this will be part of the
monetary evaluation. A higher ranking will be given to those alternatives
that exhibit these characteristics:
a. Minimizing the visual impacts of based on the need for above grade
buildings and facilities
b. Minimizing acquisition of land, easements and right-of-way
c. Promoting economic sustainability within the city's service area
iaaszzz~o A.2-13 osnaio~
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Appendix 2- Decision Model Criteria and Alternative Scoring
Alternative Scoring Worksheets
~aaszz.zio A.2-14 osnaio~
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Appendix 2- Decision Model Criteria and Alternative Scoring
Crvoto Giardia Vvuses
Alternative Treatment
Strate Score Comments: Additional log removal
tA qOz 2 0.02 0.67 0.96
7B CIOZ+UV 10 4.02 4.67 1.46
1C CIOz+GAC+UV 10 4A2 4.67 1.46
2A CIOz 2 0.02 0.67 0 96
2B CIOz + UV 10 4.02 4.67 1.46
2C CIOz+AOP 3 0.54 13.16 27.60
3 CLP+CIOi 6 1.52' 2.17' 2.46'
'Based on 1.501og reduction in E.coli by using GLP
WaterQuality: DBPs
AHemative Treatment
Strate Score Comments: CIOi> O„ GAC varies, UV -- no effect
1A q0z 9
1B CIOz+W g
1C CIOz + GAC + W 9 TOC removal varies with GAC life-cycle
2A CIOz 9
2B CIOz+UV 9
2C CIOz+AOP 10
3 CLP + CIOZ g Pipeline gives consistent water quality allovnng treatment optimization
UV -- no con~ribution to DBP reduction
CIOz - Effective oxidation ot NOM
AOP -- Effective oxidation of NOM
GAC - effective adsorption depending on GAC age
WaterQuali : Or anicMicro ollutants
Attemative Treatment
Strate Score Comments: AOP> GAC» UV = CIOi
1A CIOz 2 Minimal oxidation
1 B CIOz + UV 3 Minimal oxidalion and photolylic degradation
1C CIOz+GAC+UV 7 Adsorptionvanesv-nihcontaminantandGACage
2A CIOz 2 Minimal oxitlation
26 CIOz + UV 3 Minimal oxidation and photolytic degradation
2C CIOz+AOP 10 Reservoirdilulion+effectiveoxidation
3 CLP + CIOz 8 Source water protection + minimal oxidahon -- EDCs have very low concentreli
iaaszzzio A.2-15 osnaio~
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Appendix 2- Decision Model Criteria and Alternative Scoring
Water QualiH: Inorganic MicropolluWnts
Alternative Treatment
Strate Score Comments: Reduced As, U, Cr, Pb, Cd, Cu
tA CIOz 6 Oxidant+conventionaltreatment
1B CIOz+UV 6 Oxidant+cornentionalireatment
1C CIOz+GAC+UV 6 Oxidant+convenlionaltreatment
2A CIOZ 7 Oxidant+convenlionaltreatment
26 CIOz + UV 7 Oxidant + conventional treatment
2C CIOz +AOP 8 Ophmized oxidation + cornentional treatment
3 CLP + CIOz 10 Source water proteclion + reservoir dilulion + oxidant +convenhonal Vealment
Water~ualiri: Mannanese
Alternative S~ent Score Comments
1A CIOz 8 Sourcewateravoidance+effectiveoxidant
1 B CIOz + UV 8 Source water avoidance + effective oxidant
1 C CIOz + GAC + UV 8 Source water avoidance + effective oxidant
2A CIOi 7 VariableMn-effectiveoxidation
2B CIOz+UV 7 VariableMn--effectiveoxidation
2C CI02+AOP 8 VariableMn+Twostageoptimizedoxidation
3 CLP + CIOz 10 Source water protection + effective oxidation
Water Quality: Taste and Odor
Altemative Treatment
Stmte Score Comments
1A CIOz 5 ModeretelyeRectiveoxidant
1B CIOi+UV 5 ModeretelyeHectiveoxidant
1C CIOz + GAC + UV 7 Moderatelry effective oxidant, adsorption vanes with contaminant and GAC age
2A CIOx 5 Moderately effedive oxidant
26 CIOz + UV 5 Moderately effedive oxidant
2C CIOz+AOP 10 Optimizedoxidation
3 CLP + CIOz 8 Source water protection + moderately effective oxidant
iaaszz z~o A.2-16 osnaio~
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Appendix 2- Decision Mode! Criteria and Alternafive Scoring
Wafwr Oualitvt T~S and SuHate
Alternative Treatment
Strate Seore Comments
tA CIOz 3 Seasonal reservoir usage + no treatment
1B CIOi+UV 3 Seasonalreservoirusage+notrealment
1C q0z + GAC + UV 3 Seasonal reservoir usage + no treatment
2A CIOz 2 Yearvround reservoir use + no Ueatment
2B CIOz + UV 2 Year-round reservoir use + no treatment
2C CIOz + AOP 2 Year-round reservoir use + no treatment
3 CLP+qOz 10 Sourcewaterprotection
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Appendix 2- Decision Mode/ Criteria and Alfernative Scoring
Source Water: Consistency
Altemative Treatment
Strate S~o~e Comments
1A CIOz 2 Seasonal canal usage with low TDS & sulfate
1 B CIOz + UV 2 Seasonal canal usage vnth low TDS R sulfate
1C CIOz + GAC + UV 2 Seasonal canal usage with low TDS & sulfale
2A CIOz 5 Year-round reservoir use vnth higher TDS & sal5ate, seasonaf Mn occurance
26 CIOz + UV 5 Year-round reservoir use with higher TDS & sulfate, seasonal Mn occurance
2C CIOz + AOP 5 Year-round reservoir use with higher TDS & sulfale, seasonal Mn occurance
3 CLP + CIOz 10 Year-round CLP with low TDS & sulfate
Source Water: Water Rights Yield
Alternative Treatment
Strate Score Comments
1A CIOz 5 Seasonal reservoir usage
1 B CIOz + UV 5 Seasonal reservoir usage
1 C q0z + GAC + UV 5 Seasonal reservoir usage
2A CIOz 2 Year-round reservoir usage
2g CIOi+UV 2 Year-roundreservoirusage
2C CIOz+AOP 2 Year-roundreservoirusage
3 CLP+CIOz 10 Year-roundCLPusage
Source Water: PoMolio Flexibility
Alternative Treatment
Strate Score Comments: Time limit on reservoir storege (use it or lose it)
1A CIOi 5 Requires seasonal reservoir atorage
1 B CIOz + UV 5 Requires seasonal reservoir srorage
1 C CIOz + GAC + UV 5 Requires seasonal reservoir storage
2A CIOz 2 Requires year-round reservoir storage
2B q0z + W 2 Requires yearround reservoir storage
2C CIOz+AOP 2 Requiresyear-roundreservoirstorage
3 ClP t CIOz 1 D No reservoir storage reqwred
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Appendiz 2- Decision Model Criteria and Alte~native Scoring
Smnr.w Watae AvailahiliN
Alternative Treatment
Strata Seore Comments: Both BFC and BR uttimatey require canal use
tA CIOz 5 Requires seasonal reservoir storage
1 B CIOi + UV 5 Requires seasonal reservoir storage
1 C CIOz + GAC + UV 5 Requires seasonal reservoir storage
2A CIOi 4 Requires year-round reservoir storage
2B CIOz + UV 4 Requires year-round reservoir storage
2C CIOi + qOP 4 Requires year-round reservoir storage
3 CLP + CIOz 10 No limitation on availabiliry
iaaszz.z~o A.2-19 osneio~
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Appendix 2- Decision Model Criteria and Alternative Scoring
Water7reatmend0 eretions: WorkerSafe
Alternative Treatment
Strate Score Comments
1A CIOz 10 No additional energized equipment and maintenance
16 Ct02+ UV 7 Additional energized equipmentand maintenance
1 C CIOz + GAC + UV 6 Additional energized equipment, maintenance, and GAC replacement
2q CIOz 10 No additional energized equipment and maintenance
2B CIOz + UV 7 Additional energized equipment and maintenance
2C CIOz + AOP 6 AddRional energized equipment, maintenance, and chemical handling
3 CLP + CIOz 10 No additional energized equipment and maintenance
qOz 0
UV 3
GAC -1
AOP -4
CLP 0
WaterTreatmenUOperations: ProeessFlexibility
PJternative Treatment
Strata S~~ Comments
1A CI02 6 Adjustable oxidahon
1 B CIOz + UV 8 Adjustable oxidation and UV disinfection
1 C CIOz + GAC + UV 8 Adsorption varies with contaminant and GAC age, adjustable UV disinfecUOn
2A CIOz 6 Adjustable oxidation
2B CIOz + UV 8 Adjustable oxidation and UV disin(ection
2C q0z +AOP 10 Greatest Flexibiliry for TOC, DBPs, T&O, Mn
3 CLP + CIOz 6 Adjustable oxidation
Water TreatmenUOperations: Process Reliabili
Alternative Treatment
Strate Score Commen[s: Knowledge antl operational control of process(es)
1A CIOz 7 CIOz mature (chlorite), source water variabiliry
1 B CIOz + UV 6 CIOz mature (chlorite), UV adolescent, source water variabiliry
iC CIOz + GAC + UV 5 GAC adolesceM, UV adolescent, source water variability
2A CIOz 8 CIOi mature (chlorite), source water variability
2g CIOz + UV 7 CIOz mature (chbrite), UV adolescent, source water variability
2C CIOz +AOP 7 CIOz mature (chlorite), AOP adolescent, source water variability
3 CLP + CIOz 10 Pipelme mature, CIOz maWre (chlorite)
Source water variability
BPC -3
BR -2
CLP 0
Technology
Mature 0
Adloescent -1
New -2
~aaszzz~o A.2-20 osnaio~
BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Appendix 2- Decision Model Criteria and Alternative Scoring
WatarTrealmantlOoarations: ProtessRedunda0tv Berri¢tS
Alternative Treatment
Strate Score Comments: Maximize barriers
1A CIOz 6 8~0 ~ri ,~„~ -0~
"
ie cioz+w s ~os x10
Score=
~Nb
-~~
iC CIOz+GAC+W 9 11.5 ..~+~
2A CIOZ 6 $ 0 ne,,,kp # barriers in altemative
28 CIOz + UV 8 10.5 No,,,u~ max # barriers in alternatives
2C CIOz+AOP 70 130
3 CLP+CIOz 70 13.0
WatwrTreatmentlOoeretions: Maintenance
____ --___
Alternative ____ _ . _
Treatment
Strate
Score
Comments: Deduets for each additional maintenance requirement
1q CIOs 10 No additional maintenance
1B CIOz + W 7 Additional maintenance for UV
1C CIOz + GAC + UV 4 Additional maintenance for GAC (3) and UV
2A CIOz 10 No additional maintenance
2B CIOz + UV 7 Additional maintenance and UV
2C CIOz + AOP 6 AddRional maintenance for AOP
3 CLP + CIOz 10 No addRional maintenance
CIOi 0
UV 3
GAC -3
AOP -0
CLP 0
Wa}arTreafmant/Onwre[ions Siaffina
Altemative Treatment
Strate Score Comments: Effort ExpeRise Supervision
1A CIOz 8 -1 0 -1
1B CIOZ+UV 7 -1 -1 -1
1C CIOz+GAC+UV 7 -1 -1 -7
2A CIOi 8 -1 0 -1
2B CIOz + UV 7 -1 -1 -1
2C CIOi+AOP 5 -1 -2 -2
3 CLP+CIOz ~0 0 0 0
Base score = 10 Treatabiliry
BFC Worsl -1 0 -1
BR Intermedial -1 0 -1
CLP Best 0 0 0
iaaszz.z~o A.2-21 osna~o~
_ BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
~ ~r Appendix 2- Decision Model Criteria and Alternative Scoring
WaterTreatmenUOperations: ResidualsDisposal Solids: ~uantiry ~ualiry Chemicals
Altemative Treatment
Strate Score Comments
1A CIOi 7 -1 -2 0
16 CIOz + UV 7 -1 -2 0
1C CIOz+GAC+UV 5 3 -2 0
2A CIOi 6 -1 3 0
26 CIOz + UV 6 -1 3 0
2C CIOz+AOP 5 -1 3 -1
3 CLP+CIOz ~0 0 0 0
Base score = 10
~aaszz.z~o A.2-22 osnaim
BRWTF INTECaRATED SOURCE WATER AND TREATMENT STUDY
Appendix 2- Decision Model Criteria and Alternafive Scoring
Rie4e Ar.ufa Contaminalion
Altemative Treatment
Strate Score Comments: Source water protection onty, no treatment
1q CIOz 3 Highlywlnerable,BFC
16 CIOi+UV 3 Hightyvulnerable,BFC
1C CIOz+GAC+UV 3 Highyvulnerable,BFC
2A CIOi 5 Moderately wlnerable, reservoir dilution
2B CIOz + UV 5 Moderatey wlnerable, reservoir dilution
2C CI02+AOP 5 Moderateywlnerable,reservoirdilution
3 CLP+CIOz 10 Minimallyvulnerable
Risk: Chronic Confamination PalhoGens Organics Inorganics
Alternative 7reatment
Strate Score Comments: Micropollutants and emerging conWminants
1A CIOz 2 3 3 -2
18 CIOz+UV 5 0 3 -2
1C CIOz+GAC+UV 7 0 -1 -2
2A CIOz 5 -2 -2 -1
26 CIOZ+UV 7 0 -2 -1
2C CIOz+AOP 9 0 0 -1
3 CLP+CIOz ~0 0 0 0
Prevention takes precentlence over treatment
Base score = 10 BFC -3 -3 3
BR -2 -2 -2
ClP -1 -1 -1
CIOz 0 0 *1
UV +3 0 0
GAC 0 +2 0
AOP +2 +3 +1
CLP +3 +2 +2
Risk: AdapWbili to Future R ulatory Environment Path ens Or anics Inorganics
Alternative Treatment
Strate Score Comments
1A CIOz 2 0 0 +1
1B CIOz+UV 5 +3 0 +1
iC CIOi+GAC+UV 7 +3 +2 +7
2A CIOz 2 0 0 +1
2B CIOz + UV 5 +3 0 +1
2C CIOz+AOP 8 +2 +3 +2
3 CLP+CIOz ~0 +4 +2 +3
Base score = 1 CIOz 0 0 +1
UV +3 0 0
GAC 0 +p 0
AOP +2 +3 +1
CLP +3 +2 +2
~aaszz zio A.2-23 osnaioi
~ BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
~ Appendix 2- Decision Model Criteria and Alternative Scoring
Risk; Infrestructure VulnerobiliN
Altemative Treatment
Strete Score Comments: Source water infrast~ucture contamination only
1A CIOz 4 Highlywlnerable
1B CIOi+UV 4 Highlyvulnerable
1C CIOz+ GAC + W 4 Highly vulnerable
ZA CIOz 5 Moderately wlnerable, reservoir difficult to decontaminate
2B CIOz+UV 5 Moderatelywlnerable,reservoirdiffculttodecontaminate
2C CIOi + AOP 5 Moderately wlnerable, reservoir difficult to decontammate
3 CLP+CIOz 10 Minimallyvulnereble
Both BFC and BR ultimately rely on canal to deliver water Risk V. High -4
Source Probability Severity Score High -3
BFC High High 4 Mod -2
BR Low V. High 5 Low -1
CLP V. Low V. Low 10 V. Low -0
Risk: Consumable Delive IUsage
Alternative Treatment
Stmte Score Comments
1A CIOz 10 No Addihonal risk
1B CIOz+UV 8
1C CIOz+GAC+W 5
2A CIOZ 10 No Additional risk
2B CIOz+UV 8
2C CIOi+AOP 4
3 CLP+qOz 10 NoAdditionalnsk
Chemical Risk
q0z -2
UV -2
GAC 3
03 3
H~Oz -3
iaaszz zio A.2-24 osnaio~
BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Appendix 2- Decision Model Criteria and A/ternative Scoring
Environmental and Public Acce tance: Ad'acent Land Use Com atibili
Altemative Treatment
Strat Seore Comments
1A CIOz 4 Development, road crossings, recreation
1 B CIOz + UV 4 Development, road crossings, recreation
1C CIOz+GAC+UV 4 Development,roadcrossings,recreation
2A CIOz 4 Development, road crossings, recreation
2B CIOi + UV 4 Development, road crossings, recreation
2C CIOZ+AOP 3 Development, road crossings, recrealion, LOX delivery
3 CLP+CIOs 70 Noincompatibilities
Base score =
LOX delivery
Development
Road crossings
Recreational use
Envirenmental and Pu61fe Acceotance: Svstem Wide Finished Water Uniformib
-_____.__
Alternative .. .
7reatment
Strote
Score
Comments: Primarily TDS and Sulfate
1A CIOz 3 Higher morganic content dunng reservoir use
1 B CIOZ + UV 3 Higher inorganic content during reservoir use
1C CIOz + GAC + UV 3 Higher inorganic content during reservoir use
2A CIOz 2 Continuousy higher inorganic content
Zg CIOz + UV 2 Continuousy higher inorganic content
2C CIOz+AOP 2 Continuouslyhighermorganiccontent
3 CLP + CIOz 10 Source water most closey matches Betasso source
Environmental and Public Accentance: Construction
Altemative Treatment
Strete Score Comments
1A CIOz 10 CIOz
1B CIOz+UV 7 CIOZ+UV
iC CIOz+GAC+UV 4 GAC+UV
2A CIOz 10 CIOz
28 CIOz+UV 7 CIOz+UV
2C CIOz+AOP 6 CIOZ+AOP
3 CLP+CIOz 4 CLP+CIO¢
CIOz
UV
GAC
AOP
CLP
iaasz2.z~o A.2-25 osne~oi
BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Appendix 2- Decision Model Criferia and Alternative Scoring
Environmantal and Puhlic AcceoGnce: Permiltina/Reaulatorv Acceotance
Alternative Treatment
Strete Score Comments
1A CIOz 10 CIOz
iB CIOi+UV 8 CIOZ+UV
1C CIOz+GAG+W 6 GAC+UV
2A CIOz 10 CIOz
28 CIOz + ~V 8 qOi + W
2C CIOz+AOP 8 CIOz+qOP
3 CLP+CIOz 6 CLP+q02
CIOZ 0
UV 2
GAC 2
AOP 2
CLP 4
EnvironmenWlandPublicAcceptance: Consumerconfidence
Pathoaens DBPs Oraanics Inoraanics Manaanese TRO TDS/SOd
Alternative Treatment
Strete Store Comments: Avoidanee takes precedence over treatment
1A CIOz 6 0 +1 0 +1 +2 +2 0
1B CIOz+UV 7 +1 +~ 0 +1 +2 +2 0
1C CIOz+GAC+UV 10 +2 +2 +1 +1 +y +3 0
2A CIO¢ 7 +1 +~ +~ +2 +1 +1 0
2B CIOz + UV 8 +2 +~ +1 +2 +1 +1 p
2C CIOz+AOP 9 +1 +1 +2 +2 +1 +2 0
3 CLP + CIOz 10 +1 +~ +1 +2 +2 +p +1
Base score = 0
Avoidance
8FC
BR
CLP
Treatment
CIOz
UV
GAC
AOP
CLP
0 0 0 0 +7 +1 0
+1 0 +~ +1 0 0 0
+~ 0 +1 +1 +1 +1 +t
0 +1 0 +1 +1 +1 0
+1 0 0 0 0 0 0
0 +1 +1 0 0 +1 0
0 0 +7 0 0 +1 0
0 0 0 0 0 0 +1
iaaszz zio A.2-26 osnsio~
BRWTF INTEGRATED SOURCE WATER AND TREATMENT STUDY
Appendix 2- Decision Model Criteria and Alternative Scoring
Environmental and Public Acceptance: Energy Requirements
Alternative Treatment
Strate Score Comments: Based on relative additional energy usage
1A CIOz 5 $22,750 5
1B CIOz+UV 3 $28,663 3
1C CIOz+GAC+UV 3 $28,663 3
2A CIOi 2 $32,500 2
2B CIOz + UV 1 $38,413 1
2C CIOz+AOP 2 $32,500 2
3 CLP+CI02 ~p $0 10
iaaszz zio A.2-27 osnaio~
~ ~-r-FJ~~Fr~~~NT ~
City of Boulder
Department of Public Works
Peer Review Comments for the Draft Report on Boulder Reservoir
Water Treatment Plant prepazed by Black & Veatch in 2007
May 31, 2007
Susumu Kawamura, Ph.D. P.E.
Purpose and Background
This memorandum provides a Peer Review of the draft report entifled " City of Botilder
Reservoir Water Treatment Plant Multi-Barrier Approach Study" in eazly 2007 for the
City by Black and Veatch (B&~. The purpose of the study completed by B&V is to
explore how to improve the treated water quality of one of the City's primary drinking
water sources, not only to meet upcoming, more stringent drinIdng water quality
standards, but also satisfy Yhe special treated water quality goals set by the CiTy including
the requirement for a mulri-barrier treatment process.
The Boulder Reservoir Water Txeatment Plant is rated a 16mgd capacity. The original
source of water for the plant is Carter Lake, which generally has good water quality but.is
diatant from the plant. Carter Lake water is transferred to the plant via the 21-mile long
Boulder Feeder Canal.
The raw water quality can change dramatically from the origin (Carter Lake) to the plant.
The actual raw water source for the plant is either pumped &om the Bottlder Reservoic,
which is located about a quarter mile from the plant, or directly from the Boulder Feeder
Canal which terminates about one mile from the plant.
The raw water quality supplying the plant is not as good as the original source water from
Carter Lake for two primary reasons:
1. There are numerous points of inflow and potential contamination/degradation of
the raw water along the 21 miles of uncovered Boulder Feeder Canal, and
2. The reservoir is used for recreational purposes as well as for drinking water
supply. It is also subject to stagnation and seasonal turuover of reservoir water. In
addition, the reservou water has higher total dissolved solids (TDS), including
sulfate, sodium hazdness and manganese, compazed with the original source of
water.
Even with these water quality challenges, the treatment plant is currendy producing good
quality water which meets Federal and State drivking water regulations, in part due to the
good performance of dissolved air flotation (DAF) clarification process, as long as the
coagulant dosage is optimized. As a side note, I recommended the DAF process over 10
yeazs ago when the plant was being evaluated.
? ,
Timeline:
On Apri14~', 2007, Utilities Project.Manager, Annie Nobie, asked me to provide an
independent Peer review of the draft report.
SubsequentIy, my proposal dazed April 5~ was approved by the City.
On Apri112, 2007, I received chaptexs 1 through 8 of the drafted report prepared by B&V
from ihe City. I also received follow-up information (the minutes of the April lb, 20Q7
Water Resources Advisory Board) on Apri119. The City requested that I return my
review comments by the ead of April.
None of the information that I received from the City contained any previous study
reports or any detailed design criteria of existing processes ofthe plaut. Nor did it
include proposed altemative processes. Also, no hydraulic profiles of the entire system
were included.
Therefore, it was difficult for me to make an accurate evaluation of each proposed
altexnarive.
I submitted my first review memorand~ to the City on Apri126, 2007.
However, it was not accepted due to my misunderstanding of certain conditions as well
as some grammatical problems with the documents.
On May 15, 2007, I received a letter from Robert Hazberg, Utilities Planning and Project
Management Coordinator, wLich pinvided a few undeilying circumstances and issues
related to the Boulder Reservoir WTP. Also, additional information including the latest,
simplified water tr~eatment altematives presented to the Water Resources Board (WRAB)
was received for my evaluation.
I was given specific instructions that my review should be focused on the proposed
ireatment altematives and their associated costs and scoring/ranking based on the selected
criteria.
The City requested a submission date for mq new memorandum of 7une 1, 2007.
Eaecutive Snmmary
There are two basic rules for all indushies in the business of manufacturing products and
goods_
The fust rule is to select and secure the best available raw material for making the best
products using simple and reliable process. The second rule is, if the best raw materials
aze not available, then the production process should be simple, reliable and effective. It
should consist of proven processes that are operator friendly as well as cost effective.
The water supply business is no exception.
The recommendation for the City of Boulder BRVJTF Muhi-Barrier Appxoach Study by
B&V and further evaluarion of the B&V report by the engineering staffs of the City both
came to the same conclusion. The prefeaed alternative is to obtain the highest quality
water possible and minimize the risk of fiuther contaminaflon of the water supply, using
a new pipeline from Carter Lake to the existing plant.
Tlus conclusion agrees with the Basic Rule Number One as ouUine above-use the best
c;uality source available.
Now, let us look into a few details of the opinions.
Evaluation and discussion of the BBcV report is based on the lvstorical raw water quality
data and performance of eacisting treatment plant. The quality of the treated water was
examined not only based on the regulatory standazds, but also the special quality goals
developed by the City.
The unique situation for the City is the difference in treated water quality between the
Boulder Plant and the other water treatment plant (Betasso) due to mineral quality
differences.
As a result of the different water quality from the two sources, the mixing zone within the
distdbution system varies frequently due to changing flow conditions.
Consequently, the City Water Deparhnent often receives complaints from customers due
to these water quality differences. This is a political pmblem rather than the health .
problem, since the complaints are focused on mineral quality, wlrich meets health
standsrds, but is different enough to be noticed by customers.
Therefore, in my opinion, the City has set unreasonably low sulfate and TDS goal for the
finished water produced by Boulder VJTP in order to satisfy the customers wlvch
received the varying quality.
Recently, both goals l~ave been relaxed somewhat by the City. But, 20 mg/L for sulfate
and 100 mg/L for TDS are still quite low laiowing that the EPA's Secondary Standard
(not health related) for these parameters aze 250 mg/L and 500 mg/L respectively.
These goals have resulted in the recommendation to build a long and costly raw water
supply pipeline from Carter Lake as presented in Altemative 3 of B&V report. The only
other way to meet these strict water quality goals while continuing to use the existing
Boulder VJTP sources would be to install a cosdy demineralization process.
Review of Altematives:
Table 6-1 entifled "BRVJTP Performance Criteria Weights and Water Delivery
Alternarive Scores" provides a summary of the evaluation.
It is my opinion Alternative 2 which is "BFCBR w/C102 and UV" is unreasonably
under-rated. One of the main reasons for the low ranking is due to poor virus inactivation
by UV disinfection as indicated in Table 5-2, 6-1 and other related tables. This is a
correct interpretation of the inability of UV to inactivate viruses. However, viruses aze
easily inactivated by free chlorine downstream of LTV. According to the C.T tables
provided by USEPA, 4-Log inactivation of virus at 0.5 C water temperatttre at pH 6-9 is
only 12. Thus, under 1 mg/L of free chlorine residual requires only a CT value of 12
mg/L- min.
Thus, a good virus inactivation can be achieved with 1 m~/I, of free chlorine residual for
only 12 minutes of contact time. I presume the e~cisting clearwell provides more than 12
minutes of contact time, especially with low water demands in the winter season.
The use of chlorine dioaude as the pre-oacidation should also result in significant vin, c
inactivation.
This condition was neglected by the B&V, report as well as by the City.
Additionally when the optimum coagulant feed rate to existing DAF process is
maint~ined, the DBP precursors in the raw water can be sufficiently removed so that the ~
level of DBPs in the distribution system should meet the cmxent required level.
Additional insurance for complete control of the DBPs would be to feed ammonia to the
finished water after CT requuements have been met. F3owever, since the finished water
from the Bettasso WTP is not chlorinated with chloramines, ttris approach requires
additional considerations.
In conclusion, Alternative 2 as defined by the most- recent simplified process schematic
appeass to be the prime candidate to provide a reliable and cost effective approach for
only about $3.0 million of capital cost in comparison to over $21 millions for the new
pipeline scheme. This is the recommended nhase one of the plant modification scheme to
meet ctttrent regulation. Incidentally, this scheme agrees with the Basic Rule Number
Two as outlined earlier.
The new pipeline scheme may be considered as the second nhase, if needed.
I would like to point out that the B&V's study report covered a wide range of critical
issues very well. However, it did not touch on the effects of anticipating a few problems
in the 21st century due to the defuute global warming trend, worldwide rapid population
growth and potential terrorist attacks.
Worldwide weather changes, including in the United States, haue already taken place.
Potential changes in rainfalls in many azeas including the tributaries of Catter Lake,
should be a concern. Current e~zeme drought conditions in the Southeast xegions of the
Unites States, which have historicaUy receive lots of rain, is probably caused by the
regional changes of the weather pattems. For example Lake Okeechobee in Florida has
almost dried up due to lack of rainfall and inflow_
Increasing population means a need for more water while increasing poIIution of water
sources at the same time. Terrorist attacks aze not an "if', but a"when.". It appears that
the proposed new pipeline between Carter Lake and the treatment plant could be
practically defenseless against terrorist acts of contamination and other actions.
Sudden deteriora6on of source waters can also be a real threat due to dischazge of toxic
substances by traffic accidents neaz the sources or by sudden lazge algae blooms.
For example I have experienced a situation recently where MIB/Geosmin levels were as
high as 500 ng/L for the source of water to the New Mohawk Water Treatment Plant (100
4
mgd) in Tulsa, Oklahoma in 2002. When I reviewed the last 60 years of raw water
quality data of the existed plant (before the design of new plant), the lughest TON was
only 3.0. Thus, a feed rate of 25 mg/L of powdered acrivated cazbon (PAC) feed system
was designed for the new plant. 71ris dosing rate vvould control up to about 30 to 50 ng/L
of Geosmin and MIB.
Incidentally, customers start noticing a bad odor from the tap water at concentrations as
low as 10 nglL. Since the maximum of 500 nglL and the duration above 50 ng/L of
Geosmin/IvIIB level lasted over three months after startup of the new water treatment
plant in Tulsa, both the Ciry's water department and myself had very hard time.
Many customers were questioning the decision to build an expensive new plant when it
could not adequately address the taste and odor problem.
The same situation occurred in 2001 for the Alto da Boa Vista Water Treatment Plant
(400 mgd) in Sao Paulo, Brazil. The MIB level of Guuapiranga Reservoir peaked as high
as 750 ng/L and the problem persisted for six monihs. The maximum level of these tsste
and odor causing substances in the past was about 50 ng/L.
Global wartning and many other circumstances certainly can create unexpected sudden
changes of raw water quality compazed to Yristoz3cal data.
This is another reason to caxefully re-consider the expense of constructing a new water
pipeline from Carter Lake and adding only a new chlorine dioxide process to existing the
treatment plant.
Miscellaneous Comments on the Black & Veatch Report
1) Chapter 2, Division C: Source Water Quality
* The water quality of the sources even Boulder Reservoir is actually not so
bad compazed with sources of other regions of the country, such as
Southwest, Midwest and South.
• A few times in the past the quality of ihe water exceeded the CiTy's goals
But, most of the times were under the goal. I think this raw water is
treatable with proper treahnent processes with a justifiable cost (except for
sulfate and TDS).
2} Chapter 2, Division D: BRVJTF Operational Data
" I agree with the descriptions by the B&V.
3) Chapter 3, BRVJTF Delivery Alternafive Contaminant Barriers
• Overall discussions in this chapter aze very good.
• The pollution along the Boulder Feeder Canal is surely the concem.
Aowever, it may be possibte to control the critical polluting azeas by either
covering the canal or replacing it with pipes at a rather reasonable cost.
No discussions aze provided on this subject.
• The problems of Boulder Reservoir aze discussed e3ctensively in the report.
But, one ofthe potential soluCions of various water quality problems is
mixing the entire body of water body using air bubbles from compressed
air or strong water j ets near the lake bottom level. Perhaps this discussion
was not included because the reservoir is open to active recreational uses.
4) Chapter 4: Multi-barrier Approach decision criteria
* Good discussions. No comments.
5) Chapter 5: Altemative Developmeut
• The alternatives 1 to 2C wexe Lejected because these altematives do not
meet the water quality goats of the City. The need for the goals is
understandable, but they ate unreasonably strict in my opinion
• The altemative 3 which is a new pipeline scheme is a good option. But, it
has certain minor risks as described in the Execuiive Summary of my
evaluation.
~ Chapter 6 : Performance Evaluation
First of all, I don't understand why construction cost is not in the Criteria Column
of Table 6-1. There is a term as"Conshuction" third from the bottom on the Cable.
But, the weight is only 1 and priority is only 0.006. Lf this is the construetion cost
RankingJWeighting, it seems to be too low.
As I mentioned eazliez in the Executive Summary Altemative 1B and 2B aze
not properly evaluated.
I would rank the altematives in the following order:
1. Altemative 3
2. AternativevlC and 2C
3. Altemative 2B
4. Alternative 1B
5. Alternative lA
6. Altemative 2A
7) Chapter 7: Economic Evaluation
• Figure 7-1 shows the estimated capital cost for the seven as well as the six
alternatives
It is difficult to check the figiixes because no drawings and adequate
design criteria aze available even ihough I did talk to B&V's engineer
briefly.
• However, since the checking ofthose esdmated costs was specifically
requested by the City, I spent some time to figiue them out based on my
own data and experience.
. My estimated cost of each alternative is as follows:
* Altemative 1B ( C102, conv. treat., i1V) : 2.16M ,($2.44M on Figure7-1)
Tlris is also Alternative 2 by simplified Alternative
(
* Altemative 1C (C102, conv. treat., GAC,UV) : 19.57M ($21.92M on Fig.7-1)
This is also Altemative 3 by the simplified Alternative
* Alternative 2C (C102, conv. treat., AOP) : 12.45M ($13.57M on Fig 7-1)
This is also Alternative 5 by the simplified Alternarive
* Alternative 3 is the new pipeline. This is also Alternarive 6 by simplified
Altemative: The City Engineers agreed with the B&V estimation of $21.06M
* The simplified Altemative No.4., C102, conv.treat, MF(CTF :$13.2M (~13221~
Overall my estimated cost and the cost shown on the B&V report are not much different.
8) Chapter 8: Prefeaed Alternative
• In general, I concw with the discussions in this chapter.
But, my preference is try the Alternative 2B and 2C as the phase one
project.
• It does not have a lazge capital cost and the work can be done within a
rather short time. After evaluation of the performance of tlus modification
work, the next modification - most likely the new pipeline between the
Cazter Lake and the treatment plant can be implemented.
Simplified Alternatives (Siz Alternatives) presented to the Water Resonrces
Advisory Board in May 2007
1) SimplifiedAlternatives
This is much clearer beriveen the altemative process and makes sense.
I like this form.
2) MF/UF akernative was added as Altemative No.4.
The membrane filter system operarion is computer controlled so thax the
number of plant operators can be reduced. But, backwashing every 10
minutes or so with so many control valves indicates that good mechanical and
system con~ol specialists are needed. Also, the membrane filters cannot
control taste and odor and precursors for DBPs which will still require
additional treatment processes.
Also periodic replacement of fouled membranes would be expensive.
3) Scoring of the six alternatives
I agree with the scores of the new Table 6-1 except Altemative Number 2
which you sent me recently.
MF/[TF altemative is no better than No.S ranking as shown on the table.
Note: See the item six on page 6 for my scoring of the six altematives.
4) Hydroelectric power generation using Carter Lake to the treaiment plant
Pipeline proposed
The energy shoztage will continue to grow in the future, and the cost of eleetric
power will go up steadily from now on.
Therefore, it is my opinion thet if the new pipeline betrveen the Carter Lake and
the treatment plant is built, the 200 psi water pressuce difference should be used
to generate power.
End
~-~~C Ef r11~~rL
BLACK & VEATGH
~ bnilAi~aWOf~dsf~8~ronee+•
ENENGY . WATEN ~ INFOflMATION . 00VERNMENT
City of Boulder, CO
BRWTF Multi-barrier Approach Study
Peer Review Responses
B&V Project #144922
B&V File A-1.3
Ms. Annie Noble
Utilities Project Manager
City of Boulder
1739 Broadway
Boulder, CO 80306
June 7, 2007
Dear Annie,
Thank you for providing Black & Veatch the opportunity to review and respond to
the peer review comments of Dr. Susumu Kawamura regarding our draft report entitled
"City of Boulder BRWTF Multi-BarrierApproach Study", dated March 21, 2007 and with
revisions dated April 19, 2007. We appreciate Dr. Kawamura's opinions of our work on
your behalf, for as an industry leader with more than 50 years of experience in drinking
water treatment he is eminently qualified to evaluate our draft report. Based on a
thorough review of detailed peer review comments provided, we find that Dr. Kawamura
generally concurs with the analyses and findings of our report. We offer responses to
selected peer review comments, as described in the following pages.
Sincerely,
~,1,.~.,~,~~-w ~J ,~1Fm~',
/
Christopher J. Tadanier, PhD
BLACK & VEATGH
, ~wimina+worldoraiHore~e^~
ENEPGY • WATEfl . INFOXMATION . QOVEFNMENT
City of Boulder, CO
BRWTF Multi-barrier Approach Study
Peer Review Responses
B&V Project #144922
B&V File A-1.3
Black & Veatch Responses to Selected Peer Review Comments
1. (pg. 2, last paragraph) We concur with Dr. Kawamura's basic business rules as
applied to drinking water treatment which are paraphrased as: 1) treat the best
available water source, and 2) use treatment processes that are simple, reliable,
effective, operator friendly, and cost effective. These rules have been the paradigm
of drinking water treatment in the United States for more than a century, and formed
the basis of our approach to the analyses and findings provided in our draft report.
2. (pg. 3, paragraphs 2 through 5; pg. 6, second sentence) Black & Veatch does not
concur with Dr. Kawamura's opinion that the drinking water staff within the City
Utilities Department (City) has set unreasonably low water quality goals for total
dissolved solids (TDS) and sulfate in finished drinking water. It is our view that the
City's objective in setting TDS and sulfate goals below the Secondary Standards
promulgated by the United States Environmental Protection Agency (USEPA) is to
provide fairness and equity in finished drinking water provided to all its customers,
and not to exclude any particular BRWTF treatment alternative from consideration.
3. (pg. 3, paragraph 5; pg. 6, first sentence) As noted by Dr. Kawamura, the only
BRWTF multi-barrier approach alternative evaluated that satisfies the City's TDS
and sulfate goals is A{ternative 6, that includes full pipeline containment of raw water
from Carter Lake to BRWTF. We concur with Dr. Kawamura's statement that
"These goals are partly responsible ... in the recommendation to build a long and
cosUy raw water supply pipeline from Carter Lake ..." However, decision criteria
related to TDS and sulfate concentrations in finished water played only a minor role
in the overall ranking of alternatives, as evidenced by the cumulative weight of only
0.05 (or 5% of the total decision weight). To illustrate the small impact of TDS and
sulfate related considerations in alternative ranking, the non-economic performance
of alternatives was re-evaluated with the TDS and Sulfate and System-Wide
Uniformity criteria each given 0 weight. As shown in Table PR-1 below, the relative
performance of aiternatives changed only very slightly when TDS and sulfate related
issues were omitted from consideration.
1
~ BLACK & VEATCH
bsild[np a yy0~~ of diMare~e++
ENEP6V . WATER • INPoBMATI6N • GOVEHNMENT
City of Boulder, CO
BRWTF Multi-barrier Approach Study
Peer Review Responses
B&V Project #144922
B&V File A-1.3
Table PR-1
Alternative Rankings With and Without TDS and Sulfate Related Criteria
Decision Model Alt. 1 Alt. 2 Alt. 3 Alt. 4 Alt 5 Alt. 6
With TDS and Sulfate criteria 0.512 0.573 0.606 0.554 0.603 0.942
Without TDS and Sulfate criteria 0.523 0.588 0.622 0.568 0.619 0.939
Abbreviations:
BFC/BR - Boulder Feeder Canal or Boulder Reservoir Source, CIOZ - chiorine dioxide, UV - ultraviolet
light, GAC - granular activated carbon, MF/UF - micro-/ultra-filtration, AOP - advanced oxidation
process including ozone, CLP - Carter Lake pipeline source
Alt. 1: BFC/BR with CI02 preoxidation
Alt. 2: BFC/BR with CIOZ preoxidation and UV disinfection
Alt. 3: BFC/BR with CI02 preoxidation, GAC adsorption, and UV disinfection
Alt. 4: BFC/BR with CIOZ preoxidation and MF/UF
Alt. 5 BFC/BR with CIOZ preoxidation and AOP
Alt. 6: CLP with CIOZ preoxidation
~'~TDS and Sulfate, System-Wide Uniformity criteria removed from consideration.
Thus, considerations other than the City's TDS and sulfate goals for finished water
quality were largely responsible for the substantially higher ranking of the Carter
Lake pipeline alternative (Alt. 6).
4. (pg. 3, last paragraph) We do not concur with Dr. Kawamura's opinion that
Alternative 2(Boulder Feeder Canal/Boulder Reservoir source with chlorine dioxide
pre-oxidation and UV disinfection) was unreasonably under-rated because
insufficient Ct credit was assigned for virus inactivation by free-chlorine. In fact, as
shown in Table 5-2 of the B&V draft report each alternative evaluated was assigned
temperature and flow dependent Ct credit well in excess of regulatory requirements
or City water quality goals. Furthermore, as indicated in Table 6-1 Alternative 2 was
~ BLACK & VEATCH
nn~ia~~. worid.r a~x~m~~~
ENEP6Y + WATER • INfONMAT1010 . GOYERNMENT
City of Boulder, CO
BRWTF Multi-barrier Approach Study
Peer Review Responses
B&V Project #144922
B&V File A-1.3
assigned the highest possible score of 10 with respect to the Pathogens criteria.
Thus, assigned Ct credit for virus inactivation by free-chlorine played no part in the
relatively lower performance score of Alternative 2 compared to Alternative 6.
Rather, the cumulative effects of the pertormance of Alternative 2 against all other
criteria were responsible for its lower perFormance score.
5. (pg. 4, second paragraph) Because of concerns related to nitrification during
distribution, sensitive sub-populations, and the growing body of evidence related to
adverse health effects of disinfection byproducts (DBPs) such as NDMA, the City is
not contemplating use of chloramine (combined-chlorine) for residual disinfection.
Therefore, the current B&V study focused on DBP precursor removal and NOM pre-
oxidation as strategies for DBP control.
6. (pg. 4, fourth paragraph) Dr. Kawamura raises the issue of global warming and its
potential impacts on weather patterns that could impact Carter Lake as the ultimate
water source for BRWTF. Although a detailed consideration of the potential impacts
of long-term global warming on the sustainability of the Colorado-Big Thompson
Project (CBT), of which Carter Lake is the terminal reservoir feeding BRWTF, is
beyond the scope of the current B&V study, we have reviewed additional water
quality, hydrologic, and geographic data not included in our draft report of March 19,
2007 to evaluate the potential for degradation of Carter Lake source water quality.
Based on our evaluation of this data, B&V believes that Carter Lake, as part of the
larger CBT Project, will likely remain a sustainable water source for BRWTF for the
foreseeable future.
There will undoubtedly be seasonal and annual changes in Carter Lake water
quality in response to climactic conditions. However, 35 years of historical data for
Carter Lake, during which time there have been several notable regional droughts,
do not indicate any long-term degradation in the overall water quality from this
source. Important water quality parameters including pH, alkalinity, and
hypolimnetic oxygen concentration have not shown any deteriorating trends with
time. The minimum recorded hypolimnion oxygen concentration in Carter Lake is
Q BLACK & VEATCH
y bU1~01R0YwQ~'!(IBf~IH8~B11CB°
ENEPGY + WATER • INFOBMATIOX • GOVEHPIMENT
City of Boulder, CO
BRWTF Multi-barrier Approach Study
Peer Review Responses
B&V Project #144922
B&V File A-1.3
approximately 3 mg/L, indicating that fully anoxic conditions associated with taste
and odor and soluble iron or manganese issues do not occur in Carter Lake. Total
dissolved solids (TDS) and dissolved sulfate have shown a slight decreasing trend
based on historical data, indicating improving water quality.
Perhaps the best indicator of the overall water quality of a lake is its trophic
status, which reflects the biological productivity in the water body. Biological
productivity in a water body is frequently classified based on potential for algal
growth, which if excessive may lead to rapid seasonal changes in water quality.
Lakes and reservoirs are classified as oligotrophic, mesotrophic, eutrophic, or
hypereutrophic based increasing potential for excessive algal growth or seasonal
algal "blooms". A number of trophic status indices (TSI) have been proposed based
on a single or multiple water quality parameters as measures of algal biomass,
including Secchi depth (water clarity), total phosphorus level, and chlorophyll a.
Historical trends for Secchi depth, total phosphorus, and chlorophyll a in Carter
Lake have not shown any tendency toward lower water quality. Of these
parameters, chlorophyll a is the most direct indication of algal biomass. Carter Lake
would be classified as oligotrophic based on chlorophyll a content, with a low
potential for water quality degradation due to algal blooms.
Carter Lake has a well protected watershed with minimal potential for future
water quality degradation due to point or non-point contaminant sources. Two dams
form Carter Lake in a natural depression in topography, resulting in a very small
watershed. The lake is surrounded by steep forested terrain and has no natural
tributaries. Much of the surrounding land resides in protected forests, parks, and
recreational areas. Lands bordering Carter Lake are also not suitable for large scale
agricultural concerns, and natural topography is not amenable to large scale
industrial operations. Carter Lake has a capacity of 112,230 ac-ft providing a large
dilution volume for any contaminant introduced directly or from surface runoff. Long-
term water quality degradation due to concentration of point or non-point
~ BLACK & VEATCH
buiidinD a WO~~d ef diflarance+•
ENEflGV . WATER • IIiFOWMATION . GOVEqNMENT
City of Boulder, CO
BRWTF Multi-barrier Approach Study
Peer Review Responses
B&V Project #144922
B&V File A-1.3
contaminant inputs is mitigated by seasonal water use, with greater than 50 °fo
annual turnover in the lake being typical.
The Colorado-Big Thompson (CBT) Project supplies water to Carter Lake
through a series of reservoirs, lakes, tunnels, and conduits. As such, the water
quality in Carter Lake is to a large extent dependent on water quality in upstream
waterbodies including Flatiron Reservoir (760 ac-ft), Pinewood Reservoir (2181 ac-
ft), Lake Estes (3,068 ac-ft), Mary's Lake (927 ac-ft), Grand Lake/Shadow Mountain
Reservoir (17,354 ac-ft), and ultimately Lake Granby (539,800 ac-ft). Flatiron and
Pinewood Reservoirs have similar topographic features as Carter Lake and are
located in undeveloped areas. Lake Estes has natural inflow from the Big
Thompson River water shed in Rocky Mountain Nationa{ Park and CBT flow from
Mary's Lake. Mary's Lake has no measurable natural inflow and receives CBT
water from Grand Lake via the Alva B. Adams Tunnel. Grand Lake is surrounded by
Rocky Mountain National Park on three sides and Shadow Mountain Reservoir on
the fourth. CBT water collected on the West Slope is pumped to Grand Lake
through Shadow Mountain Reservoir.
Because of the native topography and protected status of much of the land
surrounding the CBT Lakes and Reservoirs that ultimately supply Carter Lake, B&V
believes that municipal, agricultural, or industrial development on the scale
necessary to substantially degrade water quality in the CBT watershed is not likely
during the 30 year planning horizon of our study. Aithough development will
undoubtedly continue in selected locations adjacent to CBT facilities, most notably
Estes Park and Grand Lake, natural topography will tend to limit this growth and any
potential adverse impact it might have on CBT water quafity.
The operational practices used by The Northern Colorado Water Conservancy
District to manage the water supply in the CBT system also tend to mitigate any
impacts of seasonal water quality fluctuations in upstream reservoirs and Lakes on
water quality degradation in Carter Lake. The vast majority of CBT water transferred
to Carter Lake in any water year occurs during the winter and eariy spring, when
~ BLACK & VEATCH
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ENEHGY + WATEB • INfOpMATIOX • 604EflNMENT
City of Boulder, CO
BRWTF Multi-barrier Approach Study
Peer Review Responses
B&V Project #144922
B&V File A-1.3
water quality is not affected by any potential for temperature stratification, algal
blooms, or hypolimnetic oxygen depletion in the upstream lakes and reservoirs.
Furthermore, the large storage volumes and detention times of the CBT supply
system to Carter Lake provide the opportunity for substantial natural attenuation of
micropollutants that could potentially enter from intentional or unintentional sources.
7. (pg. 4, fourth paragraph last line) Dr. Kawamura states "It appears that the
proposed new pipeline between Carter Lake and the treatment plant could be
practically defenseless against terrorist acts of contamination and other actions."
Black & Veatch strongly disagrees with this statement. In our view, raw water
conveyance from Carter Lake to BRWTF in a buried pipeline offers minimal if any
opportunity for intentional introduction of contaminants, especially when compared to
the 21 miles of totally unsecured access to the Boulder Feeder Canal. Furthermore,
we believe that the majority of pipeline related infrastructure, namely the buried pipe,
would be relatively secure from terrorist activities. Appropriate and reasonable
security measures would secure access to localized structures such as the pipeline
headworks at Carter Lake and pressure reducing valve vaults or hydroelectric
facilities along the pipeline. This is in stark contrast to the Boulder Feeder Canal,
which could be easily breached or filled at virtually any location.
8. (pg. 4, fifth paragraph) We agree with Dr. Kawamura that "Sudden deterioration of
source waters can also be a real threat due to discharge of toxic substances by
traffic accidents near the sources or by sudden large algae blooms." As described in
Chapter 1 of the B&V project report, we believe that by far the most vulnerable
BRWTF source to unintentional point or non-point contamination is the Boulder
Feeder Canal. Contaminants introduced during conveyance in BFC are diluted in
Boulder Reservoir, somewhat mitigating their potential threat. As described in
response 6 above, we believe that the protected nature and large volume of the CBT
Project (Carter Lake as the terminal reservoir for BRWTF) makes this BRWTF water
source by far the least vulnerable to unintentional point and non-point contamination.
BLACK & VEATCH
~ hnilAiagslN(lf~dofdiHerancs*~
ENEpGY . WATER . ~NFOflMAT10N . 6PVEIFNMENT
City of Boulder, CO B&V Project #144922
BRWTF Multi-barrier Approach Study B&V File A-1.3
Peer Review Responses
As described in response 6 above, review of 35 years of historical water quality
data for Carter Lake indicate that its potential for seasonal blooms is low. Oxygen
depletion and hypolimnetic anoxia that typically follows a substantial algal bloom has
not been recorded during the past 35 years. In contrast, hypolimnetic anoxia and
associated manganese refease from sediment is an annua{ occurrence in Boulder
Reservoir during late summer and early fall. Measured chlorophyll a in Boulder
Reservoir is also typically twice that of Carter Lake, indicating enhanced algal
growth. Therefore, we believe that the Carter Lake source conveyed to BRWTF
through a dedicated pipeline has by far the lowest potential for sudden water quality
deterioration.
9. (pg. 6, item 6) and pg. 7 item 3)) We note that Dr. Kawamura has ranked the 6
BRWTF multi-barrier water delivery alternatives in essentially the same order as that
given in the Black & Veatch project report. Dr. Kawamura did feel that the numerical
performance score assigned to Alternative 2{Boulder Feeder Ganal/Boulder
Reservoir source with chlorine dioxide pre-oxidation and UV disinfection) by B&V
was lower than he would assign. Please see response 4 above for scoring of
Alternative 2.
10. (pg. 6, item 7) We note that Dr. Kawamura's capital cost estimates for the 6 BRWTF
multi-barrier water delivery alternatives generally agree with those presented in the
Black & Veatch project report to within 8% to 11 %, and to within 1% for Alternative
4. These percentage differences are weli within the level of accuracy expected for
Class-4 conceptual planning cost estimates as defined by the American Association
of Cost Engineering (+50 % to -30 %).
7
/ ? - ? ~ "~ ~ !'- - ~" ~ ~'~ ? ~~ ; ~ ~ ~ ~
Questions and Answers
Integrated Evaluation of Boulder Reservoir Water Treatment Plant
Source Water Protection and Treatment Improvements
June2007
1. What are the other priorities for spending $30 million in the Boulder water system
that would meet the overall goals of the utility better than the CLP, or is the CLP
the tap priority for capital spending at this time?
Staff Response:
From the perspective of Utilities Division staff, the Cater Lake Pipeline is a top priority for
capital spending at this time. This water supply source is considered much more vulnerable
from a water quality perspective than either of the city's other two sources of supply. The
project is also considered a top priority because of the opportunity for the city to collaborate
with other water providers and take advantage of a pipeline right-of-way that has already
been secured by the Northern Colorado Water Conservancy District. The pipeline is
considered an important long term investment in the city's water supply infrastructure that
will secure water quality from the vagaries of future development, uses and degradation of
Boulder Reservoir and the Boulder Feeder Canal corridor. In addition, the pipeline will
assist the City in meeting its security objectives for drinking water. As identified in the city's
Vulnerability Assessment, which was required by EPA, the Boulder Feeder Canal was
identified as the most vulnerable asset in the city's drinking water system.
Even so, the Carter Lake Pipeline project is considered desirable (see attached Criteria for
Categorizing Services, Attachment 1), but not essential per the city's business plan criteria.
Other important projects proposed in the 2008-2013 Water Utility Capital Improvement
Program (CIP) that are considered essential include:
1. On-going waterline replacement
2. Lakewood Pipeline repair/replacement
3. Barker Water System repair
4. Boulder Reservoir WTP improvements
5. Betasso WTP improvements
Further detail regarding these projects is presented in the CIP overview memo.
2. Is it the opinion of the City of Boulder staff and consultants that if the Carter Lake
Pipeline were constructed that there will not be any substantial change in Carter
Lake water quality that will lead to a need for additional water treatment plant
improvements beyond those recommended in conjunction with the Carter Lake
pipeline? In other words, is it the staff position that with the construction of the
Carter Lake Pipeline it will not be necessary to make future improvements in the
Boulder Reservoir WTP?
Staff Response:
See Responses to Questions 1 and 3 dated April 9, 2007 in the April 16, 2007 WRAB packet.
Page 1
3. A chart provided to WRAB indicates that TOC removal at the Boulder Reservoir
WTP has been decreasing over the past few years. This does n~ot appear to be
related to any changes in water quality in the Boulder Feeder Canal. What is the
plan to address this issue?
Staff Response:
The following graph shows regulated TOC removal data for January, 2003 through April,
2007. There seems to be a slight decrease in TOC removal in the later part of 2006 which is
probably due to testing various coagulants with the goal of reducing costs while maintaining
excellent water quality. Plant staff will continue to optimize chemical addition and
evaluation of additional treatment (i.e. Chlorine dioxide which is included in the next CIP
project for the BRWTP and or pH adjustment at the head of the planf). A University of
Colorado graduate student will conduct a pilot study over the next three or four months to
evaluate the effects Chlorine dioxide addition at the BRWTP on TOC removal and
disinfection byproduct formation among other things.
BRWTP TOC Removal vs Regulatory Ratio
Jan 2003 - Apr 2007
,- --
easin Canal ~ ~ Removal
~ Ratio
70 ~.._~. _ - _._
~ , ~ , _ 3,0
2003 - 2004 Settled Garrf~cauon ~ 20D5 - Current QssoNed Air Roatation qardication
Ferric sulfate antl Sumaclear 820B
::~•,,m ancl Surrodear 8208 in 2005 Various Coagulants in 2006
60 '. ____ ~
r ;~. - - - -- ......_ --- ---~ -
;
5u ' ~
.-. ._ . ..... ____ _..-___ ..__ ...___-___-. 3
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: 20
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Ratio must be abo~ 1A
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4. Pleasc providc a sprcadsheet with all flow and water quality f~rom the release from
Carter Lake to the Boulder Feeder Canal as it enters the BRVVTP or Boulder
Reservoir. What parameters are monitored and why'?
Staff Response:
Pa~e 2
The purpose of the Boulder Reservoir monitoring program is to monitor the reservoir and its
tributaries for condition, esthetics, nutrient loading and indications of possible pathogens and
other health related contaminants. Nutrients, metals, major ions, physical parameters, E. coli.
and chlorophyll a are monitored. Nutrients are monitored to determine tributary loading
rates and reservoir condition. Metals are monitored to characterize the BFC and make sure
there are no continual potential problems. Major ions are monitored to determine impacts to
operations and the customers. Physical parameters such as turbidity, dissolved oxygen and
pH are important to operations, source selection and may indicate contaminated water. E.
coli is used to determine contamination from human or animal waste and potential pathogen
risks to the water supply and treatment processes. Chlorophyll a is monitored as part of the
Boulder Reservoir condition assessment. (40 pages of electronic files can be provided upon
request).
5. Describe the actions that staff has undertaken to address concerns with the outfalls
to the Boulder Feeder Canal.
Staff Response:
On May 10, 2007 WQES staff inet with Northern Colorado Water Conservancy District
(Northern) staff, city Open Space/Mountain Parks staff and two land owners/land care takers
to discuss constructing outfall crossings over the BFC. A follow-up meeting was also
conducted on May 18`". The purpose of the meetings was to discuss with current and future
land owners, and current land care takers, diverting up-gradient drainage that currently runs
in to the BFC through defined outfalls over the BFC to down gradient land. These projects
would involve a drainage agreement with the land owners, the city funding design and
construction of the crossings and Northern designing and constructing the crossings. Public
Works Utilities has designated funding in 2007, and future years, to construct outfall
crossings (or other modifications) for high priority outfalls. In late 2007, it is anticipated that
construction of outfall crossings, or land grading to divert drainage in to existing crossings,
will be initiated for approximately 6 high priority outfalls. Additional outfalls will be
identified for modification in 2008. Attached (Attachment 2) is a summary of the May 10
and 18, 2007, meetings. The city is currently working with Northern to get a cost estimate
for the outfall rerouting work planned for the fall of 2007, as well as an estimate for
redirecting all of the outfalls.
6. Describe the actions that staff has undertaken ta address concerns with the
suspected source of pathogens to the Boulder Feeder Canal.
Staff Response:
As discussed in the response to question #5, the city is in the process of addressing high
priority outfalls which currently discharge to the BFC. As part of the process of identifying
high priority outfalls, WQES staff evaluated those outfalls which most frequently discharge
overland flow (from irrigation and/or storm events and snow melt) in to the BFC. High
priority outfalls were identified as those which most often flow, which seemed to coincided
with crop irrigation practices. Based on the various types of land uses draining to the outfalls
the types of contamination can be dependent on the drainage area land use. Typical land uses
include planted crops, livestock grazing or natural lands. Staff have also determined that
land uses practices can also change from year to year on the same property.
Page 3
7. Describe any studies undertaken by the city to reduce the water quality im~acts to
reservoir water quality from the marine shale underlying a portion of Boulder
Reser~~oir.
Staff Response:
No studies have been conducted by the city to evaluate this issue.
8. If it were not possible to construct the Carter Lake Pipeline what treatment process
woutd staff recommend for Boulder Reservoir WTP?
Staff Response:
Staff is recommending that chlorine dioxide, dissolved air flotation and backwash water
treatment be implemented in 2009 at the Boulder Reservoir WTP consistent with the
proposed 2008-2013 Captial Improvement Program (CIP.) These treatment processes are
assumed under all scenarios currently being evaluated as part of the Integrated Study project.
Staff is not recommending specific treatment processes beyond those proposed in 2009 at
this time. Treatment processes have been identified in the Integrated Study for comparison
purposes only. The treatment processes identified in this study are those that staff believes
would provide a similar level of water quality protection as the Carter Lake Pipeline.
Depending on the outcome of the decision regarding the Carter Lake Pipeline, staff will
continue to monitor water quality and treatment at the Boulder Reservoir WTP, as well as on-
~oing chan~es in our knowled~e of contaminant issues and associated regulations, in order to
assess the need for additional treatment in Che futln~c.
9. How many times in the history of the Boulder Reservoir WTP has the finished water
failed to meet SDWA primary standards?
Staff Response:
To date, no violations of Safe Drinking Water Act (SDWA) primary standards have occurred
at the f3oulder Reservoir WTP. This does not indicate that thcre is no or minimal risk of
primary standards violations as multiple communities around the United States experienced
multiple primary drinking water standards violations during a contamination event, when the
WTP had never experienced violations before. Most of these contamination events, such as
Milwaukee, were caused by high levels of contamination in the source water. Currently, in
WQES staff s apinion, SDWA regulations do not adequately address the risk of
contamination. In recent years, federal and state agencies have emphlsired the need to
develop and implement a Source Water Assessment Program (SWAP). The primary goal of
SWAP is to assist WTP's maintain compliance with SDWA regulations and protect public
health. This type of approach is generally considered a multi-barrier approach - a
combination of source water protection and treatment.
10. Have the specific outfalls or locations along the Bouldcr Feedcr Canal been
identi~ed that are the major contributors of crvpto/~iardia or other pollutants?
Page 4
Staff Response:
High priority outfalls have been identified by observation of flowing situations and by spatial
fecal/E coli monitoring.
The city has one Giardia and cypto data set from flowing outfall 655 collected May 30, 2006.
The results are as follows:
Total IFA (Immuno Fluorescence Assav) this means confirmed Giardia cvsts or
Cryptosporidium ooc~ts
Giardia <O.1/L
Crypto 10/L (4 of the 10 oocysts had internal structure present)
Comprehensive pathogen (specifically Giardia and Crypto) data have not been collected
along the BFC or outfalls other than outfall 655, but fecal coliform and E. coli have been
monitored, which are known pathogen indicators of human or animal waste. Two July 2002
city initiated studies which looked at fecal coliform along the canal show an increase in
colonies per 100 mis between Nelson and Oxford roads (see graphs below). The outfalls
scheduled to be eliminated this year are north of Prospect Road between Nelson and Oxford.
In addition to the 2002 studies, flowing outfalls have been monitored for E. coli in 2003,
2005 and 2006. This data is shown in the table below.
Page 5
Canal Fecal Coliform Spatial Data 7/15/02
140
120
J
0 100
0
~
~ 80
0
w
~0 60
U
~
~ 40
a~
~
20
0
2(So. 3(So. Of 4(Above 5(Above 6(Above 7(Flow 8(WTF
Rabbit Lyons) St. Vrain Nelson Oxford Rd.) gage Bldr. influent tap)
Mtn.) Rd.) Rd.) Rez.)
Location
Canal Fecal Spatial Coliform Data 7/18/02
120
J
~ 100
0
° 80
0 60
v 40
R
~
~ 20
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The table below shows E. coli counts from flowing outfalls during 2003, 2005 and
~nn~
Sam le ID Date Time Location Anal te Result Units
Z032451017 I 5/23/03 ~ 13:00 { BFC outfalls E coli 38.2 #/ 100mis
Z032451078 5/23/03 C 13:45 ; BFC outfalis E coli 435 #/ 100m1s
- ---- --
Z032131515 --- - -
5/29/03 I -- - -
14:46 t -
BFC outfalls -
E coli r--- -- -
228.2
~ -- -- --
#/ 100mis
- ------- - -
I
Z032131444
'
6 - --- - - ---
BFC outfalls --- - --
E coli -----
-
30.9
#/ 100m1s
- -
Z032131445 -- --
6/5/03 ~ ---
13:43
- - --- ------
-
BFC outfalls
-- - -----
E coli :
>2419.2 #/ 100m1s
Z032131446 i g
/5/03 1 14:25
~ BFC outfalls E coli 517.2 #/ 100m1s
Z03213144F '
~ 6/5/03 j 14:30 ~ BFC outfalls E coli 1203.3 #/ 100m1s
Z031771522
---- - 6/19/03
~ 14:37 i
- BFC outfalls
- -- E coli
- - 686.7
- #/ 100m1s
------- --
1
0
1
Z032131156 7/15/03 14:55 BFC outfal~s
--- E coli
- -- 151 _5 _
-- m
s
_# /
0
-
-- -----
Z051801053 -------
6/8/05 -- ---
11:15 ' - -
620 E coli 77.6 #/ 100m1s
Z051801058 6/8/05 ~ 11:20 } 609 E coli 499.5 #/ 100mis
Z051801100 6/8/05 I 12:00 i 359
-- - E coli
-- --- 128.1
- ------ #/ 100mis
--- --
-- ---
0 -- - ---
655 E coli 191.8 #/ 100m1s
-
829
Z052131 -----
7/13/05 t -
9:00 _
------ --
379 - - ----
E coli ~- - -- --
167.4 - ------ - -
#/ 100m1s
Z052101316 7/18/05 1 10:50 ~ 359 E coli 63.4 #/ 100mis
Z061381453 5/18/06 ~ 11:17 j 379 E coli 410.6 #/ 100m1s
Z061501310
~ 5/28/06 '
9:00 : ~
359
E coli ~ ~
365.4
#/ 100m1s
-- - - -----
Z061501249 - - - -
I 5/30/06 ~
9:45 ~ - -.... . .
655 -
E coli - - -- - •
142.1 - ------
#/ 100m1s
------ --
Z061531241
C 5/31/06 !
9:20 _
357
E coli -- -
547.5 - ------
#/ 100m1s
11. Has City Council approved the water goals established by Boulder utilities staff that
are more restrictive than the Safe Drinking Water Act requirements? If so, was
Council made aware of the potential cost implications of ineeting those goals?
Staff Response:
Utilities staff has developed internal finished drinking water quality operational goals for
multiple constituents, some of which aze more restrictive than SDWA MCLs. Internal City
goals are not required to be submitted to City Council since they aze not policy. Should City
Utilities staff find that meeting internal drinking water quality operational goals will
significantly impact capital costs or operational costs, Utilities staff will bring the operational
goals forwazd to City Council for review and comment.
12. What is the approximate annual cost (dollars and staff-hours) for monitoring the
Boulder Reservoir WTP raw water supply? What percent of the annual water
quality budget does this represent?
Staff Response:
The city's Source Water program budget is not separated out in the WQES Drinking Water
Program budget, therefore it is difficult to differentiate personal and equipment/material costs
for source water evaluation/protection efforts. Jim Shelley is responsible for the DWP
Source Water program but also has multiple other responsibilities as part of his position, so is
not solely dedicated to source water. Below is a list of typical activities for the Boulder
Reservoir source water program conducted by staff, and an estimate of the time required:
Page 7
• Source Water staff standazd monitoring (all year): 16 hours per month
• Laboratory Analyst for sample analysis (all year): 40 hours per month
• Supplies: $6, 000 per year
• Special monitoring (typically seasonal only):
o Boulder Reservoir critical period weekly monitoring (June - August): 10
hours per month
Misc. studies (June - August) - BFC E. coli monitoring; turbidity
monitoring; visual investigation: 16 hours field time per month; 16 hours
analytical time per month.
Estimated Annual Labor Hours: 270 hours Source Water staff; 528 hours Laboratory
Analytical staff.
$20,000
Estimated Annual Supplv Costs: $6,000
13. What will be the savings (dollars and reduction in staff hours) if the Carter Lake
pipeline is constructed and the Boulder Feeder Canal and Boulder Reservoir
supplies are only used in the event of a failure of the Carter Lake pipeline?
B&V Response:
The capital and annual operation and maintenance (O&M) costs for the 6 alternative multi-
barrier water delivery alternatives considered as part of the current Black & Veatch study aze
given in Figures 7-1 and 7-3 of the Black & Veatch report, and as provided to the board in
materials for the May 21, 2007 WRAB meeting. The present value of capital and O&M
costs, as well as the net present value of each alternative for the 30 yr planning period are
given in Figures 7-2, 7-4, and 7-5 of the Black & Veatch project report, and also provided in
materials for the May 21, 2007 WRAB meeting.
The City currently provides supervised operation of the BRWTF continuously, 24 hours a
day, 7 days a week, 365 days a year, and as a matter of policy plans to do so for the
foreseeable future. As such, Black & Veatch would not anticipate a significant change in
operational staff requirements for 9ny of the 6 BRWTF multi-barrier water delivery
alternatives evaluated as part of our current study.
14. What specific upgrades are needed at the Boulder Reservoir WTP to treat for the
pollutants from recreational activities at Boulder Reservoir?
B&V Response:
Review of historical finished water quality data for BRWTF indicates that there have been no
federal or state Primary Drinking Water Standards violations associated with drinking water
production at BRWTF. Based on review of historical source water quality data and the
current recreational uses of Boulder Reservoir, Black & Veatch believes that no additional
drinking water treatment processes are required to meet current or pending drinking water
standards. However, significant degradation of water quality in Boulder Reservoir in the
future could trigger the need for additional treatment at BRWTF.
Page 8
15. What are the annual chemical, energy and labor costs, respectively, to operate the
Betasso and BRWTP? What is the pumping cost per kgal for delivering water from
BRWTP to each of the pressure zones in the city's system?
Staff Response:
The 2006 annual chemical cost for Betasso was $347,492 and $154,476 for BRWTP. The
2006 annual energy cost for Betasso was $145,796 and $333,785 for BRWTP. T'he 2006
annual labor cost for Betasso was $1,219,734 and $767,671 for BRWTP. Betasso produced
4,900.11 Million Gallons of water in 2006 and the BRWTP produced 1,864.15 Million
Gallons.
The pumping cost per kgal for delivering water from BRWTP into zone two is done between
two pump stations. The Cherryvale pump station cost $0.024/ 1000 gallons. The Iris pump
station cost $0.024/ 1000 gallons. The 2006 energy cost at Cherryvale was $35,368 and Iris
was $30,814.
16. What are the projected cost savings (annual and per 1,000 gallons) for Boulder
Reservoir WTP treated water change if the Carter Lake pipeline is constructed
since this facility will have a higher quality supply and increased deliveries and Txed
costs will be distributed over a larger annual volume?
B&V Response:
Projected costs for BRWT'F multi-barrier alternatives evaluated as part of the curtent Black
& Veatch study aze as provided in our response to question 13 above. Discussions with City
staff indicate that the quantity of water treated at BRWTF is essentially independent of the
means by which raw water is conveyed to this location. Rather, treated water volume at
BRWTF is based on demand in azeas of the distribution system served primarily by BRWTF
and availability of treated water from the City's other WTP (Betasso).
17. How often has the Boulder Reservoir WTP withdrawn water from Boulder
Reservoir during the recreation season when the swim beach is operating? Has this
resulted in any violations of drinking water standards or measurable decrease in
tnished water quality?
Staff Response:
In recent years the Boulder Reservoir WTP has relied more on the Boulder Reservoir water
supply during the recreation season than in the past. Historically, raw water was typically
taken directly from the Boulder Feeder Canal during the recreation season to avoid water
quality concerns in the reservoir due to natural processes and recreational activities. Primary
factors for using Boulder Reservoir as a water supply more during the recreation season
include: increased recreational events occur along the Boulder Feeder Canal creating
contamination concerns; low canal flow which creates a higher potential for degraded water
quality due to less dilution; and, regular maintenance activities performed by the Northern
Colorado Water Conservancy District, including spraying of herbicides and algae control
using copper sulfate.
Page 9
Boulder Reservoir source water was used during the recreation season for two months in
2005 and two weeks in 2006. As faz as we know no drinking water quality violations have
resulted from recreational activities conducted at the reservoir.
18. What are the actual and modeled average and dry-year yields (annual numbers for
historic and synthetic hydrology) of the Carter, Barker and Silver Lake supplies
before any exchanges from Boulder Reservoir to the Barker or Silver Lake
supplies?
Staff Response:
The City's water exchanges were not previously assessed as part of the Carter Lake Pipeline •
evaluation because Boulder's use of exchanges is not affected by the presence or absence of
the proposed Carter Lake Pipeline. All options for use or non-use of the City's exchange
rights exist with or without the proposed Carter Lake Pipeline. A Carter Lake Pipeline sized
at 16 MGD would be sufficient to carry all water that is available for the BRWTP even if the
City did not exchange any water from its lower water system to its upper Boulder Creek
diversion points (see answer to Question 21 below). However, a new run of the Boulder
Creek Water Rights Model was completed to determine how much water might run through
the entire water system and through particulaz system components both with and without use
of exchanges. Historic diversion records were also reviewed back to the time when sufficient
detail was recorded to provide insight on the question. Data is presented in the tables at the
end of this response.
The City maintains reliable water supplies through drought periods by filling its upper
Boulder Creek reservoirs to the greatest extent possible during the high spring runoff period
in most yeazs. The City typically has a Four- to eight- week period each year during high
streamflow in the late spring to store the reservoir water supplies that will help carry the City
through the entire upcoming yeaz. The combination of the City's native basin water storage
rights and exchange rights assures that the City's reservoirs will fill by mid-June in almost
every yeaz with sufficient streamflow in the upper Boulder Creek watershed. Use of the
City's exchange water rights is necessary in some yeazs to fill the upper Boulder Creek
reservoirs when the native basin water storage rights are called out of priority. When
exchanging, the City trades water from Boulder Reservoir or Baseline Reservoir for
additional water at the City's upper Boulder Creek intakes.
The City can exchange water into storage in its upper reservoirs or can exchange for direct
flow into the raw water pipelines feeding Betasso WTP. Exchanges typically can occur
during an exchange season that is almost entirely limited to higher flow periods on the creek.
This is also when, in many years, the City's reservoirs are most likely to be filling under their
native basin water rights and the City's senior direct flow rights may be yielding enough to
fill the City's pipelines without use of exchange. Therefore, water exchanges are used only
when needed because the City's native basin water rights have been called out of priority.
The total annual amount of water exchanged for direct flow use during 285 modeled yeazs of
system operation ranged from 302 acre-feet to 2542 acre-feet and averaged 1854 acre-feet.
The total annual amount of water exchanged for reservoir storage during 285 modeled years
of system operation ranged from 108 acre-feet to 9463 acre-feet and averaged 2688 acre-feet.
The amount exchanged compared to the amount of City water supplied by native basin
rights, CBT, and Windy Gap is shown in the figure below.
Page 10
City of Boulder Modeled Exchange Amounts
Normal Operations under Buildout Conditions
35000
30000
25000
r, 20000
m
m
m
.
u
i6 15000
10000
5000
0
O"~ ~"~ 'L'3 ^~"~ A"~ ~"~ ro"~ '1"~ 0'~ ~"~ O"~ ^"~ ~."~ ^~'j b"~ h"~ 6"~ 1'S ~"~ ~"~ O"~ ^"~ 'y"~ '~"~ A"~ ~"~ ~o^' 1"~ ~"~
~.~ ~.~ ~~ ~~ ~.~ ~.~ 01 ~~ ~.~ ~~ ~.0 ~.~ ~.~ ~.~ ~.~ ~.~ ~.0 ~~ ~.~ ~.~ ~.°~ ~.°~ ~°~ ~.°~ ~°~ ~.°j ~.°~ ~°~ ~°~
year
~Total Deliveries ~Total Exchange to Direct and Storagel
Exchanges help to maintain the carry-over water levels in the City's Boulder Creek
reservoirs that protect against major water shortages during drought periods. Additional
water can be taken into storage during higher flow years for carrying forward into lower flow
years. Based on modeling of Boulder's water system over a 285 year period of operation
under build-out water demand conditions, the City would experience 12 years with reduced
water deliveries caused by drought if the exchange rights are used as planned. If the
exchange rights were not used in the future, there would be 75 years with reduced water
deliveries due to drought out of the 285 modeled years. The reliability criteria for the water
system that were adopted by City Council specify that water use restrictions due to drought
should not occur more often than 14 times in a 285 year period. Therefore, the City could
not meet the established water system reliability criteria without use of the exchange rights.
The increased number of years with shortages is illustrated by comparison of the following
fi~:ures.
Page 11
City of Boulder Modeled Total Water Deliveries
Normal Use of Exchange Rights under Buildout Conditions
35000
30000
25000
„ 20000
d
m
m
U
10 1500D
~oooo
sooo
^ Betasso WTP Total Output 063rd St WTP Total
City of Boulder Modeled Total Water Deliveries
No Use of Exchange Rights under Buildout Conditions
35000
30000
25000
„ 20000
m
d
d
`u
1° 15000
10000
5000
If senior water rights calls from lotver on Boulder Creek or from the South Platte occur
duriny,: the spring reservoir tilliny~ period, the City's reservoir storage rights will be called out.
Page 12
0
~,1p'y ^1~.,~ ~~,L^~ ~1,~.~ ^~a"~ ~1,'"y ~~6^~ ~1.`^~ ^~~^~ ~~~"~ 1~0"~ 10~'~ ~~,L'j ~~,~g ~~~"~ ^~~~y ~~6"~ ~$.`'S ~$~'y 1~~'S ~~9 19~'~ ~9ry^S ^~n~"~ ^9y,'~ ~~y'3 ~96"~ ~~1'3 ~9~'~
year
0
~.~~~ ~.~^~ ~1~~ ~+1~~ '~7A~ ~~~~ '~16~ '~1~~ '~1~~ '~19~ '~$~~ '~~1~ '~~~~ '~~~~ '~~~ ~~y~ ~$6~ '~~~~ '~$$~ '`~9~ '`'~~ '`~'^~ ~9~~ '`~'~~ '`~'A~ ~~'y~ '`96~ ~'~~~ ~`~'~~
year
^ Betasso WTP Total Output ^ 63rd St WTP Total Output
The exchange mechanism is used to continue storing in the reservoirs during the critical high
flow period when water is physically available at the high mountain reservoir diversion
points by satisfying other water rights with an alternative supply such as CBT. Only water
rights calls coming from a point below the discharge out of Boulder Reservoir can be
satisfied in this manner. Senior calls occurring above this point on the river must be
answered by allowing water to pass by the City's storage reservoirs. Efforts are made to store
as much water as possible during the high spring runoff because streamflows quickly drop to
typical summer levels that are too low to allow the City to store water in its reservoirs either
under its native basin rights or through exchange.
River conditions at any particular time create what is known as the "exchange potential."
The exchange potential on Boulder Creek varies from year to year and season to season
based on the call for water by other water right owners. The City's ability to exchange water
is limited by the lack of exchange potential on the river during most times of the year. For
example, the amount needed to satisfy senior ditch rights on Boulder Creek from just west of
Boulder to 75th Street is typically in the range of 170 cfs during the summer. Therefore, the
City can usually only exchange water for continued diversions into Barker Reservoir when
there is enough flow into and out of Barker Reservoir to maintain more than 170 cfs for the
downstream calls above 75`" Street. Sometimes there is enough water in the creek that water
can be exchanged for direct diversion into the City's upper pipelines as well as into storage.
However, under the City's agreements with the Colorado Water Conservation Board,
exchanges are also limited at all times that Boulder Creek flows below Orodell are less than
15 cfs.
Without use of the exchange rights, the City's upper reservoir storage space would be used
much less effectively and would occasionally be emptied as shown in the figure below.
During 285 years of modeled system operation, the lowest reservoir storage level reached
with use of exchanges was 3259 acre-feet. Without exchanges, the upper reservoirs were
emptied completely on seven occasions during the 285 year period.
In addition to the jeopardy to adequate water supplies that empty upper reservoirs would
cause for the entire city, the effects on the upper pressure zone (Zone 3) of the treated water
distribution network on the west side of Boulder would be even more challenging. If no
water is available for delivery into the upper side of the City's distribution system from
Betasso, then Zone 3 would need to be fed by pumping water up from BRWTP. Although
BRWTP is sized at 16 MGD to provide sufficient water to meet the essential indoor water
needs of the City under build-out conditions, this water has to travel through two other
pressure zones and a series of pumping stations to make it to Zone 3. Although upgrades to
the capacity of these pumping stations are planned in the future, they are not presently
capable of moving sufficient water supplies into Zone 3 to meet essential needs. In addition,
if the water users within Zones 1 and 2 do not cut back all water use to essential indoor need
levels, the water provided by BRWTP will be depleted before reaching Zone 3. Therefore,
the City's water system planning has included an emergency reserve reservoir supply of not
less than 3000 acre-feet in the upper Boulder Creek reservoirs to assure that water deliveries
can be made to Betasso WTP even under the most extreme conditions. This objective cannot
be met without use of the City's exchange rights.
Page 13
City of Boulder Modeled Water System Operations
Minimum Storage Level in Upper Boulder Creek Reservoirs
40000
35D00
30000
25000
w
m
d 2D000
u
A
15000
1D000
5000
Data regarding the City's ability to exchange water is presented below in Tables 1 and 2.
The amounts shown for modeled exchangeable water are not limited by the amount of CBT
or Windy Gap water available at Boulder Reservoir, but are limited by river exchange
potential. Exchange rights might not be used in any given year because of lack of exchange
potential or, conversely, so much water availability for native basin water rights that it is not
necessary to use the exchange rights. In interpreting the data, it is important to understand
that the water system components work synergistically to produce the total system yield.
Some parts of the system will be used more extensively than other parts in different years
depending on the hydrology of the particular year. Even though values for a specific yield
have been assigned to individual parts of the comprehensive system, adding together the
minimum or maximum yields of individual components will not lead to getting the minimum
or maximum yields of the entire water system since these values are unlikely to occur in the
same year for each component. Also, in actual practice, use of a particular system component
in any given year might be low for reasons other than lack of water availability such as due to
maintenance shutdowns for part of the year
Page 14
0
~,~~`~ .,~~.~ .,~~y~ ~,~~y~ ~,~P~ ~,~5~ ~.~0~ ^11~ .~0~ ~.~~~ .~~~ .~~.~ ^~ti~ ~~~y~ ~~b~ ~~h~ ~~~°~ ~~1~ ~~~~ ~~o'~ ^°j~~ ~°~~~ ^°ti~ ^°`~`S ^°,b^~ ^°,y`~ ~°f°^~ ~°,,~^~ ^°,~^~
year
~without exchanges ^with exchanges
Table 1:
Modeled Annual Diversions with Build-out Water Demand Based on Tree Ring Derived
Hydrology Dating from 1703 (values in acre-feet)
With normal use of Withaut exchanges
exchanges
System Component Avg Max Min Avg Max Min
Betasso WTP 16078 24203 9813 14103 17847 7583
TotalOut ut
Lakewood Pipeline 8~28 12489 5863 8705 12471 5258
Direct Flow
Barker Pipeline 2344 4984 1237 2310 4976 1245
Direct Flow
Storage Releases to '742 3650 100 1601 3681 180
Lakewood Pipeline
Storage Releases to 2407 8715 0 1484 5975 0
Barker Pipeliae
Lakewood Pipeline 179 493 0 0 0 0
Direct Exchange
Barker Pipeline 1675 2271 232 0 0 0
Direct Exc6ange
SL Watershed
Exchange to 435 3015 19 0 0 0
Storage
Barker Reservoir
Exchange to 2253 8430 72 0 0 0
Stora e
Total Amount 4542 10095 1279 0 0 0
Exchan ed
Boulder Reservoir 12411 13937 8513 13738 15185 9618
WTP Total Out ut
(Maximums and minimums are not additive to get system totals because they do not occur in the
same years for each system component.)
(The minimum amounts exchanged were 1279 acre-feet in 1714 and 1392 acre-feet in 1828 when
streamflows were respectively 216% and 140% of average streamflow.)
(The maximum amount exchanged was ] 0,095 acre-feet in 1849 which was a year with streamflow at
97% of average.)
Page I S
Table 2:
Historic Annual Diversions with Actual Water Demand (values in acre-feet)
Up~er Boulder Creek Facilities to Betasso WTP BRWTP
Calendar Direct Storage Exchange Exchange
Farmers CBT/
Year Flow Right to Direct to Direct ~'indy
Diversions Diversions Use Stora e Ga
1995 7707 10231 1036 0 0 5156
1996 6442 9268 2990 952 398 3095
1997 7923 11267 2242 0 310 3660
1998 7970 6249 1293 2716 644 4555
1999 8847 9372 2066 0 319 4437
2000 7560 1408 1867 7522 46 7334
2001 7824 8030 1297 1736 145 7419
2002 7154 433 1181 2677 0 6619
2003 9122 10547 1047 0 88 5171
2004 8992 14 882 6598 0 2992
2005 8561 4772 135 1744 130 4758
2006 7392 30 610 7096 137 5584
Average 7958 5968 1387 2586 185 5065
19. How will the City of Boulder use its Farmers Ditch water and the 2,000 AF of
storage in Boulder Reservoir available for storage of this water for delivery to the
Boulder Reservoir WTP between May 1 and July 31 if the Carter Lake pipeline is
constructed? How does this affect the firm yield of Boulder's water supply?
Staff Response:
The City's Farmers Ditch water will be used in the same manner as it is presently used. The
Farmers Ditch water included in the 1989 change decree is decreed for direct use only. It
cannot be stored in the 2000 AF of storage space reserved in Boulder Reservoir between May
1 and July 31 for receiving delivery of "City Water" under the 1975 Agreement between the
City and NCWCD. When Farmers Ditch water flows into Boulder Reservoir, it must be used
immediately and so is accounted for as having been taken directly through the Boulder
Reservoir Water Treatment Plant (BRWTP). If Boulder is not physically pulling water
directly from Boulder Reservoir into the BRWTP at a time when Farmers Ditch water is
flowing into the reservoir, then the Farmers Ditch water is exchanged against CBT water that
would otherwise be taken into the BRWTP from the Boulder Feeder Canal. The Farmers
Ditch water in Boulder Reservoir, as the exchanged-against water, becomes accounted for as
CBT water in Boulder Reservoir and is available for later use by CBT allottees. This same
mechanism will be used to exchange Farmers Ditch water for CBT water that would
otherwise be delivered into BRWTP from the Carter Lake Pipeline. The exchanged CBT
water would either remain in Carter Lake or bc dclivcred into Boulder Rcservoir as needed
by the CBT system.
Pa~e 16
20. What are the reductions in native streamflow in Middle Boulder and North Boulder
Creek as a result of the City's decreed and permitted exchanges from Boulder
Reservoir supplies to Barker and Silver Lake supplies?
Staff Response:
The City's Boulder Creek Model that is used for operational modeling of the water system
uses a quarter-monthly time-step. Therefore, it is not well-suited to determining
instantaneous streamflow levels associated with the City's diversions. Some information on
the reductions in streamflow related to the City use of exchanges can be gained from review
of historic diversion records and stream gage records. Exchanges and streamflow levels in
2006 were compared since the use of exchanges in 2006 is similar to other years when
exchange potential on the river exists. The following graphs show the difference in actual
2006 streamflows below Barker and Lakewood Reservoirs and streamflows if no exchanges
had occurred in 2006.
Effects of Exchange on Streamflow in April 2006
zs
zo
15
N
U
~Q
5
0
(no exchanges to Barker occurred in April 2006)
Page 17
1 2 3 4 5 6 7 8 9 1 D 11 12 7 3 14 7 5 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
Day of Month
^ actual flow at Lakewood ^flow at Lakewood w!o exchange
Effects of Exchange on Streamflow in May 2006
450
^ actual tlow at Lakewood L] flow at Lakewood w/o exchange
^ actual flow at Barker ^ flow at Barker wlo exchange
Effects of Exchange on Streamflow in June 2006
soo
soo
aoo
~ 300
200
100
^ actual flow at Lakewood O flow at Lakewood w!o exchange
^ actual flow at Barker ^ flow at Barker wlo exchange
Page 18
0
1 2 3 4 5 6 7 S 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
Day of Month
Effects of Exchange on Streamflow in July 2006
350
300
250
200
N
V
150
700
50
1 2 3 4 5 6 7 8 9 10 71 12 73 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
Day of Month
^ actual flow at Barker ~ flow at Barker w!o exchange
(no exchanges to the Silver Lake Watershed system occurred in July 2006)
The City's use of exchanges occurs mostly during high streamflow periods. Exchanges do
not usually occur during low flow periods in the late summer and winter due to limited water
physically available in the stream for diversion by the City and water demands by other water
users that cannot be satisfied with an exchanged supply. In addition, the City's agreements
with the Colorado Water Conservation Board state that exchanges will be curtailed when
streamflows below Orodell drop below 15 cfs. In reviewing the 2006 records, the City's use
of exchanges never reduced flows below Barker to less than 75 cfs and most often occurred
when Middle Boulder Creek was flowing at mare than 100 cfs. On North Boulder Creek,
there were only two days in 2006 during April when use of exchanges dropped creek flows
below 6 cfs. On one of these days, flow dropped to 3 cfs and on the other day was 5.1 cfs.
In both instances, streamflow levels remained above the minimum instream flow levels
defined by the Colorado Water Conservation Board.
The minimum streamflow levels that are presently provided and protected with the joint
City/Colorado Water Conservation Board instream flow program were developed based on
fisheries habitat studies using the IFIM and R2Cross methodologies. Additional studies
showed the optimum habitat in Middle Boulder Creek occurred between 20 and 50 cfs for all
life stages of fish in the stream. The optimum habitat levels do not correspond with
achievable natural habitat levels even in the absence of any human effects because the high
springtime flow levels reach hundreds of cfs. Absent some means to consistently drop peak
runoff flows down into the 20 to 50 cfs range (such as a very big new dam), the maximum
habitat levels that can be attained will be limited to those that can be developed by bringing
minimum flow levels up to the range than enough adults survive through low flow periods to
Pa~e 19
balance the number of fry that can survive sprin~time high flow conditions. Winter minimum
flows of 2 cfs and summer minimum flows of 4 cfs, as specified by the IFIM analysis, should
maintain the maximum aquatic habitat within Middle Boulder Creek achievable given the
high spring streamflow levels. Minimum flow levels for North Boulder Creek vary by reach,
but are in a similar range.
21. How will streamflows in Middle and North Boulder Creek change if the Carter
Lake pipeline ~vere constructed resulting in a higher quality and more reliable
supply for the Boulder Reservoir WTP and thus potentially reducing the need for
exchanges?
Staff Response:
Boulder's need to use exchanges is not reduced with either the presence or absence of the
Carier Lake Pipeline, so streamflows will not be affected one way or the other. The ability to
fully use available treatment capacity at BRWTP is not limited, now or in the future, by the
mode of raw water delivery. Sufficient flowrate capacity to fully feed the BRWTP can be
achieved from the canal, the reservoir, or the proposed Carter Lake Pipeline. In the future,
the same amount of water would be delivered each year BRWTP whether it is carried in a
pipeline or delivered only through the canal and from Boulder Reservoir. The only difference
will be in the level of treatment provided based on the source.
There is more than enough capacity at the BRWTP to treat all water available to the plant
even if no exchanges were used. The capacity of the BRWTP is designed to be 16 MGD
nominal and 20 MGD maximum in order to assure the redundant ability to produce enough
water to meet essential indoor water demands at build-out from each of the City's three water
supply systems-the BRWTP system, the Barker system and the Silver Lake Watershed
system. If no exchanges took place, the average amount of water available to BRWTP under
build-out conditions over the City's 285 year modeled period of record would be 12.3 MGD
and would range from an annual average of 8.6 MGD to 13.6 MGD. Therefore, a Carter
Lake Pipeline sized to 16 MGD for purposes of ineeting essential indoor water needs is more
than adequate for operational needs no matter what might be decided in the future about the
use of the City's exchange rights.
The Carter Lake Pipeline would improve water system reliability by providing a redundant
means of water delivery in the event of equipment failure or operational problems with the
other delivery facilities, but would rarely add to the ability to use BRW1'P capacity at times
othcr than during an equipment failure or other problem. At present, source options include
dra~~~ing~ directly from the Boulder Feeder Canal or pumping from Boulder Reservoir. Since
the canal is shut down from about November to April of each year, tiie Carter Lake Pipeline
would provide a second option for water delivery to BRWTP in the ~vinter months. If one of
the present source options is unavailable for operational reasons, such as a power outage to
the pumps or herbicide spraying on the canal, the Carter Lake Pipeline would provide the
flexibility of an additional means of providing water. It is likely that if the Carter Lake
Pipeline were built that it would be used as the sole means of supplying BRWTP at most
times, but the options of using Boulder Reservoir water or canal water would remain for use
during drou~ht or emergency.
Pa~~e 20
The increased flexibility provided by the Cazter Lake Pipeline could provide a slight increase
in the drought year yield of the City's water rights portfolio by increasing flexibility of
reservoir storage use for the City's Windy Gap water supplies. If the City is able to access its
CBT allotment directly from the storage pool in Carter Lake during the winter, the City's
winter Boulder Reservoir account can be filled with Windy Gap water each year. At present,
it is filled with CBT water from the allotment given in the yeaz that is closing. If this close-
out CBT allotment can be accessed from Carter Lake during the winter, it would no longer
need to be placed in Boulder Reservoir storage before the canal shuts down in the fall. If the
Windy Gap water that is then stored in Boulder Reservoir for the winter is not delivered into
the BRWTP over the course of the winter, it can be exchanged up to Bazker Reservoir in the
spring for later use at Betasso. The increased availability of storage space for Windy Gap
water and the increased ability to exchange Windy Gap effluent back into the City's water
system until it is fully consumed might provide a slight increase in water yield during
moderately dry periods when exchange potential exists. This in turn would allow the City to
carryover higher amounts of CBT water under the City's account within the CBT storage
reservoirs that could be used during drought periods directly from Carter Lake.
The underlying presumption of Question #21 seems to be that reducing the need for water
exchanges is a worthwhile goal. At present, there is no evidence supporting the desirability of
this goal, and there would be significant negative consequences if exchanges were reduced.
These include a reduction in the City's ability to achieve its Climate Action Plan goals due to
loss of hydropower generation and the associated carbon offsets. A new study identifying any
potential benefits obtained from reducing water exchanges and weighing them against the
costs would give valuable information about potential unintended costs and consequences
that could be avoided. Identifying the social and economic costs of the proposal to different
parts of the community would help assure that all community interests are balanced.
All existing studies show that the City's use of its exchange rights does not harm the habitat
of Boulder Creek and no benefit to habitat would result from decreased use of the exchanges.
Information was previously provided to WRAB on the question of the amount of instream
flow supplementation needed for Boulder Creek and its tributazies. As a part of designing
the Boulder Creek instream flow program in conjunction with the Colorado Water
Conservation Board, extensive studies were undertaken to establish the appropriate amount
of water to be supplied by Boulder for instream flow maintenance. Both of the most
recognized methodologies for evaluating fisheries and macroinvertebrate habitat, R2Cross
and IFIM, were used to arrive at the optimum minimum flow levels for the creek. The two
periods of greatest stress to stream species were determined to be low flow periods in late
summer and winter and the high flow periods in the spring. Based on these studies, the
present instream flow program and amount of water provided by the City to North Boulder
Creek and Middle Boulder Creek addresses low flow needs and maximizes the amount of
fish habitat that can be maintained unless the high peak flows during spring runoff are
reduced in some manner. Sediment transport studies were also done and showed that no
additional streamflow is needed for channel maintenance purposes either.
Exchange of water is necessary in some years because most of Boulder's reservoir storage
capacity is at the upper end of the system and feeds Betasso. About half of the City's water
supplies are available at the Boulder Reservoir side of the system where the Boulder
Reservoir WTP has a capacity of 16 MGD and is expected to be used in the future as yeaz-
round base-load plant. The Betasso WTP has a capacity of about 47 MGD which is needed
Page 21
during the summer months when all of Boulder's treatment capacity at both plants is required
to meet the peak daily demand. However, due to the limits on water available for delivery to
Betasso WTP, the total annual amount of water run through Betasso will be very similaz to
the total annual amount treated at BRWTP in the future. Even without use of exchanges, the
average annual daily production at Betasso WTP under build-out conditions would average
12.6 MGD and at Boulder Reservoir WTP would average 123 MGD.
The capacity of BRWTP will be used more and more as the City reaches full build-out.
Maximized use of both treatment plants throughout the yeaz will be required to meet build-
out water demands. Use of treatment capacity at Betasso WTP is presently maximized given
limits on the physical availability of water in the upper Boulder Creek basin, whether that
water is attributed to diversion under native basin water rights or through exchange.
Therefore, future water demands will be satisfied through greater use of the BRWTP and by
consistently operating BRWTP as a year-round baseload plant. Betasso WTP will carry a
portion of the baseload since it must remain in operation to assure water deliveries into Zone
3 of the treated water distribution system, but most of the Betasso WTP capacity will be used
to meet peak water demands during the irrigation season.
Use of exchanges allows greater use of the City's CBT water supplies without large and
unwarranted capital expenditures for new pipelines and pumping stations at Boulder
Reservoir and operational expenses for additional power and trearinent chemicals to run more
water through BRWTP. Following the City's first use of exchanges in 1954, the design of
water system components has assumed that river exchanges would continue to the greatest
extent possible without causing detriment to the environment. This operational underpinning
places great reliance on Betasso WTP for year-round operation and for water deliveries into
the highest pressure zone in the treated water distribution system Modifying the foundation
for the water system design at this point by reducing use of exchange rights would require
enlarging treated water transmission pipelines from BRWTP, enlarging key water
distribution pipelines leading from Zones 1 and 2 up into Zone 3, adding pumping capacity to
pump stations throughout Boulder, and increasing treated water storage capacity. This would
be a difficult fiscal position to justify.
A significant repercussion of not using the City's exchange rights would be to the cost of
providing municipal water service. The city's exchange rights have proven to be a reliable
way to move thousands of acre-feet of water yield up Boulder Canyon without investing
millions of dollars in a pipeline rmming from Boulder Reservoir up to Betasso WTP. This
higher quality water is then treated using fewer chemicals and less energy than water
delivered from the BRWTP. The water also generates electricity and the hydropower sales
revenues going to reduce bills for the City's water customers.
If use of exchanges were discontinued, it would increase the frequency of mandatory drought
water use restrictions in Boulder. This would increase inconvenience to the City's citizens
and may cause significant loss of investments in landscaping. In addition, decreased
municipal irrigation use due to drought restrictions would reduce lawn inigation rehun flows
to Boulder Creek during key low flow periods for the creek. Instream flow levels would be
harmed during the most critical drought periods. The amount of water available to satisfy
downstream agricultural users would also be decreased during drought periods due to
municipal water use restrictions as was seen in 2002. Lowered streamflows caused by
Page 22
reduced municipal lawn water rehirns in 2002 triggered senior calls by agricultural users.
These calls shut down most irrigation ditches and called out some of the City's most senior
direct flow water rights. The feedback loop caused by reduced lawn imgation returns further
reduced the City's water supply and instream flow levels.
Decreased use of the City's exchange rights would increase greenhouse emissions and work
against the City's adopted goals for reducing global warming in two ways. The City is able to
generate electricity from hydropower plants using ttte pressure developed within the upper
part of the City's municipal water supply system. These power plants generate 45 million
kilowatt-hours per yeaz which is enough to supply 8200 homes in Boulder with their annual
power needs and offset the burning of 23,000 tons of coal each year. The revenue from the
power sales provides over $2,100,000 to the City's water utility fund each year that would
otherwise have to come from increased water rates. If water exchanges were reduced, the
amount of hydropower generated would be reduced. In addition, power demands (and
associated coal buining) would increase due to the need to pump a like amount of water into
BRWTP and through pumping plants up into the City's treated water distribution system.
22. Why would separating the Boulder Feeder Canal outfall crossings not be sufficient
to address many of the contamination issues aud concerns related to the Boulder Feeder
Canal. Are there just a few sign~cant crossings that would need to separated to secure
a significant improvement in water quality risk?
Staff Response:
Initially, along the Boulder Feeder Canal (BFC), there were 60 outfalls (50 manmade and 10
bank outfalls) that dischazged to the BFC during irrigation or precipitation/snow melt events.
In 2005, four outfalls were eliminated. In 2007, it is anticipated that an additional six high
priority outfalls will be eliminated or re-routed to either go under or over the BFC and no
longer dischazge to the BFC. To date, efforts to eliminate or re-route the outfalls have been
challenging due to factors such as: re-routed outfalls needing to discharge to private property;
difficulty in getting private property owner agreement to drainage easement requirements;
and, the inability to re-route existing large concrete outfall structures due to their low
elevation which would interfere with canal flows if routed across the BFC. Provided in the
table below is an inventory of outfalls to the BFC, location, drainage azea landuse and their
current or future status.
Page 23
St. Vrain Supply (SVSC) and Bou-der Feeder Canal (BFC) outfalls 2007
Outfalls after 2007
Area ft2 Acres Canal Outfall No Land-use
1050981 24.12 SVSC 45
78221.5 1.79 SVSC 92
4751139 1.09 SVSC 187
1349467 30.97 SVSC 191
70366.49 1.61 SVSC 397
26551.9 0.60 BFC 155 Natural
19219.51 0.44 BFC 171 Nahual
11701.7 0.26 BFC 189 Natural
50109.15 1.15 BFC 204 Nahual
27079.65 0.62 BFC 207 Road
18576.62 0.42 BFC 208 Road
3343243 7.67 BFC 236 Pasture
73779.22 1.69 BFC 306 Pasture
128583.9 2.95 BFC 310 Pastute
223146.5 5.12 BFC 359 Pasture
1874734 0.43 BFC 367 Pashue
65763.64 1.50 BFC 399 Road/Pasture
107646.2 2.47 BFC 403 Pasture
141983.8 3.25 BFC 413 Pasture
1809803 4.15 BFC 416 Pasture
1670703 3835 BFC 435 Residential
20289.86 0.46 BFC 423 Residential
24674.11 0.56 BFC 429 Residential
497949.1 11.43 BFC 441 Agriculture
1413812 32.45 BFC 450 Agriculture
478147.5 10.97 BFC 455 Agriculture
1902744 43.68 BFC 459 Agriculture
10040.29 0.23 BFC 512 Road
11341.97 0.26 BFC 513 Road
19651.87 0.45 BFC 536 Natural
29628.76 0.68 BFC 537 Natural
9004.47 0.20 BFC 543 Natural
71871.67 1.64 BFC 548 Natural
686883.1 15.76 BFC 576 Natural
167054.5 3.83 BFC 570 Natural
56590.73 1.29 BFC 594 Residential
4093034 0.93 BFC 609 Agriculture
52203.63 L19 BFC 616 Agriculture
5090433 ll.b8 BFC 620 Agriculture
2175533 4.99 BFC 643 Natural
548226.6 12.58 BFC 655 Natural
Total 285.91 41
Page 24
Outfalls fixed and to be fixed fa112007
Area Acres Canal Outfall No Land-use Work Schedule
90658.06 2.08 BFC 79 Mine Graded to underpass 2005
Reclamation
27456.29 0.63 BFC 90 Mine Graded to underpass 2005
Reclamation
242254.1 5.56 BFC 357 Residential Graded to crossing fa112007
34387.23 0.78 BFC 349 Natural Cttaded to crossing fa112007
199743.4 4.58 BFC 364 Pasture Constnxct crossing fa112007
418615.6 9.61 BFC 372 Agriculture Crossing fa112007 pending landowner
approval
31618.2 0.72 BFC 370 Agriculture Graded to crossing fa112007
489241 11.23 BFC 379 Agriculture Graded to underpass fa112007
523056.9 12.00 BFC 525 Agriculture Graded to crossing 2005
1037727 23.82 BFC Bank Mine Graded to underpass 2005
Reclamation
Total 71.01 10
Bank Outfalls
Area ft2 Acres Canal Outfall No Land-use
5022819 1.15 SVSC Bank
152878.4 3.50 SVSC Bank
64585.46 1.48 SVSC Bank
141540.8 3.24 SVSC Bank
6533713 14.99 SVSC Bank
24258 0.55 SVSC Bank
34008.96 0.78 SVSC Bank
30515.78 0.70 SVSC Bank
3785.08 0.08 BFC Bank Natural
Total 26.47 9
In addition to contamination from agricultural and storm water outfalls data (E.coli) indicate
that the canal prism or depression itself is a potential source of contamination during storm
events. This impact was identified during the 24 hour synoptic sampling event conducted in
2002, where bacteria contamination was identified although no flow from outfalls to the BFC
were identified, but precipitation did occur during the sampling event. Canal maintenance
also exposes the water supply to organic and inorganic contaminants from herbicide
application and algae control.
The following aze additional water utility actions that have been put in place to protect the
BFC and the Boulder Reservoir Basin water supplies from potential contaminants.
Boulder Feeder Canal
• Recreational event patrols and coordination before and after the events to reduced the risk
of contaminants entering the drinking water supply.
• On going sowce water monitoring and special studies.
Page 25
Watershed delineation and identification of potential sources of contamination.
New no trespassing signs posted and additional locked gates near the canal intake
structure.
Boulder Reservoir
• Buoys around the intake which provide a 200 foot buffer. Elimination of 6 floating
platforms, some of which were near the treatment intake. A ten foot curtain has been
installed azound the intake. This was done to reduce the amount of dissolved manganese
and bottom sediment entering the treatment facility.
• Watershed delineation and identification of potential sources of contamination. This
effort shows where potential sources of contamination are in relation to surface water and
the treatment intake.
. New secured port-a-let at the trail head on the northwest side of Boulder Reservoir. A
motor boat and trailer cleaning station is being proposed for incoming boats to Boulder
Reservoir. This would reduce the risk of potential invasive species introductions which
would significantly impact both recreation and the drinking water supply.
• The Boulder Reservoir Management Group meets quarterly to discuss activities around
the reservoir and management options. This group is comprised of people from parks
and recreation, open space, Northern Colorado Water Conservancy District, division of
wildlife and utilities.
• On going source water monitoring and special studies.
Page 26
Attachxnent 1
Criteria for Categorizing Services:
Essential
• Programs, services or facilities essential to ensuring the health and safety of the
people and property in the community and municipal corporation.
• Services insuring the integrity of the most fundamental responsibilities of
government.
• Programs or expenses that aze legally mandated by federal or state law or City
Charter.
• Investments that contribute the most to achieving the core mission of a department.
• Businesses the City of Boulder is required to be in and/ or essential services that no
other entity provides.
• Actions required by obligations such as bond covenants, laws and ottter requirements
in order to avoid fines or penalties.
Desirable
• Services that enhance programs or facilities in ways that advance desired community
values.
• Services that enhance essential services or quality of life improvements.
• Funding for ongoing operation, maintenance and replacement of an existing facility,
infrastructure, program or service.
• Services valued by the community and created by the legislative action of the Boulder
City Council.
• Actions required to meet Council's adopted budget and financial policies.
• Programs maintained as "seed corn" to provide a base for restoration in an economic
recovery; maintaining core elements of a program of higher priority to make future
restoration possible.
Discretionarv
• Creates or maintains discretionary services/facilities that serve limited purposes or
specialized interests.
• Programs desired by the community but not required to provide or enhance an
essential service.
• Services that people could obtain through other means, private or other govemmental
and non-profit agencies.
Page 27
Attachment 2
Summary of Boulder Feeder Canal Outfall Crossing Meetings Held on May 10 and 18, 2007
May 10, 2007 Meeting
People Present:
Roger Sinden (NCWCD)
Jim Struble (NCWCD)
Bret Linenfelser (COB utilities water quality)
Jim Shelley (COB utilities water quality)
John Damico (COB open space real-estate)
Doug Nucomb (COB open space real-estate)
Bob Crifasi (COB open space water resources)
Susane Webel (landowner)
Wonda Clyncke (landowner)
The purpose of this meeting was to meet with the various parties that would be involved with
funding and constructing outfall crossings over the Boulder Feeder Canal (BFC). The meeting
also included one current land owner and one land care taker. The outfalls evaluated were
selected based on their high priority and potential to discharge runoff from irrigation or storm
events and snow melt.
Bennett Land (future Open Space property)
City Open Space is purchasing the Bennett property in which Wonda Clyncke is the care taker.
Outfa11364 will be brought over with no issues with full agreement from Open Space, Wanda
Clyncke and Bill Bennett (land owner). Outfa11359 is a large concrete structure designed for
floods but it was determined by Northern Colorado Water Conservancy District (Northern) that
this outfall is set too low to construct a crossing without interfering with high canal
flows. For now Outfa11359 will not be addressed. Outfalls 349, 370 and 357 will be taken care
of as best they can by grading the land surrounding the outfalls to an existing crossing. It is
anticipated that grading can be conducted by Open Space with Utilities input.
Susanne Webel Land
Two outfalls upgradient of this property are on the high priority list and drain land on the west
side of the canal from land owned by Alden Fidao. Outfall 379, with landowner (Alden Fidao)
approval, could be graded to an existing drainage to the south that goes under the canal. This
would eliminate the need to construct an extension of the outfall over the Boulder Feeder Canal
which would discharge on Susanne Webel's property.
Outfa11372 can be designed to cross the canal but Susanne Webel requested that the dischazge be
routed to a high point on her land that would require surveying by the city and the construction
of a long conveyance pipe on her property. This complicates the project since this would add to
the cost of the project plus the ciTy would then be involved with construction on Webel property
versus just on Northern Colorado Water Conservancy District ROW. What we're going to
propose to Susanne Webel is that we will build a crossing with a directional header on her side of
the canal and then she would be responsible far conveying the water to her preferred location if
she wants. If she doesn't agree with our proposal we propose to work with the upgradient
Page 28
irrigating landowner (Alden) to be more efficient with his field flooding irrigation practices and
mitigate flow to Outfa11372.
Status of Drainage Easement
John Damico with Open Space is working on official drainage easement agreement that would
be used between the city of Boulder and the landowners involved. Once the easements aze
completed city Utility staff will review and provide comment, if needed. A copy of the drainage
easement will be sent to Susanne Webel for her review.
Cost and Schedule
After confirming what Outfalls will be routed over the BFC and what land grading needs to be
completed, WQES staff will meet with NCWCD to initiate the design and obtain preliminary
costs. It is anticipated that improvements to Outfalls 364, 349, 370, 357 and 372 will be
completed by the end of the yeaz.
May 18, 2007 Meeting
People Present:
Jim Shelley (COB water quality)
Scot Gillespie (COB water quality)
Jim Struble (NCWCD)
Alden Fidao (west side landowner)
This meeting was held to discuss the possibility of diverting flow that goes to outfal1379 to an
existing outfall to the south which is already routed under the Boulder Feeder Canal (BFC).
Land owner (property west of BFC which drains to outfa11379) Alden Fidao agreed to re-
grading a portion of his property to divert flow away from outfa11379 as long as his alfalfa field
isn't damaged. Jim Struble thought that the drainage diversion could be placed just inside the
fence line on Northern's easement and may not affect Alden Fidao's property. Jim Struble is
going to talk with Dennis Baker from Northern about having the area surveyed. Alden Fidao
also stated that he did not have any problems with constructing a crossing for outfall 372 (just to
the north of outfall 379) over the BFC.
Jim Shelley talked with Dennis Baker on May 21, 2007 and Dennis is planning on surveying the
azea this week. As soon as the survey information is available Jim Shelley will call John Damico
with Open Space and Mountain Parks so he can call Susanne Webel with the plan and agreement
documents.
Page 29
~ ,--~,~'~~~" ~
Q BLAGK & VEATCH
* 6oildinpaW(~K~(jal~Meroncen
ENEflGY . WRTER • INFOBMATION . 66VERNMENT
City of Boulder, CO
BRWTF Multi-barrier Approach Study
Peer Review Responses
B&V Project #144922
B&V File A-1.3
Ms. Annie Noble
Utilities Project Manager
City of Boulder
1739 Broadway
Boulder, CO 80306
June 19, 2007
Dear Annie,
Attached are the results of an independent decision model developed by Mr.
Kelly Denatale of the City of Boulder Water Resources Advisory Board (WRAB) to rank
alternative multi-barrier water delivery alternatives outline in the Black & Veatch report
entitled "Integrated Evaluation of Boulder Reservoir Water Treatment Facility Source
Water Protection and Treatment Improvements Study" dated June 18, 2007. The
relative weights of the 8 criteria contained in this model were evaluated by four Water
Resources Advisory Board Members using the pair-wise comparison technique. The
water delivery alternatives from the Black & Veatch report were scored against the
WRAB decision model by Black & Veatch and by Mr. DeNatale. Tables 1 through 5
give the relative performance scores of alternatives using the WRAB model as
evaluated by Black & Veatch, whereas Tables 6 through 10 give the relative
pertormance scores using the WRAB model as evaluated by Mr. DeNatale. The WRAB
decision model criteria and pair-wise comparison weighting forms follow page 18.
Very Truly Yours,
BLACK & VEATCH CORPORATION
(/~i~`L~vL..-. ~ ~Jaa~~~
Christopher J. Tadanier, PhD
Process Specialist
WATER RESOURCES ADVISORY BOARD DEC1SlON MODEL
Biack & Veatch A/ternative Scores
Table 1
WRAB Decision Model with Black & Veatch Alternative Scores
Decision Scores Decision Scores
Altemative WRAB Member~~~ City SWff~2~
No Processes A B C D
1 BFC/BR w/ CI02 0.693 0.711 0.696 0.786 0.512
2 BFC/BR w! CI02 and UV 0.668 0.675 0.657 0.707 0.573
3 BFC/BR w/ CI02, GAC and UV 0.579 0.554 0.557 0.493 0.606
4 BFCIBR w! C102 and MFIUF 0.550 0.543 0.575 0.554 0.554
5 BFC/BR w! C102 and AOP 0.714 0.707 0.718 0.668 0.603
6 CLP w/ CI02 0.882 0.882 0.896 0.861 0.942
Notes:
~'hNRAB Decision Model
~z~City Staff Decision Model
WATER RESOURCES ADVISORY BOARD DECISION MODEL
Black 8 Veatch AlMmafive Scores
Table 2
WRAB Per/ormence Criterb Walghb antl Water Delivery Alternative Scores
WRAB MemMr A
Yeld entl Rebability 6 0.214 5 5 5 5 5 10 Plt 2: BFGBR w/ CI02 antl W
ions 0 0.000 10 7 3 5 6 10 3: BPGBR w/ CI02, GAC an0 W
y/EnPorceable Stentlartls 7 0.250 7 8 9 7 70 9 A114: BFC/BR w/ CI02 antl MFNF
iary/AestheitcStanderGS 3 0407 5 5 5 5 8 1a AH5: BFGBRw/CI02entlA0P
~mentalEnhancement 4 0.143 5 4 4 7 5 1U AIIB: CLPw/q02
abNty 2 0071 10 9 7 8 8 8
e..., v nm~ ~n 1n 1~ 1~ 10 5
by WRAB Member
WATER RESOURCES ADVISORY BOARD OECISION MODEL
B/ack 8 Veatch Altemative Scores
Table 9
WRAB Perfortnance Crilena Waights antl Wa[er Delivery Alternative Scoros
WRAB Member B
and Reliability 5 0.179 5 5 5 5 5 10 N12. BFC/BR w/ CI02 antl W
0 O.OUO 10 7 3 5 8 10 A113 BFC/BR w/ CI02, GAC antl UV
>rceable Standards ~ 0.250 7 8 9 7 10 9 A114: BFC/BR w/ CI02 antl MFNF
~esiheilcStandartls 3 0107 5 5 5 5 B 70 A115: BFC/BRw/CI02andA0P
IalEnhencement 4 Od43 5 4 4 1 5 70 AH6' CLPw/CI02
' 3 0707 10 9 7 8 8 8
7 0036 10 10 10 ta to 5
by WRAB Member
bv B&V based on V
WATER RESOURCES ADVISORY BOARD DECISION MODEL
B/ack & Veatch Altemative Scores
Table 4
W RAB Pertomiance Cnhria Waighb and Water Delivery Albmative Seorea
WRABMemberC
and Relabihty
arceeble SWntlartls
0250 5 5 5 5 5 10
O.1W 1U 7 3 5 8 70
0.779 7 8 9 7 70 9
0.214 5 5 5 5 8 10
0.038 5 4 4 7 5 10
0000 70 9 7 8 8 8
BFGBRw/ CI02 antl UV
BFC/BR w/ CI02, GAC and UV
BFC/BR w/ CI02 entl MF/UF
BFC/BR w/ CI02 and AOP
by WRAB Member
WATER RESOURCES ADVISORY BOARD DECISION MODEL
Black 6 Veatch Altemafive Scores
Table 6
WRAB Per/o~manca Cribrla Waights antl Wabr Delivery Allema4ve Scorea
WRAB Member D
V
~ ' F
R w
h ht
c St
antlnrtls I ~ I p /
CI02 arntl OP
~ 5. CLGB
~
~
~ E 8 ~
b I ry 4 0
1
43 10 9 7 8
by WRAB Member
bv B8V beseG on WRP.B sconna insirucbons
WATER RESOURCES ADVISORY BOARD DECISION MODEL
Black & Veatch Aliernative Scores
WRAB Decision Model
Alternatives Scoring Summary Tables
Mana e Costs NPV Score
Altemative Treatment
Strate Score Comments: NPV Costs
t CIOz 10 $520 10
2 CIOi+UV 8 $9.28 8
3 CIOz+GAC+UV t $53.41 1
4 CIOZ+MF/UF 5 $29.25 5
5 CIOz+qOP 5 $26.94 5 ,
6 CLP + CIOZ 7 $17.12 7
NPV: Net present value including capital, O&M, and financing
Yield and Svstem Reliabilitv Reliabiliry Yield
Altemative Treatment
Strat Score Comments: Reliabiliry and Yield
1 CIOs 5 -4 -1
2 CIOz+UV 5 -4 -1
3 CIOz+GAC+UV 5 -4 -1
4 CIOz+MF/UF 5 -4 -t
5 CIOz+AOP 5 -4 -1
6 CLP+CIOz 10 0 0
Base Score 10
BFC/BR -4
CLP 0
Reliabiliry: Redundancy of water sources to BRVJTF
Yield: Availability of Winter storage in Carter Lake is superior to Boulder Reservoir
6
WATER RESOURCES ADVISORY BOARO DECISION MODEL
Black 8 Veatch Alternative Scores
System Operations ' Processes Equipment Consumables
Altemative Treatment
Strate Score Commants: Additional processes, energized equipment, consumables
1 CIOz 10 0 0 0
2 CIOz ~ UV 7 -1 -1 -1
3 CIOz+GAC+UV 3 -2 -2 3
4 CIOz + MF/UF 5 -1 -2 -2
5 CIOz+AOP 6 -1 -2 -1
6 CLP+CIOz ~0 0 0 0
W -1 -1 -1
GAC -1 -1 -2
MFIUF -1 -2 -2
AOP -1 -2 -1
Primarv SWndards Barriers
Altemative Treatment
St2te Score Comments: Prima Standards, source consisten
ry ~y.robusiness
1 CIOz 7 65
~n
-~~
2 CIOz' UV 8 7.5 b~,.~a
Score= x10
3 CIOz+GAC+UV g g,0 ~Nb~1e~ -0~
4 CIOi + MF/UF 7 6.5 n~,m~,= # barriers in altemative
5 CiOz + AOP 10 9.5 Ne.,,,,r- max # barriers in altemahves
g CLP+CIOz 9 8.5
Barriers: Number of primary contaminant barriers from Figures in 8&V Draft Report Chapter 5
WATER RESOURCES ADVISORY BOARD DECIStON MODEL
Black & Veafch Alternative Scores
SacondarvlAesthetic SWndards Barriers
Alternative Treatment
Strate Score Comments:
1 CI02 5 2.5 / )
`nb°'""-~
2 CIO,+UV 5 2.5 " x10
Score=
-~~
~N
3 CIOz+GAC+UV 5 3A n~.
4 CIOz + MF/UF 5 2.5 ne.me~ # barriers in atternative
5 CIOz +AOP 8 4 5 N~,,,,,~ max # barriers in alternatives
g CLP+CIOs 10 5.5
Baniers: Number of secondary contaminant barriers from Figures in B&V Draft Report Chapter 5
Enviromm~etal Enhancement EneraV SCOre
Akernative Treatment
Strate Score Comments: Carbon Footprint Differenee
1 CIOz 5 $22,750 5
2 CIOz+UV 4 $28,663 4
3 CIOz+GAC+UV 4 $31,605 4
4 CIOz+MF/UF t $43,763 1
5 CIOz+AOP 5 $22,750 5
g CLP+CIOz ~0 $0 10
8
WATER RESOURCES ADVISORY BOARD DECISION MODEL
Black 8 Veatch Alternative Scores
Public Acceptance Const Ops
Alternative Sta~ent Score Comments: Operations eonsideres chemical delivery and usage
1 CIOz 10 0 0
2 CIOz+W 9 -1 0
3 CI02+GAC+UV 7 -2 -1
4 CIOz+MF/UF 8 -1 -1
5 CIOi+AOP 8 -1 -1
6 CLP+CIOz 8 -2 0
Consl Ops
PermiHing
UV -1 0
GAG -1 -1
MF/UF -1 -1
AOP -1 -1
CLP -2 0
Boulder C Larimer C 404 Others
Attemative Treatment
Strate Score Comments
1 CIOz 10 - 0 0 0 0
2 CIOz+UV 10 0 0 0 0
3 CIOz+GAC+UV 10 0 0 0 0
4 CIOz+MF/UF 10 0 0 0 0
5 CIOz+AOP t0 0 0 0 0
g CLP+CIOz 5 -2 -2 -1 0
Boulder County Pertnit -2
Lar~mer County Permit -2
404 Permit -1
Other Participants Impacls 0
9
WATER RESOURCES ADVISORY BOARD DEC/S/ON MODEL
DeNata/e Alternative Scores
Table 6
WRAB Decision Modet with DeNatale Alternative Scores
Decision Scores Decision Scores
Altemative WRAB Member~~~ City Staff~=~
No Processes A B C D
1 8FC/BR w/ CI02 0.796 0 802 0.780 0 863 0 512
2 BFC/BR w/ CI02 and UV 0.793 0.795 0.773 0.838 0.573
3 BFC/BR w/ CI02, GAC and UV 0.707 0.677 0.695 0.623 0.606
4 BFC/BR w/ CI02 and MF/UF 0.739 0.723 0.745 0.730 0.554
5 BFC/BR w/ CI02 and AOP 0.775 0.759 0.759 0.727 0.603
6 CLP w/ CI02 0.739 0.738 0.798 0.727 0.942
Notes:
~'~Decision Scores based on model weights and alternative scores provided by Kelly DeNatale on O6 June 2007
~2~City Staff Decision Model
10
WATER RESOURCES ADVISORY BOARD OECISlON MODEL
DeNatale Alfemative Scores
Table 7
W RAB Perfo~mance Criteria Wal9hb antl W ater De1Wery AftemnWa Scoras
WRAB Member A
Vieltl antl Reliabibry 6 0214 8 5 8.5 8.5 B.5 8.5 7.5 Wt 2. BFC/BR w/ CI02 anE UV
lans 0 0.000 9 8 5 8 5 10 PAt 3: BFC/BR w/ C102, GAC and UV
y/Enforceable StanEartls 7 0 250 7 8 9 9 9 9 All b. BFC/BR w/ CI02 antl MFNF
tlary/AesNeitc Slantlartls 3 0.707 5 5 8 5 7 B AI15: BFC/BR w/ CI02 antl AOP
omentalEn~ancement 4 0.143 7 8 8 5 6 6 Alt6: CLPw/CI02
zbtlily 2 0.0]1 70 10 9 9 9 5
e~~ z a.o~i ~a io io io io 5
Assig^ed by WRAB Member
11
WATER RESDURCES ADVISORY BOARD DECISlON MODEL
DeNatale Alternative Scores
Table 8
WRAB Per/ormance Criteria Welghts antl Water Delivery Altemalive Scores
WR4B Member B
antlReliabiliry 5 0.179 8.5 8.5 B.5 8.5 8.5 7.5 AIt2 BFC/BRw/CI02andUV
0 0.000 9 B 5 B 5 10 A113~ BFC/BR w/ CI02, GAC antl W
xceable Standards 7 0150 7 B 9 9 9 9 A114: BFC/8R w/ CI02 and MPNF
~esiheRCStantlartls 3 0.707 5 5 6 5 7 9 AI15: BFC/BRw/CI02entlAOP
IalEnhancement 4 0.143 7 8 6 5 6 6 Alt6: CLPw/CI02
~ 3 0.107 10 10 9 9 9 5
by WRAB Member
12
WATER RESOURCES ADVISORY BOARD DECISION MODEL
DeNatale Altemative Scores
Table 9
WRAB Pertom~ance Criteria Weighls antl Water DeliveryAltamative Scorea
WRAB MemEer C
Vieltl antl Reliabiliry 7 0.250 8.5 8.5 B.5 8.5 8.5 7.5 A112' BFC/BR w/ CI02 antl UV
~ons 3 0.107 9 8 5 8 5 10 AH 3~ BFC/BR w/ CI02, GAC antl UV
y/Entorcea~le Slantlartls 5 0.779 7 8 9 9 9 9 Alt 4 BFC/BR w/ q02 antl MFNF
tlary/AesiheitcStandards 6 0.214 5 5 8 5 7 9 AltS BFC/BRw/CI02antlAOP
+menWlEnhancement 1 0.036 7 6 6 5 6 fi P118. CLPw/C102
ab~lity 0 0.000 10 10 8 9 9 5
by WRAB Member
13
WATER RESOURCES ADVISORY BOARD DECISION MODEI
DeNatale Altemative Scores
Table 10
WRAB Pertortnanee Cri[eria Welg~ta and WaUr Delivery Nternatlva Scorea
WRAB MemEer D
Yeltl antl Reliabil~ry 5 0.179 8.5 8.5 8.5 8.5 8.5 7.5 A112. BFC/BR w/ CI02 and UV
ians 2 O.W7 9 8 5 8 5 10 AI13~BFC/BRw/CI02,GACantlW
y/Enforceable SfanGards 5 0.179 7 8 9 9 9 9 PA14: BFGBR w/ C102 and MFNF
tlary/Aes~heilc SlantleMS 1 0 036 5 5 8 5 7 9 FJt 5: BFC/BR W/ CI02 and AOP
nmental Enhancement 3 U.1 W 7 6 8 5 8 6 P118: CLP w/ CI02
abiliry 4 OA43 10 10 9 9 9 5
by WRAB Member
14
WATER RESOURCES ADVISORY BOARD DEC/S/ON MODEL
DeNatale Alternative Scores
WRAB Decision Model
Alternatives Scoring Summary Tables
82WTF MWti-Bartior Approaeh Daeision Analysis Summary
CompanHVe nst prasant value eoat of aonstruetlon and OSM usin0 sams cest basis antl seurca
Mana aCOSb foreom arison
npina av s
No Proc~ss~s Seen Seoro NPV Gosls Nota en R~visa05eore
NPV cost from Black & Vealch Linear scwe basetl on hgM1est
t BPCIBR wI C102 10 10 $ 520 and lowesi cosis
NPV cost from Black & Veatch Lnear score basetl on ~ghest
2 BFGBR w/ CI02 an0 UV 8 9 $ 9 2B and bwest cosis
Watlmgfeetl~ecklromoutsi0emnsultanl Full-0etlGAC
appears to be overkill fa tlMerence in waler quality ~elween
CaM1er Lake aM BFC/Boulder Reservo~r There is iw entlence
3 BFGBR w/ C102, GAC and UV 1 1 E 53 41 of increase in o anirs
NPV cost hom Black & Veatch Lnear swre based on hghest
4 BFC/BRw/CI02antlMFNF 5 5 5 2925 andlowestcosts
NPV cost han Black 8 VeatW Linear score basetl on hghest
5 BFC/BR w/ CI02 antl AOP 5 5 $ 2649 and lowesl wsts
T~is NPV must be checketl ro make sure Nat same 88V
plennn8lavel cwl approach is used hr CLP as fw other
altematrves ThlscoslwasapparentlylakenfromlMegracost
summary B8V cost also includes rletlit for resitl~al IRe o!
6 CLPw/CI02 7 ~ S 1712 pipelineafter20yearperiotl
Maximiz~ wabr yisld antl syatam roliability pivsn th~ potential tor syatam failures sueh as
Mai~mi:a Wa»r Yfaltl and Syatam coMamMat{on e1 a wner sourca, olimata ehmpe, Fmitad exehmpa potmtial, atc. Fwtor in Ma
Reliabili loeation a1Rrm yiald su liu wiM Ne abili to tlinctlylreat Ne waNr.
av~s~
Oripinal Revised Rsvisetl Seon
No Proeeases Score Seoro SeoreYlald RNiabiliry NoteonRavisWScore
No bss of Vieltl since Fartners Dtlch shares and Boultler
Reservoir Srorege are available every year and drougM
conddions tlo nol have to be enticipateC for use o( these ngnts,
Two saurces of delivery are available Boultler Reservoir storog
1 BFC/BR wl CI02 5 B 5 10 7 is atl uate to meet wmter tlemantls of 15 MGD
2 BFC/BR wl C102 antl UV 5 8 5 10 7 Same as Attematrve N1
3 BFC/BRw/CI02,GACandW 5 BS 10 ~ SameasAkemahve#1
4 BFCIBRw)q02antlMFIUF 5 BS t0 7 5a~neaSAltematrve#t
5 BFC/BRw/p02antlAOP 5 85 10 ~ SameasAkematrve#1
Loss of YreW since Farmers Ditcli s~ares antl eoultler Reservoir
stofage will only be usetl tluring drought contlihons. Atlds one
6 CLPw/CI02 10 75 5 10 mofedebveryaptionoverBFC+BOUIderReservmr
15
WATER RESOURCES ADVISORY BOARD DECISION MODEL
DeNatale Alfernative Scores
Sim li O rMlons Previd eforaaseo7a stemo araHOns
p na avise
No Proeuses Seon Swn Nole on Revisetl Seoro
Sama Ueatmant process but shghiN mwe invoNed operatans
1 BFC/BRw/CI02 10 9 thanCLPtluatova in weter uali
2 BFC/BRw/CI02antlUV 7 8 ModemUVSStemsarem~nimalmaintenance
GAC requies perrotlic regeneratan or replecement. Atltl one
moreuntlpracess,~u[operalwnisnolwmplex Unlikalyt~at
GAC is needeA Oasetl on tlMerence in weter quality behveen
3 BFGBR wl CI02, GAC entl UV 3 5 CaMer Lake and BFCBaulder Reservoir
MemMane BlVetion cen be highly aummaleE entl reqmres
minimal opetatbr invoNemenL More Wmps aM valves
4 BFCBRw/CI02anAMFNF 5 8 Posihvabartiara ainslNrEW antl h ens.
Atltls one more unil process. Unlikety tl~at AOP is neetletl basetl
on tlMerence m watM qualdy betwem Cartar Lake aM
5 BFGBR w/ CI02 entl AOP 6 5 BFC/BOUltler Reservoi
ese ase. ssumplron is 1 a ere wi nol any anges in
Catler Lake weler qualM1y ove~ time and TOC will not require
6 CLPw/CI02 1U 1~ atltl~bonaltrestmentprocasses.
MaximB~ M~ abiliry to me~t SaH Utlnkinp Wabr Acl n0~latlons, factotln9 in roliability ef aaeh
Ensunm~~tln wabrqualityropulalions aoure~wHVOrlrea6nanlbarti~rundsr tenNWeouro~wab~contlltlona
p na ~v~s~
No Prowsaaa Seoro Seon NobonRSVISWSeon
Base case trealmenl thal can help minimize ~BPS Chorites era
formetl Ihmugh the CI02 pracass antl are a repulatetl
1 BFC/BRw/CI02 7 7 contaminaMihatmuslbemonitored
2 BFC/BRw/q02antlUV 8 8 Atltlitwnalbamerfa eth ens.
3 BFC/BR w/ CI02, GAC erM UV 9 9 Additwnal bamerefor h ms antl or enics
4 BFC/BRw/CI02erWMFNF 7 9 AGtlRwnalbamersforturbitli antl aUwens
Adtlkional bartiers for imbidity antl pathogens. M~mm~us DBP
fortnetwn Also a bartier tor mirsopollWanls, which are not a
primary or secontlary slantlaM No entlanca ihal
micropollutanls are a will be a concem wiN reasonable
5 BFC/BR w/ CI02 antl AOP 10 9 mana ement of BFC.
elies on assumptnn o rw ega ahon m source water qua iry
from Carter Lake Minun¢es nsks Gom BFC or Boultler
Resenoir cvicept for tlrougM. No adAitbnal barners for Wrbitlity
6 CLP w/ CI02 9 9 spikes, pathogens a agamcs
16
WATER RESOURCES ADVISORY BOARD DECISION MODEL
DeNatale Alternative Scores
Provide for high qwliry water that will eonsistanUy ma~l aU eustomar asNatic axpeebCOns and
Providesxeaptionallreatedwabrqualiry atldmsunrepulaNdeonbminanbMatmayornotMropulatedind~~fuNnwwoultlbeatvery
Mat exeeeES slandards low levals on an inhs uanl basis
gma ev s
No Proeusaa Saon Seon NM~ on RsvlseA Seon
Process wn effectnely etldress dissoNeE metals dae ro
1 BFGIBR wl C102 5 5 raservoa azaxis but will nol atldress svHates and TOS
Process wn e(fectnely atldress dissolvetl metals tlue to
2 BFC/BR w/ CI02 and UV 5 5 reservoir arwxia bul will not address sulfatas antl TDS
Process can efFechvely address Qissolvetl metals due to
3 BFC/BR w/ CI02, GAC entl W 5 6 resenoir anoxie antl T80 Cut will not adtlress sulfates and TDS
Process can eHeIXrvely atltlress dissolvetl matals tlue to
4 BFC/BR w/ CI02 antl MF/UF 5 5 reservoir anoxia dR will nol atlOress suMetes and TDS
Process wn efFectrvely aAdress QissoNed melels due to
resenoir anoxie, uriregulated wnlaminanis such as entlovrtre
5 BFC/BR w/ C102 antl AOP 8 7 tlis~u ors antl T80 bul wAI not address suMates anG TDS
BaulAer Reservoir suppN is evoideE except for tlroughis so
suHates antl TDS impacts are minim¢etl. Wntly Gap aM MoRat
Firtni~ Prajects and West Sbpe tlevelopment have ihe polentiel
to mcrease polluWnt wncentrat~ons in CBT suppty anE thus
fi CLP w/ CI02 70 9 Carter Lake
Prot~ction or anhane~m~nt of land and watar habitats antl nseure~a antl ntlueing axialinp antl
Maximiza Environmanlal Enhana~ment N1un pollutlon sourc~s Oselnwida
nua
Ori9~~al Revisad Enarpy
No Proeessas Seore Scoro Usags Nob on Ravisad Scon
Assumes some Ees~c BMP's along Boultler Feetler Canal
1 BFC/BRw/C102 5 7 $ 22,750 cou letlwithstret ¢G assesWithmawBMPs
Assumes some basic BMP's alon8 Boulder Feetler Canal
2 BFC/BR w/ C102 and UV 4 fi $ 28,663 ca~ IeC with stret ic C asses wilh ma or BMPs
Assumes sane basic BMP's alag Boulder Feetler Canal
3 BFC/BR w/ CI02, GAC antl UV 4 6 $ 3L605 cou led wM sVat w C asses wrth ma or BMPs
Assumes some basic BMP's along Bouker Feeder Canal
4 BFGBRw/CI02andMFNF 1 5 $ 83,763 cou ledwithstrat icb asseswkhma'orBMPs
Assumes some basic BMP's abng Boultler Feeder Canal
coupled wMh sVateg¢ bypasses with ma~or BMPS Enerpy cosl
5 BFGBR w/ CI02 antl AOP 5 6 $ 22,750 seems low com aretl ro Attemative 2 antl neetls to Ee checkeC
Assumes m~n~mal bypasses abng BFC untA C~P ~s consVUCted
Most sgndiwnt pollut~on sources woulC not be mitigated ~ut
woultl Oow into Boultler Reservoir impacting rec users antl
downstream Boultler Creek domestic users such as Ene antl
Layayette SgnRwnt lantl tlisturbance createtl Ey 20 i/-pipeline
6 CLPw/CI02 70 6 $ constmc[ion. GravM1yOavtoBRWTFexcepidunngdroughts
17
WATER RESOURCES ADVISORY BOARD DECISION MODEL
DeNatale Alfernative Scores
Muimiza Aeee abili Maxlmize aee~ abill Ey limil~n tli sNrbanees antl other im acts to naf hbors, eommuters, etc.
npina ev s
No Processas Seore Seoro NotaonReviBadSeero
1 BFC/BRw/CI02 10 10 Basecasebrallaltematnes
Negilbileimpacts(orUVtlehveryandinstallation Noimmediate
2 BFGBR w/ CI02 aM UV 9 10 resitlenhal nei hEOrs. No adtlihonal hazartlous chemicals
Veryminorimpaclstordeliveryentlinstellatwn Noimmetliate
3 BFGBR w/ CI02, GAC antl UV 7 9 residential ne~ ~bors. No additanal hazartlous chamicals
Veryminorimpactsfartlalrveryantlinslallatbn Noimmetliale
4 BFC/BR w/ C102 antl MFNF 8 9 resiEentiel nei hbors. No adEltbnel hezartlaus chemicals
Verymirwrimpectsfwdeliveryantlinstallation Noimmediate
5 BFGBR w/ CI02 and AOP 8 9 resitlenhal nai hbors No adAdionel hezartlous chemicals.
ign cant isiupiwno V ican neg rs uetoconsWCtion
along 20 t/- mik wrridor, even wiNin exishfg ROW. Same new
6 CLPw/CI02 8 5 ROWreqmretltotlelrvertoBR`MF
Timdin~sa/Eas~ofParmLLtinB NsM br 7047, 404 or oth~r loeal, abta or fatlanl p~rmib, abiliry lo d~livar proj~et by th~ tim~
tlis annsaOM.
No Proeuses .~e~~
Seore .~,.
Seore
Note on Revisad Seoro
1 BFCBRw/CI02 10 70 No rmksre mred
2 BFGBR w/ C102 antl UV 10 10 No ermrts r uiratl
3 BFCIBRw/CI02,GACanOUV t0 10 No ermilsre uired
4 BFC/BRwIC102antlMFNF 10 10 No ermitsr ui~ed
5 BFC/BR w/ CI02 antl A0P 10 10 No ermi~s r uvetl
fi CLP w/ CI02 5 5 Boultler antl Larimer Counry 1041 and Caps 404 permils likely
18
Boulder Reservoir Water Supply and Treatment Suggested
Objectives
Objecfives Descrlption Exampfe Criteria Notes
W hat are the relaWa capi[al costsT
How do costs chenge'rf other partlcipanls drop
out?
Comparative net present value cost of NPV af aRamative (capital and What are tM1e expec[ed staff raductions or
Manage Costs consWclion and O&M using same cost pgM I
~ ncreases7
besls and sourca for comparison How do the O&M cosfs compare9
Are Ne wst estimates made using similar unk
costs and engineeringlconlingency facotrs to
ensure an "apples to epples" comparison7
Maximize water yleld and sys[em reHability Qualitative measure of overall What is the 8rm yield of Boulder's system
given the potenGal for systeM failures such
t ~~m reliability, consldering under various hydrology and ctimate change
Mazimize Water Ylek! and e
as contamination of a water source, clime locations of source of supply and scenarfos7
System Raliability change, Ilmlted exchange potential, etc. y~atment, including selected How dapandent Is yield upon exchanges to
Factor in the location of firm yleld supplies criteria from Table 2 Betasso to delNer watar7
wiN the abflRy to directly treat the water. .
How many pumps and other mechanical
Simplify Operations Provkle for ease of system operations Use selected critaria from Table systems are InvaNed7
3 Have we Improvetl or reduced ease of
operatbns and worker safety?
~ Abtliry to consistantly deliver
Maxlmtze the ability to meet Safe Drmking treeted waterthat can meet water
qually standards givan potenUal Can the source v/ater be effecUvely treated to
'
Ensure meeting water quality WaterAct regulations, fectoring In reliability
~eriatlons in supply and potentlal ~el
~abty meet SDWA stendards7
regulations of each source vrater or treatment bartier
human or mechanical ertor H~ rohust are the treatment processes to
under potenUal source water condHions .
Include criteria from Table 1 that potential upsets in source water quality?
involve SDWA prlmary standsrds
Qualllatlve measure 6asad on
Provide for high quality water that wfll TDS, suNates, potentiai for taste Are all customers in Boulder recelving
COnsistently meet ell customer esthetic and odor events antl likelihood of accepta6le quality wataR
Provide exceptional treated expac[etlons and address unregulated other unregulatetl contaminants. Wha[ is the potential for customer complaints
water quallty lhat exceeds ~ntaminants that may ar not be regulated Include errieria from Ta61e 1 that given poor (rather than dHFerent) quality water
stantlards in the future or wouW 6e at very low levels address SDWA secondary that meets drinking water shandards
on an infrequent basls standards and seleCed cri[eria Are tAe s[aff quality goals meY7
from Tables 48 5
~ualitative measure based on What are the number of acres oi wetlands
ProlecUOn or enhancement of land and total nat proJect impac[s to disturbad?
Have we enhanced the environment9
Maxknize environmental water habitats and resources and reducing ~tlands, reducing basin-witle
pollution lmpacFs through Have we eliminatad pollution or merely
enhancement exlsting and Tuture polluUon sources ellmina[ion of pollution sources or Passed the pollution on to others, including
d
th
f
l
if
~
_ basinwida reductions through best ens an
o
er users o
Bou
der Reservo
t
management prac[ices Can we maka the attemative carbon neutral or
reduce the prbon balance?
QualRative measure based on an
Maximize ecceptabil'ily by timiting evaluation of the oppostion to be Are we Impacting neighbors during
Maximize Acceptabilily dlsturbances end other impacts to expected irom state and lopl constructlon or operatlons?
neighbors, commuters, e[c. govemments and other Are commuters effected during consiruction?
Interested organizations
Boulder Reservoir Water Supply and Treatrnent Suggested
Obiectives
Objectlves Descilptbn Example Crkeria Notes ,
Do we need Larimer or Boulder County
permits7
Will Boulder County ptace limks on hours of
Need for 1041, 404 or other local, stata or Numher of permilling agenaes constructlon increasing consWCtion costs as
TlmelinesslEase of Permitfing federsl permils, ahility to deliver project by involved In approval happened wkh Longmont pipeline projedl
the time ihey are needed Is a 404 permit requl2d?
. ~ Howisprojedfeasibilityimpaded'rfother
participants drop out?
Nama:
Dete Complebd:
Boulder Reservoir Source Water and Water Treatment Plant
WeighBng Objectlves - Paired Comparison Worksheet
Wdghtlng: Use fha yrid befow to wrnpan ab,~ec8vas one 1o arroMer. For g~,&gx, ask Ne ques6on'NRJch o/these Iwo
oDlecNveslamostlmpaMntlome7' CirclefhemoallmpaleMa/thefwo(I.e.,drrJemyoneolNreMronum6orslnaechboz).
Attachedfa en example d e comp'eted loim showlnp Mw the wrveyshoWdlook when }rou fiM.sh (wRh wre tlrde in each ara o/
Ne aquere~.
~ Manage Costs
2 7AaximlzaWaterYleldendSystem
3 Simplify Operations
4 Ensure Meeting WaterQuelky Reguletions
5 ProvidaExceptionalTreatedWaterQuelity
that Ezceeds 9lendarda
6 MaxitnlzeEpvironmentalEnhencement
7 MaxlmlzeAccaptability
8 TImellnesslEsae of PermRtlng
Opdonal: Myau would fike b know ihe taaulta of your exe~clae,lotel the numEer of Umes earh obJecllve Is drded e~ aMer ihat
number in lAe corretpontlin8 b0x 6elqY. DMde hy 28 [o get en ap~~[vumale wag~Yn9.
• 2+
a ~* e ~a
,y~a a c° ° c° 'O m
~e o 3 ~q ~ a ~pa~ ~
c` ~
4 ~ O amm~~ ~,~mBmD c m
~ 3°~ ~a d aco' ~ `OO" p~p Y~ ~~
G d ~
,~,~ ~~a a y~C~ ~$ Sry~" Ar~c1' F Fm~
Sn $~ .C. a le~~ b~ C~A~S 4~IUC ~ A0~
5 4 2 4 3 4 2 4
8%
4%
%
494
1%
49G
% x~mwolnm~,arakd
~eenmm ~n.tTwi. ]q
P~~wnpY~ efN?I~~Nu
14% IDWltlenumbminmw~bove
b ~^I
Name:
Oate Completed:
Boulder Reservoir Source Water and Water Treatment Plant
Wetghting Objectives -- Paired Comparison Worksheet
WWghfln8~ Use fhe p~to' below to compa~e o6~ectlves orre to enolfrer. For p~(,¢g,y, ask Me ques6on'N9fkh ol Nrese Iwu
obJectlves fa mosflmpoAeM fo me?' GrW Ihe mosf tmportent ol fhe hvo Q.e., drele oNy one o{the hw numbers7n each boz).
Rttarhed7s arr exampk o!a wmpletedfam ahowilg how fhe aurvey sM1oWdknk whan you Anlah (wifh ane ortie (n aach one M
Me squaras).
•
~ Manage Costs '
~ 2 Maximfae Wetar Yleld and System Rellabilfty
2
3 SlmpGiy Operations
4 Ensure Meatlng Water Qua~Hy Regulattons
$ ProvldeExceptionalTreatedWaterQualFty
~IIHS E%C@BAE 5~811d8Id8
6 Merzimtze Environmantal Enhencement
7 MaximizeAcceptabflity
8 TImellnasslEese oi Permilting
Optlonal: M you woNtl Ilke to laaw 1he res~d~s d Y W~ ~~%e, tolal Ne numher of timas aech ob}xtWe In drtied entl eriter Ihel
number in lhe mrtespond~n9 ~~~'• DivlOe by 28 to gel an approximsk weigMinB.
vm.a
. m~
A~wM~
rox~bws
~
~ BRWIFwmPN~bIwN6MIMfamab~Blenko4~veeWOhN~~1 /HLZOGi
' ResuNs otMis welghtlng exe~cise wtll 6e compiled and usetl to nnk the akematives
~~7-ffiC/f/YIt-~L~7- -~
~ Southern Water Supply Project II
Feasibility Study
r~~a ror
j. Northern Colorado Water Conservancy District
220 Water Avenue
i Berthoud, Colorado 80513
Prepazed by
Integra Engineering
450 Decahu Street
~ Denver, CO 80204
In association with
~ CH2M Hill
Lyman Henn
January 6, 2006
Table of Contents
Section 1- Introduction ................................................ l-1
1.1 Soathern Water Supply Project II ..........................................1-1
1.2 Project Background ..................................................................1-1
1.3 Study Objectives and Methodology .........................................1-1
1.4 Report Organization .................................................................1-2
Section 2- Project Participants ................................... 2-1
2.1 City of Boulder ..........................................................................2-1
2.1.1 Delivery Point ....................................................................2-1
2.1.2 Flow Rate ...........................................................................2-1
2.1.3 Hydraulic Pazameters .........................................................2-1
2.2 Town of Erie ..............................................................................2-2
2.2.1 DeliveryPoini ...............................................
2.2.2 Flow Rate ......................................................
~ 2.2.3 Hydnulic Pazameters .........................................................2-2
2.3 Left Hand Water District .........................................................2-2
2.3.1 DeliveryPoint ..................................................•---~--...........2-3
232 Flow Rate ...........................................................................2-3
2.3.3 Hydraulic Pazameters .........................................................2-3
2.4 Eastern Turn-out ......................................................................2-3
2.5 Snmmary of Project Participants ............................................2-3
Section 3 - Information/Data Resources .....................3-1
3.1 Data from Original SWSP ........................................................3-1
3.1.1 SWSP - St. Vrain Supply Canal Modifications ................3-1
3.12 SWSP-BroomfieldPipeline ............................................3-1
3.2 Project Mapping and Topograp6y ..........................................3-3
3.2.1 Aerial Photography and Topographic Data ......................3-3
3.3 GIS Information ........................................................................3-3
33.1 Boulder County ................................................. ................3-4
332 Larimer County .............. ............................... ................3-4
333 City of Longmont .............................................. ... ~ ......3-4
33.4 Colorado Natural Heritage Program ................. ................3-5
3.4 Municipalities ....................................................................•••.....3-5
3.4.1 City of Longmont ..............................................................3-5
3.5 Geologic Mapping and Data ....................................................3-6
3.6 Utilities and Infrastructure ......................................................3-6
3.7 EnvironmentaUCultural Assessments .....................................3-6
Section 4- St. Vrain Supply Canal Diversion Structure
Hydraulic Analysis ............................................. 4-1
4.1 Existing Diversion Strncture Information ..........................................41
4.2 Hydraulic Analysis ................................................................................42
4.2.1 Putpose/Methodology ..............................................................4-2
4.2.2 Hydrdulic Criteria/Assumptions ..............................................4-3
j 4.23 Field Measurement Confirmation ............................................4-5
, 4.2.4 Loss Calculations .....................................................................45
42.5 Conclusion ...............................................................................4-9
4.3 Connection to E~sting SWSP Facilities .............................................49
Section 5- Pipeline Hydraulic Criteria and Materials....... 5-1
5.1 Pipeline Hydraulic Criteria ...............................»..... ..................:.........5-1
5.1.1 Operating Pressures ..................................... ............................5-1
5.1.2 Pipeline Sizing ............................................. ............................5-1
5.2 Pipetine Material ...................................................................................5-3
5.2. t Steel Pipe ..................................................... ............................5-3
5.2.2 Ducrile Iron Pipe .................................•-~-----. ............................5-4
5.2.3 Material Comparison ................................... ............................5-4
Section 6- Pipeline Alignment Evaluation Methodology and
Criteria ................................................................ 6-1
6.1 Pipeline Route Evaluation Methodology Outline ..............................6-i
6.1.1 Determination of Participant Requirexnents .................. ...........6-1
6.1.2 Develop Preliminary Feasible Pipeline Alignments ..... ...........6-1
6.13 Select Complete Altemative Pipeline Alignments ....... ...........6-1
6.1.4 Select Preferred Pipeline Alignment ............................. ...........6-1
6.1.5 Prepaze Final Project Cost Estimate ............................. ...........6-2
6.2 Qualitative Evaluation Criteria ...........................................................6-2
6.2.1 LandUse ....................................................................... ...........6-2
6.2.2 Water Resources ........................................................... ...........6-4
6.23 Visual Resources .......................................~--......--- ~ -... ...........6-5
6.2.4 Transportarion Impacts ................................................. ...........6-6
6.2.5 Biological Resources .................................................... ...........6-6
6.2.6 Cultural Resources ........................................................ ...........6-8
6.2.7 GeotechnicaUGeologic .................................................. ...........6-9
6.2.8 Permitting ...................................................................... ...........6-]0
6.3 Quaotitative Evaluation Criteria .............................................. ...........6-10
Section 7- Development of Pipeline Route Alternatives.... 7-1
7.1 Development of Preliminary Feasible Pipeline Alignments ..............7-]
7.1.1 Areas For Alignment Altematives Analysis .............................7-1
7.1.2 PreliminaryAlignments/AlignmentSegments ........................7-1
7.2 Selection of Complete Pipeline Alignment Alternatives ....................7-2
7.3 Pipeline Alignmeut Alternatives Descriptions ...................................7-2
7.3.1 Northem Reach ........................................................................7-2
7.3.2 Southwest Reach ......................................................................7-4
Section 8- Preferred Pipeline Route Selection .................... 8-1
8.1 System Hydraulics ................................................................................&1
8.2 Interference Analysis ............................................................................8-2
8.2.1 Southwest Reach Utility Interference Analysis .......................8-3
8.2.2 Larimer County Road 8E Utility Interference Analysis ..........8-7
8.3 Easement Reqnirements .......................................................................&8
83.1 Permaneni Easement ...................................................... ..........8-8
8.3.2 TemporaryEasement .....................'...--•~---.................... ..........8-8
83.3 Typical Pipeline Consh-uction Corridors ....................... ..........8-9
8.4 Quantative Analysis ..............................................................................&10
8.5 QaatitativeAna(ysis ..............................................................................&il
8.6 Selection of Preferred Pipeline Alignment .........................................8-11
8.6.1 Erie Participating ..............................•----........................ ..........8-11
8.6.2 Erie Not Par[icipating .................................................... ..........8-12
Section 9- Pipeline Operational Analysis ............................ 9-1
9.1 Basic Operation .....................................................................................9-1
9.2 Shutdowns....-•••• .....................................................................................9-1
93 Turnouts .................................................................................................9-1
9.4 ValvingReqnirements ..........................................................................9-2
9_5 System Control ......................................................................................9-2
Section 10 - Final Project Cost Estimates ............................10-1
10.1 PipelineInstallation ............................................................................10-1
10.2 St. Vrain Canal Diversion Structure Connection ............................10-1
10.3 Main Line Metering Facilities .............................................••••••.........10.1
10.4 Participant Turo-out Facilities ..........................................................10-2
10.5 Pipeline Inter-ties and Main Line Isolation Valves .........................10-2
10.6 Permanent and Temporary Easements ............................................10.2
10.7 Other Costs............•-••• ................••••••••.................................................10-2
10.8 Reimbursement Costs .................._........................_............................10-3
10.9 Total Project Costs......•••• ........................•••......................••••••••...........10-3
] 0.10 Project Participant Costs ...............•••••.................._•••••••-••••••...........10-3
Appendix
Section 3: Colorado Natural Heritage Prograzn Report
Cultural Resources Assessment Report
Section 6: Boulder County 1041 Regulations
Section 8: Hydraulic Analyses
Hydraulic Profiles
Altemarive Preliminary Cost Estimates
Section 10: Pipeline Appurtenance and Facility Cost Estimates
Total Project Cost Fstimates
List of Tables
Table 2-1 Project Par[icipant Demands/Delivery Point HGL's ................................2-4
Table 41 Diversion Struchue Data ..........................................................................4-1
Table 4-2 Diversion Shucture Components/Headloss Equations .............................4-4
Table 43 Vortex Suppression Submergence Requirement Equations .....................4-5
Table 44 Comparison of Calculated vs. Measured Headlosses ...............................4-5
Table 45 Total Calculated Headlosses .....................................................................4-6
Table 46 Required and Available Submergence Depths .........................................4-7
Table 5-1 Calculated Fricrion Slopes (42-inch Pipe @ 57.4 cfs) .............................5-2
Table 5-2 Pipeline Sizing/Hydraulic Criteria ...........................................................5-2
Table 6-I Pipeline Installation Unit Costs ................................................................6-12
Table 6-2 Pipeline Installation Additive Item Unit Costs .........................................6-13
Table 8-1 System Design Pazameters .......................................................................8-1
Table 8-2 Pipe Summary ..........................................................................................8-2
Table 8-3 Utility Locates and Information - Southwest Reach ................................8-4
Table 8-4 Utility Locates and Informarion - Northern Reach ..................................8-7
Table 8-5 New Pem~anent Basement Acquisition Length Comparison ...................8-8
Table 8-6 Total Temporary Easement Length Comparison .....................................8-9
Table 8-7 Preliminary Estimated Pipeline Construction Costs .................................8-11
Table 10-1 Total Estunated Project Costs ................................................................10-3
Table 10-2 Estimated SWSP II Project Participant Costs ........................................10-4
Appendix
Table 8A-1 SWSP II Hydraulic Analysis - Altemative I ................................ ...........Section 8
Table SA-2 SWSP II Hydraulic Analysis - Altemative 2 ................................ ...........Section 8
Table 8A-3 SWSP II Hydraulic Analysis - Altemative 3 ................................ ...........Section 8
Table 8A-4 SWSP II Hydraulic Analysis - Alternative 4 ................................ ...........Section 8
Table 8A-5 SWSP II- Altemative 1 Preliminary Cost Estimate ..................... ...........Secrion 8
Table 8A-6 SWSP II- Altemative 2 Preliminary Cost Estimate ..................... ...........Section 8
Table 8A-7 SWSP II- Altemative 3 Preliminacy Cost Estvnate ..................... ...........Section 8
Table 8A-8 SWSP II- Altemative 4 Preliminazy Cost Estimate ..................... ...........Section 8
Table 10A-1 St. Vrain Canal Diversion Structure Connection Cost Estimate.........Section 10
Table 10A-2 Main Line Metering Facility Cost Estimate ....................................... .Section 10
Table 10A-3 Left Hand Water District Tum-out Facility Cost Estimate ................ .Section 10
Table 10A-4 Town ofErie Turn-out Facility Cost Estimate ................................... .Section 10
Table 10A-5 City of Boulder Tum-out Facility Cost Estimate ............................... .Section 10
Table 10A-6 Pipeline Inter-tie Facility Cost Estimate ............................................. .Section 10
Table 10A-7 Main Line Isolation Valve Facility Cost Esrimate ............................. .5ection 10
Table 10A-8 Erio-participating Altemative - Final Cost Estimate ..........................Section 10
Table 10A-9 Erio-not pazticipating Alternative - Final Cost Estimate ....................Section 10
Table 10A-10 Erie-participatingAltemative-Non-specific CostAllocation.........Section 10
Table 10A-11 Erie-not participating Aitemative -Non-specific Cost Allocation...Section 10
Table 10A-12 Erie-pazticipating Altemative - Final Project Participant Costs.......Section 10
Table 10A-13 Erie-not pazticipating Altemarive - Final Project Participant Costs.Section 10
List of Figures
, Fouo~~
. Figure 1-1 NCWCD East Slope Distriburion System ...............................................1-1
~ Figure 2-1 SWSP II Project Participant Locations ...................................................2-3
Figure 3-t City of Longmont Boundary ..................................................................3-S
~ Figure 3-2 City of Longmont Clover Basin Pipeline Alignment .............................3-6
Figure 4-1 Existing Diversion Structure ...................................................................4-3
Figure 42 Total Calculated Headlosses ...................................................................4-6
` Figure 43 Required and Available Slide Gate Submergence WSEL's ...................4-8
Figure 4-4 Required and Available 72-inch Inlet Pipe Submergence WSBL's........4-8
Figure 7-1 Selected Pipeline Alignment Altematives
..7-2
Figure 8-1 (A-C) Typical Construction Comdors - Pazallel Alignment ..................8-9
Figure 8-2 Typical Construction Corridor- New Easement ....................................8-9
Figure 8-3 Typical Construction Corridor- 50 foot width .......................................8-9
Figure 8-4 Pipeline Installation Cost Curve ..............................................................8-10
Figure 8-5 Qualitative Analysis ................................................................................8-11
Figure 8-6 Prefeaed Pipeline Alignment ..................................................................8-12
Appendix
Figure 8A-1 Hydraulic Profile - Alternative 1 ............................................................Section 8
Figure SA-2 Hydraulic Profile - Altemative 2 ............................................................Section 8
Figure 8A-3 Hydraulic Pmfile - Altemative 3 ............................................................Section 8
Figure 8A-4 Hydraulic Profile - Altemative 4 ............................................................Section 8
~ --
I Section 1 - Introduction
1.1 Southern Water Supply Project II
The Southern Water Supply Project (SWSP) II is a coIlaborative project between six (fi)
water providers (participants) and the Northern Colorado Water Conservancy District
(District) to provide a mechanism to convey Windy Gap and Colorado-Big Thompson
(C-BT) water from Carter Lake to each of the individual participants. Each of the six (6)
project participants is located in the northern Colorado front range within the Northem
Colorado Water Conservancy District and Municipal Subdistrict boundaries. Figure 1-1
is a map showing the DistricYs East Slope Distribution System, including the originaI
SWSP facilities. The SWSP II project involves constructing a second buried
transmission pipeline south from the St. Vrain Supply Canal diversion structure at Carter
Lake to the individual participant delivery points.
1.2 Project Background
In 1993, the original Southern Water Supply Project pipeline (Carter Lake to Broomfield
Pipeline) was constructed from the St_ Vrain Supply Canal diversion structure at Carter
Lake south to its terminus at the City of Broomfield's then new water treatment plant and
storage reservoir located northeast of the intersection of Sheridan Boulevard and 144`n
Avenue, a length of approximately 33.5 miles. The original project was a collaborative
effort between twelve (12) project participants and the District to convey Windy Gap and
C-BT water from Carter Lake to each participant delivery point. Since the construction
of the original pipeline, the District has consvucted two booster pumping stations along
the existing pipeline to increase flow rates as a result of additional water deliveries
requested by the original project participants, effectively utilizing the capacity of the
original pipeline.
Due to the interest shown by vaxious water providers within the District and Municipal
Subdistrict boundaries to construct a second pipeline, the District and the project
participants (consisting of some of the original project participants and of new
participants) have vndertaken this SWSP II feasibility study to determine a preferred
pipeline route and the estimated cost of construction.
1.3 Study Objectives and Met6odotogy
The objective of this feasibility study is to determine a preferred pipeline route to deliver
the required flows to each participant delivery point and provide an accurate estimate of
the construction costs to enable the project participants to determine their levei of
participation in the project.
This study will initially determine each participant's specific delivery point location. the
required hydraulic grade line at the delivery point, and the participant's required deli~~ery
flow rate. Once these project objectives are defined, preliminary feasible pipeline routes
will be developed from a review and analysis of multiple sources of applicable data ( i.e.,
Fina! Re~ort
SWSP II Pf•ojc>ct FE>crsihilrtti~ Sruch Pr~;c~ 1-!
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aerial photogaphy, GIS data, geologic data, property information, existing utility
information, as well as environmental, cultural, and permitting infonnation). The
feasible pipeline routes will then be evaluated based on both qualitative (non-economic)
and quanritarive (economic) screening criteria formulated in tlus study. The necessary
hydraulic criteria development and analysis will be performed to determine pipeline
diameters, wall thiclmesses, and pipeline appurtenance requirements. The preliminary
feasible pipeline routes will be screened and complete alternative aligmnents will be
selected.
Once complete alternative alignments aze selected, the hydraulics will be re-analyzed to
refine pipe diameters and wall thiclmesses, and an existing utility interference analysis
performed. The selected preliminary aliguments will be re-evaluated based on the
applicable qualitative criteria and more detailed cost estimates for each preliminary
aligtunent. Based on the evaluation ofthe selected preliminary alignments, a preferred
pipeline alignment will be determined.
Additionally, operational issues will be discussed for the preferred pipeline aligrunent In
conclusion, a final detailed construction cost estimate foi the project will be performed.
1.4 Report OrganizaNon
1'his SWSP II Feasibility Study report sequentially documents the study process from the
definition of the participant requirements to the selection of a preferred pipeline
alignment and completion of a final project cost estimate. The report is organized as
follows:
• Section 1 provides an introduction to the project, background information on the
original SWSP pmject, and presentation of the study objectives.
• Section 2 identifies the pmject participants and defines each pazticipanYs specific
requirements conceming delivery point location, delivery point hydraulic grade,
and required delivery flow rates.
• Section 3 identifies and describes the multiple sources of information and data
utilized in Uus study to develop altemative pipeline routes and perform the route
evaluations and analysis.
• Section 4 details the hydraulic analysis performed on the existing St. Vrain
Supply Canal diversion structure and the altemative connection options at the
existing diversion shucture.
• Section 5 outlines the development of the pipeline hydraulic criteria utilized in
this study, as well as the determination of pipeline material.
• Section 6 describes the pipeline route analysis and evaluation methodology and
develops the qual~tative and quantitative criteria utilized in this study.
f in~d Report
.S'[~G:S'P ll Project Feusihrl~h .S)udr Puge !-Z
• Section 7 documents the selection of the preliminary altemative alignments and
provides a detailed description of these alternatives.
• Section 8 documents the evaluation and analyses for the selecrion of a preferred
pipeline alignment.
• Section 9 provides a discussion of the proposed pipeline operations (based on the
preferred pipeline alignment), specifically where inter-ties with the existing
pipeline are proposed to be located and the necessary pipeline appurtenances to
achieve the desired operational flexibility.
• Section 10 documents the development of the final detailed cost estimate and the
cost allocation for each individual participant, based on the preferred pipeline
alignment.
Final Report
SRSP II Proje~v Frusih~lrtr Stardti~ Prr~e l-3
Section 2 - Project Participants
The stated objective of the SWSP II is to provide for deliveries of Windy Gap and C-BT
water from the existing diversion structure on the St. Vrain Supply Canal at Carter Lake
to each of the pmject pazricipanYs individual delivery points. The total required flow
from the diversion structure on the St. Vrain Supply Canal for the six (6) current project
participants is 75 cubic feet per second (cfs). This section identifies each of the six
project participants and their specific delivery point locations, required delivery hydraulic
grade line (HGL), and required flow rate.
2.1 City of Boulder
Discussions for the City of Boulder delivery point, required flow rate, and hydraulic
parameters were held with Cazo1 Ellinghouse, Coordinator of Water Resources for the
City of Boulder during the execution of this study. The consh-uction of the SWSP II
would allow the City of Boulder to convey their existing water deliveries through the
proposed pipeline instead of the current conveyance tluough the open channels of the St.
Vrain Supply Canal and the Boulder Feeder Canal. Delivery of the water Uuough the
pipeline is much preferred due to the better water quality and the abiliTy to receive water
throughout the entire yeaz. The water quality currendy is degraded due to the numerous
contamination issues associated with conveyance in open channels. In addition, water
deliveries can currently only be received during the normal irrigation season of April I
thtough October 31.
2.1.1 Delivery Point
The City of Boulder's delivery point is anticipated to be at their existing Boulder
Reservoir Water Treatrnent Plant (WTP) facility, located east of Boulder Reservoir, neaz
the intersection of Highway 119 and N. 63`d Street. The City of Boulder desires a direct
feed into their treatment facility and has indicated that the connection point would be
located at the raw water intake piping to the facility. The City of Boulder does not
anticipate delivery of SWSP II water into Boulder Reservoir. The location of the City of
Boulder's individual hun-out facilities will depend upon the selected alignment of the
proposed pipeline.
2.1.2 Flow Rate
The City of Boulder is anticipating a maximum flow rate of 25 cfs &om the SWSP II
pipeline.
2.13 Hydraulic Pazameters
To deliver water to the Boulder Reservoir WTP, the SWSP II pipeline must be capable of
providing an HGL elevation of 5200 feet at the plant site. This HGL is based on the
hydraulic profile depicted in the Boulder Reservoir WTP Improvements 2003 plan set
and has been ~eritied by the City.
Frnal Report
.SWSP I/ Pro~err FeasihrliN S'tuclr Page '-l
2.2 Town of Erie
Discussions for the Town of Erie delivery point, required flow rate, and hydraulic
parameters were held with Gary Behlen, Town of Erie Public Works D'uector during We
execution of this study. Additional information was provided by Baird Yang of Bums &
McDonnell based on their current work for the expansion of the Town of Erie Lynn R.
Morgan (WTP). The conshuction of the SWSP II would allow the Town of Erie to
convey their existing water deliveries through the proposed pipeline instead of an
alternate conveyance through the open channels of the St. Vrain Supply Canal, Boulder
Feeder Canal, Boulder Supply Canal, and currently proposed Town of Erie pipeline.
Delivery of the water through the SWSP II pipeline would provide better water quality
and the ability to receive water throughout the entire yeaz. The water quality received
through the alternate facilities is degraded due to the numerous contamination issues
associated with conveyance in open channels. In addition, water deliveries through the
altemate facilities could only be received during the normal irrigation season of April 1
thmugh October 31.
2.2.1 Delivery Point
The Town of Fsie's prefened delivery point would be at the existing Lynn R. Morgan
Water Treatment Plant, located just west of N. 119'~ Street, north of Arapahoe Road.
However, Bums & McDonnell indicated that other possible delivery locations could
include Erie Lake or Prince Reservoir. The tum-out facility's locarion from the proposed
SWSP II pipeline is anticipated to be near their existing tum-out from the existing SWSP
pipeline, but will ultimately depend upon the final alignment of the proposed pipeline.
2.2.2 Flow Rate
The Town of Erie is anticipating a ma~cimum flow rate of 20 cfs from the pmposed
SWSP II pipeline project.
2.23 Hydraulic Pazameters
Based on the information provided by Bums & McDonnell, the required hydraulic gade
at the delivery point at the Lynn R. Morgan WTP would be approximate elevation 5280,
which corresponds to the level of their raw water equalization tank. The HGL's at Erie
Lake and Prince Reservoir aze elevation 5229 and elevation 5256, respectively.
2.3 Left Hand Water District
Discussions for the Left Hand Water District (LHWD) deliverv point, required tlow rate.
and hydraulic parameters were held with Hank Schmidt, Trea[ment Plant Manager and
Chris Smith. Project Engineer durin~ the execution of this study. The construction of the
SWSP II would allow the LHWD to come~ their existing C-BT water deliveries (and
additional o~ned shares of C-BT «ater ti+r ~~hich there are no current conveyancc
~
i
~- ,
Final Reprn r
SWSP I/ Pruirr~ Frasrhilih' Sn+dr Page _'-'
facilities) through the proposed pipeline instead of the existing conveyance facilities
which include the open channels of the St. Vrain Supply Canal and the Boulder Feeder
Canal. Delivery of the water thmugh the pipeline is much preferred due to the better
water quality and the ability to receive water thmughout the entire yeaz. The water
quality currently received is degraded due to the numerous contamination issues
assceiated with conveyance in open channels. In addition, water deliveries can cutrently
only be received during the nortnal irrigation season of April 1 through October 31.
2.3.1 Delivery Point
The LHWD's delivery point is anticipated to be at their existing Dodd Water Treatment
Piant facility, located at 6800 Nimbus Road, west of Niwot, Colorado. LHWD's
connection point at the Dodd WTP would be located just downstream of their existing
, raw water vault on an existing 20-inch pipeline. The location of LHWD's tum-out from
i the proposed pipeline will depend upon the final alignment of the proposed pipeline.
23.2 Flow Rate
The LHWD is anticipating a flow rate of 11 cfs from the SWSP II pipeline.
': 2.33 Hydraulic Pazameters
To deliver water to the Dodd Water Treatment Plant, the LHWD requires an HGL at
approximate elevation 5130 at the plant site.
2.4 Eastem Turn-Out
The eastem tum-out would serve the remaining three participants, Little Thompson
Water District, Central Weld County Water District, and the Town of Frederick. It is
anricipated that these participants will be served from a common tum-out with a capacity
of 19 cfs near the Ft. Lupton tum-out from the existing SWSP Bmomfield pipeline just
east of N. 95`h Street and Vermillion Road. This tum-out is assumed to feed a branch
pipeline that will supply a future regional water treatrnent p]ant or individual facilities.
The assumed minimum HGL at this tum-out is elevation 5400.
2.5 Summary of Project Participants
Figure 2-1 is an aerial photograph of the project area identifying each project
participant's delivery location, flow, and required delivery hydraulic grade. Ntigure 2-1
also shows the location of the existing SWSP Broomfield pipeline in relation to the
SWSP [I participant's delivery locations.
Table 2-1 provides a summary of the current project participants anticipated demands
and required delivery point hydrautic grade lines.
Final Repon
SWSP // /'i-o/ect Feu.ubtliry Studi PuKc' _'-3
Table 2-1. Proiect Particioant Demands/Delivery Point HGL's
Partici ant Demand/HGL
City oBoulder ,
Demand, cfs 25
De]ivery Point HGL, El. 5200
Town of Erie
Demand, cfs 20
Delivery Point HGL, El. 5280
Lett Hand Water District
Demand, cfs 11
Delivery Point HGL, El. 5130
Little Thompson Water District
Demand, cfs 3
Delivery Point HGL, EI. 5400
Central Weld County Water District
Decnand, cfs 10
Delivery Point HGL, EI. 5400
Town of Frederick
Demand, cfs 6
Delivery Point HGL, El. 5400
Total Demands, c(s 75
Flna! Xeport
SWSP I! Proic ~ r Feas~bilin Sr,rdi Pu~e Z-4