HomeMy WebLinkAbout4 - Final recommendation of CEAP for Betasso WTP Pipeline ProjectsCITYOFBOIILDER
WATER RESOURCES ADVISORY BOARD
AGENDAITEM
MEETING DATE: November 20, 2006
AGENDA TITLE: Recommendation to the City Council on the Community and
Environmental Assessment Process (CEAP) Review for Orodell Pipeline / Betasso
Pipeline / Discharge Pipeline Project
PRESENTER/S: Bob Harberg, Utilities Project Management Coordinator
Carol Ellinghouse, Water Resources Coordinator
Joe Taddeucci, Utilities Project Manager
EXECUTIVE SUMMARY:
City staff proposes to replace portions of two critical, aging pipelines that provide water
deliveries to and from the Betasso Water Treatment Plant (WTP). This action will
improve the reliability of the City's municipal water supply system. A review of options
for accomplishing the upgrades revealed a unique opporiunity to alter the functions and
configuration of existing pipelines and achieve cost savings through reuse of the existing
facilities. In addition, this approach has the potential to address water quality probiems
experienced during hydroelectric plant capacity tests. Adopting this project approach
could also provide the means to offset the costs of the project by increasing hydropower
revenues over time. Existing and proposed facilities are shown in Attachment A.
The Community and Environmental Assessment Process (CEAP) evaluation for the
proposed Orodell Pipeline/ Betasso Pipeline/ Raw Water Discharge Pipeline Project is
attached (Attachment B). Staff is requesting WRAB approval of the CEAP and the
Altemative 2 be constructed.
A draft CEAP was presented to the WRAB during its August 2006 meeting. Based on
the discussion and comments that occurred during that meeting, as we11 as review by the
CEAP Review Group and addition of new information, a few revisions have been made
in preparation of the final CEAP as follows:
Continuous diversion of flows through Lakewood Pipeline solely for
hydroelectric generation and discharge back to Boulder Creek has been eliminated
from the final CEAP. It would be possible to divert water from North Boulder
Creek at Lakewood Reservoir that is in excess of the City's municipal water
needs from this source and then discharge the water back to Boulder Creek
through the proposed discharge pipeline for purposes of increasing hydroelectric
AGENDA iTEM # PAGE
generation at Lakewood Hydro. The amount of extra water that could be diverted
would be limited both by the City's contractual commitments to the Colorado
Water Conservation Board to provide instream flows below Lakewood Reservoir
and by the availability of any capacity in Lakewood Pipeline in excess of
municipal water needs. The possibility of diverting this extra water is an
operational decision that can be made at any time without capital improvements
and is not a part of the proposed action. The economics that are presented in this
document do not include any revenues from power generated through use of extra
water delivered at Lakewood Reservoir The draft LEAP presented in August
included such diversions.
• Project costs have been updated to 2007 dollars.
• Existing hydroelectric plants have been assumed to generate revenue for the full
50 years of the analysis. Previously the plants were assumed to stop generating
once they reach 50 years in age, which in some cases would occur prior to the end
of the 50-year analysis period. Based on experience, the cost of refurbishment for
aging hydro plants is offset by increased efficiency resulting from the
refurbishment. This financial "wash" is reflected in the analysis by not including
any additional costs or revenue associated with a refurbishment.
Orodell Pipeline
Orodell Pipeline carves treated water from the Betasso WTP to the Orodell Hydroelectric
Plant and the City's treated water transmission pipeline in Boulder Canyon. Orodell
Pipeline, constructed in the 1950s and 1960s, is a steel pipeline with exterior coal tar
enamel coating which varies in diameter from 18 to 24 inches. Orodell Hydro Plant was
added to this pipeline in 1987. The lower portion of this pipeline, located adjacent to
Boulder Creek, has required repairs in recent years due to significant corrosion and is
scheduled for complete replacement. Internal and external assessments of the upland
portion of Orodell Pipeline showed the condition of this part of the pipeline to be good
enough to operate until its replacement, probably within the next 15 years.
Proposed Discharge Pipeline
As investigation of the Orodell Pipeline was underway, discussions were taking place
about ways to alleviate water quality concems at Betasso WTP during hydro plant
capacity tests. One possible solution is providing a discharge pipeline from Betasso WTP
to Boulder Creek to dispose of excess water from the tests.
Monthly hydro capacity tests are required under a power sale contract with Xcel Energy
that includes three hydroelectric facilities-Betasso Hydro, Lakewood Hydro and Silver
Lake Hydro. The capacity payments provide considerable revenue to the city. The
contract requires operating all three plants at the same time. Flows to Betasso WTP
during the capacity tests are regulated to produce the best possible calculation of a
formula in the contract to maximize capacity payments while maintaining treated water
quality. In some months, flows cannot be adjusted sufficiently to produce the maximum
possible payment from Xcel because of water quality concerns.
AGENDA ITEM # PAGE
Capacity test flows through the hydro plants and into Betasso WTP almost always exceed
the demand for treated water. Flows must be increased over several hours with both the
Lakewood Pipeline and the Betasso Pipeline carrying much more water than usual.
These rapid flow changes can cause disruptions to the treatment process and a decline in
treated water quality. Also, all raw water delivered to Betasso WTP must be treated and
released into the treated water delivery system since there is no means to discharge
excess water elsewhere. Water quality problems in the treated water distribution system
can result from introduction of a large volume of treated water during generation capacity
testing.
Betasso Pipeline
The city's goal for Betasso WTP capacity requires a delivery capacity of 30 million
gallons per day (mgd) from the Barker system. At present, Betasso Pipeline can only
supply 30 mgd if water in the pipe reaches a velocity that is damaging to the interior
cement mortar lining and if hydroelectric generation at Betasso Hydro is sacrificed. High
pipeline velocity in the Betasso Pipeline results from both the small diameter of the
pipeline (20 inches) and friction caused by the uneven surface of the lining. If
recommended flow velocities are maintained (less than 8 feet/second) and if power
generation at Betasso Hydro is preserved, the existing Betasso Pipeline has a maximum
delivery rate of about 22.6 mgd.
The Betasso Hydro rated capacity is 3.2 megawatts. Due to the constraints in Betasso
Pipeline, the plant can only achieve about 2.4 megawatts production. If a larger diameter
pipeline with a smoother interior replaced the existing Betasso Pipeline, the design
capacity of Betasso Hydro would be achieved and more generation of nonpolluting,
renewable hydroelectricity could occur. This change would increase Betasso Hydro
generation by about 51,500 megawatt-hours of electricity over the life of the facility.
Internal and external inspections of this pipeline determined that its condition is currently
good. At the current time, it does not appear that the advanced age of this pipeline
(nearing 50 years) warrants its replacement, even though size and head loss factors might
justify rebuilding the pipeline.
Fiscal Impacts•
Budgetary: Funding sufficient to complete the project is available in the Capital
Improvement Program for 2006-2007 using money budgeted for repairs to Barker
system pipelines and replacement of the Orodell Pipeline. The preferred
alternative would cost $3.3 million to construct. The increased present worth of
power sales revenues over the life of the existing hydro facilities is $4.5 million.
Staff Time: Project staff time would be a part of the normal work plan.
Other Imaacts:
Environmental The preferred alternative would increase hydroelectric
generation by 51,500 megawatt-hours over the life of the hydro plants. The
increased generation would displace the burning of approximately 26,500 tons of
coal for producing an equivalent amount of electric generation at a coal-fired
plant.
AGENDA ITEM # PAGE
Economic: Expenditures of water utility capital funds will be required now to
construct the project, and hydro revenue increases to offset the expense will come
in over a period of 15 to 20 years from now. Use of these capital funds for this
project precludes their use for other capital needs for many years.
Community: It is anticipated that a Boulder County 1041 Review will be
required for the project.
Other Board and Commission feedback and public feedback: Standard CEAP review
processes have been followed, including review and comment by the City's
internal LEAP review group. The CEAP review group agreed with the impact
assessment and preferred alternative and recommended that the CEAP was ready
for boazd review on September 18, 2006. An initial presentation and project
introduction was made to the WRAB in August 2006, which was the first
opportunity for public comment on this project. No public comments were made
during the August WRAB meeting on the CEAP proposal. A public hearing for
this project will occur during the November 2006 WRAB meeting.
Staff recommendation: Staff recommends the WRAB approve the CEAP document
and that Alternative 2 be constructed.
Analysis:
Project alternatives
It is assumed for all alternatives that the lower portion of the Orodell Pipeline will be
replaced as planned. The attached CEAP discusses three project alternatives:
Alternative 1- (Status Quo) -Continue using existing facilities until
replacement is required for continuing operation.
Alternative 2 -Replace Betasso Pipeline. Reuse the existing Betasso Pipeline to
replace the majority of the Orodell Pipeline. Reuse the existing Orodell Pipeline
as a discharge line to return excess hydroelectric generation flows at Betasso
WTP to Boulder Creek.
Alternative 3 -Replace Betasso Pipeline. Reuse the existing Betasso Pipeline as
a discharge line to return excess hydroelectric generation flows to Boulder Creek.
Staff prefers Alternative 2 because it meets the identified purposes and needs of the
project while maximizing the reuse of existing materials. Replacement of the Betasso
Pipeline would provide an anticipated life for the pipeline of at least 50 years. Alternative
1 would not increase reliability of water delivery to Betasso WTP, address water quality
concerns with hydro capacity tests, or result in additional hydropower production or
revenues. Alternative 3 requires the existing Orodell Pipeline to continue to operate in a
demanding, high-pressure mode for the next 10-1 S years, after which time it would be
replaced.
Preferred Alternative
Several benefits for the municipal water supply system can be gained by altering the
functions of the existing Betasso Pipeline and the Orodell Pipeline at the same time as
AGENDA ITEM # PAGE
constructing a new Betasso Pipeline. Alternative 2 reuses both existing pipelines for less
demanding uses, thereby reducing long-term capital needs. This alternative:
• Allows delivery of up to 30 mgd from the Barker system to Betasso WTP and
improves redundancy and reliability of the city's raw water system.
• Reuses the existing Betasso Pipeline for Orodell Pipeline. This less
demanding (lower pressure) use would extend the -ife of the reused pipe and
delay capital expenditure for the eventual replacement of Orodell Pipeline
while increasing the reliability of the treated water system now.
• Reuse of the existing Orodell Pipeline as a discharge line from Betasso and
Lakewood Hydro Plants to Boulder Creek is a suitably undemanding use
given the condition of the pipeline and would alleviate water quality problems
associated with contractually-required monthly hydroelectric generation
capacity tests.
• Anew Betasso Pipeline would allow Betasso Hydro to achieve its design
generation capacity of 3.2 megawatts (MW) and would increase revenue to
the water utility under the existing power sales agreement with Xcel Energy.
This project is both environmentally and economically beneficial Total construction cost
for the preferred alternative for this project is $3.3 million. The present worth of
increased generation and capacity revenues is $4.5 million. The project has an estimated
payback period of 15-20 years.
Pur ose/Need Alternative 7 Alternative 2 Alternative 3
Re wires no ca ital ex enditures `~
Increases reliabili of Betasso Penstock / /
Increases reliabilit of Orodell Pi eline `~
Recycles existing Orodell Pipeline to extend its
usefulness to the ci /
Recycles existing Betasso Penstock to extend its
usefulness [o the ci / /
Increases capacity to deliver Barker system water to
Betasso WTP to 30 m d / /
Achieves intended capacity of Betasso Hydro (3.2
M / /
Mitigates potential treated water quality problems
associated with h dro ca acit testin
/
/
Increases renewable energy production using
existin h droelectric facilities / /
Increases h droelectric ca aci test revenues / /
Avoids temporary disturbance of a visible hillside
corridor /
Opportunity to improve appearance and quality of
ve elation in reviousl disturbed area
/
/
Allows existing facilities to remain in use for the
ma'ori of construction / /
Construction cost $0 $3.3 million $3.5 million
Present worth of increased generation and capacity
revenues $0 $4.5 million $4.5 million
Net Present Value $0 $1.2 million $1.0 million
Attachments:
AGENDA ITEM # PAGE
Attachment A: Existing and Proposed Facilities
Attachment B: Draft Community and Environmental Assessment Process (LEAP)
Review for Orodell Pipeline / Betasso Pipeline /Discharge Pipeline Project
AGENDA ITEM # PAGE
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Attachment B '
Community and Environmental Assessment Process (CEAP) Review for Orodell
Pipeline / Betasso Pipeline /Discharge Pipeline Project
AGENDA ITEM # PAGE
City Of Boulder
Communil]I and Fmironmemal Assessmem Process
Orodell Pipeline/Betasso PenstocN/Daw Water Discharge Protect
Dept otPublic WorNs -Utilities Division
DESCRIPTION AND LOCATION OF THE PROJECT:
The Utilities Division proposes to replace portions of two aging water transmission pipelines
located in the vicinity of Betasso Water Treatment Plant (WTP). Anew pipeline would be
constructed to replace one of the existing pipelines. Both existing pipelines would be
"recycled" to less demanding uses. Completion of this project would increase both
untreated and treated water supply reliability. It would also mitigate treated water quality
problems which can occur during monthly hydroelectric facility generation capacity testing
required by the existing power sale agreement. Revenue from hydroelectric power
generation and for making generation capacity available to Xcel Energy would increase.
Existing and proposed facilities are shown on Figures 1 and 2. All construction would occur
on city-owned land located in Section 34, Township 1 North, Range 71 West in
unincorporated Boulder County. This parcel is crossed by CDOT right-of--way for Highway
119. The project area is southeast of and adjacent to Betasso Preserve (owned by Boulder
County Parks and Open Space).
Orodell Pipeline transports treated water from the Betasso WTP to the Orodell Hydroelectric
Plant and then into the city's treated water transmission system in Boulder Canyon. The
Orodell Hydroelectric unit was added to the end of this pipeline in 1987.
Orodell Pipeline is a welded steel pipeline with exterior coal tar enamel coating. The pipe is
reported to vary in outside diameter from 18 to 24 inches. The 24-inch section of the
pipeline was constructed during the 1960s along with the construction of the Betasso WTP
(see Figure 2). This section of the pipeline was connected to the old Boulder City Pipeline.
Prior to the construction of Betasso WTP, the old Boulder City Pipeline transported water
directly from Lakewood Reservoir into the city. Following construction of Betasso WTP,
the Boulder City Pipeline was broken up into the old Lakewood Pipeline, the Orodell
Pipeline and the Boulder Canyon Pipeline. The Orodell portion of the old Boulder City
Pipeline is believed to be 18-20 inches in diameter and was constructed during the early
1950s.
In recent years, portions of this pipeline located in the Boulder Creek floodplain just
upstream of the Orodell Hydroelectric Plant have required repairs due to significant external
corrosion (see Figure 2). Based on an external condition assessment of the Orodell Pipeline
completed in 2006 (TCB 2006), the exterior condition of upland portions of this pipeline is
good. An internal video inspection of the upland section was completed during the fall of
2006. The internal condition of this pipe is adequate for it to be'recycled to a less
SCALE:
1' - 1000'
EXISTING LAYOUT PROPOSED LAYOUT
FIGURE 2
CONCEPTUAL LAYOUT
ORODELL PIPELINE/BETA550 PENSTOCK/RAW WATER DISCHIUiGE PROJECT
demanding application. If this pipe were to continue in use as the high pressure Orodell
Pipeline, it would require replacement in about ten years.
The city delivers municipal raw water supplies from the Middle Boulder Creek
Watershed/Barker Reservoir system to the Betasso WTP using the existing City of Boulder
Pipeline No. 3 (COB #3)~. The end section of COB #3 is called the Betasso PenstockZ. It
consists of a 20-inch-diameter steel pipeline that takes water from the Boulder Canyon
Hydro Penstock just before the Boulder Canyon Hydroelectric Plant turbines. The Betasso
Penstock then extends north under State Highway 119 to the Betasso Hydroelectric Plant
located at the Betasso WTP (Figure 2). After the water runs through the Betasso Hydro
turbine so that it is depressurized, it is delivered into Betasso WTP for treatment and
delivery to Boulder.
The Betasso segment of COB #3 was built in the 1960s. It originally consisted of an unlined
welded steel pipeline with an exterior coal tar enamel coating. Following construction of the
Betasso Hydroelectric Plant in the mid-1980s, the pipeline was lined with cement mortar
lining to protect the pipe from corrosion.
An internal video inspection of this pipeline conducted within the last several years
concluded that the concrete mortar interior lining was in good condition, although it has a
rippled or ridged surface. The ridges in the lining cause a loss of energy in the water flow
due to friction. This in tum reduces water pressure at the Betasso Hydro turbine and
decreases electricity production.
An external condition assessment of this pipeline conducted in 2005 (TCB 2005) concluded
that the exterior of this pipeline is in good condition. An internal video inspection of this
pipe during the fall of 2006 verified that the condition of the lining was as expected from the
previous video inspection and examined the pipeline for interior corrosion. The internal
condition of the pipe was good.
The Utilities Division proposes to construct a new, 30-inch-diameter, welded steel and
concrete mortar lined pipeline to replace the existing 20-inch Betasso Penstock from
Boulder Canyon Hydro to Betasso Hydro. The pipeline would parallel the existing 20-inch
line. The 30-inch pipeline would achieve several significant objectives:
• The new pipeline would allow the city to deliver 30 million gallons per day (MGD) of
water from the Barker system to Betasso WTP, improving redundancy in the city's raw
water delivery system and the city's ability to meet its adopted water supply reliability
criteria.
The existing 20-inch pipeline would continue to serve a significant purpose if a new 30-
inchpipeline is constructed to replace its function as the Betasso Penstock. The 20-inch
pipeline would be reused to replace the upland portion of the existing Orodell Pipeline.
~ Barker Gravity Pipeline, Boulder Canyon Hydro Penstock and Betasso Pipeline together make up the City of Boulder
Pipeline No. 3.
z A penstock is a conduit or pipeline which conveys water to a hydroelectric turbine.
4
The 20-inch pipe is undersized for optimal performance as the Betasso Penstock, but is
sized correctly to serve as the Orodell Pipeline. The pipe used in the existing Betasso
Penstock was designed for high pressure operation and is believed to be in good
condition. Conversion to a less demanding (lower pressure) use as the Orodell Pipeline
would extend the useful life of the pipeline and delay a significant portion of the capital
cost for the eventual replacement of the Orodell pipeline.
The existing Orodell Pipeline would be converted to a discharge line to allow discharge
of raw water from the Betasso and Lakewood Hydroelectric Facilities to Boulder Creek.
This proposed re-use of the existing line would help to alleviate water treatment
problems associated with contractually-required monthly hydroelectric generation
capacity tests performed on the Betasso and Lakewood Hydroelectric units as well as
treated water quality problems which can result from release of a large volume of treated
water into the distribution system during generation capacity testing.
The majority of the proposed construction could be completed without taking the
existing pipelines out of service, allowing the city to continue to use the Barker system
water resources and deliver treated water using the Orodell Pipeline during construction.
The new pipeline would allow Betasso Hydro to achieve its design generation capacity
of 3.2 megawatts (MW) and would increase revenue to the water utility under the
existing power sales agreement with Xcel Energy. Water utility revenue from
hydroelectric power generation offsets utility capital and operating costs that would
otherwise be borne by the city's water users through higher water rates.
Staff believes this project is both environmentally and economically beneficial. Total
construction cost for the preferred alternative for this project is $3.3 million. The
present worth of increased power generation and capacity revenues is $4.5 million. The
project has an estimated payback period of 15-20 years.
BACKGROUND, PURPOSE AND NEED FOR THE PROJECT:
BACKGROUND
Boulder Canyon Hydroelectric Proiect
The Boulder Canyon Hydroelectric Project includes Barker Dam and Reservoir, the Barker
Gravity Pipeline, Kossler Forebay Reservoir, the Boulder Canyon Hydro Penstock and the
Boulder Canyon Hydroelectric Plant. It was constructed by the Central Colorado Power
Company which later became Public Service Company of Colorado (now Xcel Energy) in
1910. The plant began operation with a capacity of 10,000 kilowatts, which was expanded
to 20,000 kilowatts in 1936.
The city began using Barker Reservoir water in the mid-1950s under an exchange right
which allows the city to divert water out of priority at upstream diversions and replace it
with water from other sources at downstream locations. In exchange for diverting water for
storage at Barker Reservoir, the city replaced the water with Baseline Reservoir water or
Colorado-Big Thompson or Windy Gap water released from Boulder Reservoir. The city
purchased the Boulder Canyon Hydroelectric facilities from Xcel Energy in Mazch 2001.
The city purchased Boulder Canyon Hydro to gain more control over the maintenance of the
facilities and to increase the amount of reservoir storage space available for Boulder's
municipal water supply. Previously, up to one-third of the water stored in Barker Reservoir
was used solely to generate power at the Boulder Canyon Hydro plant. PSCo/Xcel placed
most of this water in storage during the spring snowmelt of each year. The water was held
for later release to generate peaking power within the PSCo power grid, most typically by
releasing surges of water through the hydro plant to Boulder Creek for several hours on most
winter evenings. Since the city's purchase of the reservoir and associated facilities, the city
has used almost all of Barker Reservoir storage primarily as a municipal water supply and
secondarily for power generation. Although the city has continued to generate power at the
Boulder Canyon Hydro Plant, the surge flows that flushed into Boulder Creek below the
hydro plant every winter evening as a result of power peaking operations no longer exist.
The city will rarely generate peaking power since very little storage space in Barker
Reservoir will be dedicated to storing water solely for peaking generation. Almost all of the
power currently generated at the Boulder Canyon Hydro Plant is derived from water that is
flowing into Barker Reservoir, but must be released to Boulder Creek to meet demands of
water users with senior water rights.
Betasso Penstock
With the completion of Betasso WTP in the mid-1960s, Betasso Pipeline was built to divert
water from the Boulder Canyon Hydro Penstock bypassing the Boulder Canyon
hydroelectric turbines and transporting the water to the WTP (Figure 3). Betasso Pipeline
was constructed as a welded steel pipeline with operating pressures ranging from
approximately 500 to 900 pounds per square inch. The pipeline is approximately 20 inches
in diameter. A pressure reducing valve (PRV) was installed at the pipeline terminus at
Betasso WTP to dissipate excess pressure in the water prior to treatment. The PRV served
as the only means to reduce pressure on this pipeline until Betasso Hydro was constructed.
The city began investigating and developing hydroelectric generation potential in its
municipal water supply system in the 1980s. Betasso Hydro was constructed at the terminus
of Betasso Pipeline and began commercial operation in 1987 with a rated generation
capacity of 3.2 MW. At the time of Betasso Hydro construction, concrete mortar lining was
added to Betasso Pipeline for internal corrosion protection. Even though Betasso Hydro is
rated at 3.2 MW, it can only achieve a capacity of about 2.4 MW due to the small diameter
of the Betasso Pipeline (referred to as Betasso Penstock after completion of the hydro unit)
and the large head loss associated with the lining in the 20-inch pipe.
An external inspection of the Betasso Penstock was completed in 2005 (TCB 2005). This
inspection concluded that the external surfaces of this pipeline are in good condition and
recommended some minor maintenance, installation of a cathodic protection system to
protect the pipeline from external corrosion, and intemal inspection of this pipeline.
SCHEMATIC OF CITY OF BOULDER RAW WATER SUPPLYIHYDROPOWER SYSTEM
EL. 8184.48
Barker C
Pipeli
Silver Lake Pipeline
Como.Creek
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Lakewood Pipeline
EL. 8185.46
SLP Headgate: EL. 9720 ~ ~
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North Boulder Creek ~~ _._.
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', Middle Boulder Creek _._._ _._._._._ - - -'-
_.--~~,-
'~, ~ EL. 6430.
~~ ~ ~~~~
EL. 7719.43 KOSSLER ~"~ , - -'-~7 HYDRO
RESERVOIR Boulder Creek `~~ New City of Boulder _
Pipeline No. 3A WTP Influent - -
E -- ------- ---' B
Boulder Canyon - EL. 6400
Penstock
- L_-'-~- Proposed Discharge Pipeline
---- CITY
Existing Bifurcation ., PRV ~ [Recycled Pipe]
,.y---~ EXEI
- - - HYDI
BOULDER ORODELL ~_ Existing Orodell
CANYON HYDRO HYDRO Pipeline
Existing
-------- Proposed
;f~~.=x'! Existing
^,~.....
Proposed
Orodell Pipeline
A section of the Orodell Pipeline was constructed during the 1960s along with the
construction of the Betasso WTP. This section of the pipeline was connected to the portion
of the old Boulder City Pipeline which continues down into the Boulder Creek floodplain
and was constructed during the early 1950s. Orodell Hydro was added to the pipeline in
1987. Orodell Pipeline along with Sunshine Pipeline are the only two means to transport
treated water from Betasso WTP to the city.
Orodcll Pipeline has undergone emergency repairs in the recent past to fix leaks that have
occurred along the portion of the 1950s era pipe that is in the Boulder Creek floodplain.
Previous city inspections of portions of this pipeline between Highway 119 and the Orodell
Hydroelectric Facility have concluded this portion of the Orodell Pipeline is in poor
condition. It is being scheduled for replacement under the city's on-going pipe replacement
program.
Inspection of the upland portions of the Orodell Pipeline (Betasso WTP to Highway 119)
was completed in 2006 (TCB 2006). The exterior of this portion of the pipeline appears to
be in good condition, with little external corrosion. An interior inspection of this pipe
conducted in the fall of 2006 concluded that the pipe is adequate for conversion to a less
demanding use as a discharge line.
Betasso, Silver Lake and Lakewood Hydroelectric Plants
Concurrently with the development of the hydroelectric potential of the treated water
delivery system, the city also developed the environmentally and economically feasible
hydroelectric generation potential in its raw water delivery system. Betasso Hydro was
constructed in 1987. Although the Betasso unit has a rated generation capacity of 3.2 MW,
the small diameter and rough interior of the Betasso Penstock limit its actual capacity to
about 2.4 MW.
Hydroelectric generation plans also proposed the Silver Lake and Lakewood Hydroelectric
facilities, which would later be constructed following replacement of the Silver Lake and
Lakewood Pipelines with gravity-pressurized pipelines. The Silver Lake plant was
commissioned in March 1998 with a rated capacity of 3.2 MW, and Lakewood Hydro was
put into commercial operation in July 2004 with a rated capacity of 3.7 MW.
In 1984, prior to completion of any of the three hydroelectric facilities, the city negotiated a
power sale agreement with PSCo (now Xcel Energy) that included all three proposed
facilities. The agreement contains provisions for payment to the city for two different
aspects of the ability to generate electricity. A payment is made at a set rate for every
kilowatt-hour (kWh) that is generated and an additional variable payment is made for
making the capacity to generate electricity available to Xcel3.
s The city receives a small fixed capacity payment for generation capacity at Boulder Canyon Hydro and no capacity
testing is required.
Capacity payments represent considerable revenue to the city water utility. Capacity
payments have increased as each hydro facility included in the contract has come on line.
Capacity payments since completion of the Lakewood facility are summarized in Table 1.
The capacity payment is based on the maximum reading for a one hour period of the
instantaneous combined electrical generation capacity of the Silver Lake, Lakewood and
Betasso hydroelectric facilities for each month. The combined capacity of the three plants is
demonstrated each month through a capacity test involving the operation of all three
facilities at the same time.
Following the capacity test, the capacity payment for the month can be calculated based on
formulas in the power sale contract that rely on a capacity factor. The capacity factor is
defined as:
Capacity Factor = Total actual generation in kilowatt hours for the month
Total potential generation in kilowatt hours for the month
Total potential generation consists of the combined capacity (kilowatts) of the three
hydroelectric plants included in the agreement, as established by the capacity test, times the
number of days in the month times 24 hours per day.
The formulas in the contract are:
$17.84 per kilowatt hour/month of capacity based on the maximum hour
instantaneous combined capacity of the Silver Lake, Lakewood and Betasso units for
the month if the combined capacity factor is 50% or greater than the combined
capacities of the units.
$8.92 per kilowatt hour/month of capacity based on the maximum hour
instantaneous combined capacity of the Silver Lake, Lakewood and Betasso units for
the month if the combined capacity factor is less than 50% of the combined
capacities of the unit.
The capacity payment is maximized by causing the calculated capacity factor to show that
the hydro plants were generating at their maximum amount for more than half of the month.
This is done by carefully regulating inflow to Betasso WTP during the capacity test to reach
the highest hourly generation possible without causing the capacity factor to be less than 50
percent. During these tests, the flow of water through the hydro plants and into Betasso
WTP must be increased to the desired maximum flow rate over aone-hour period, sustained
for aone-hour period and then reduced back down for an hour. At present, all of the water
released from Betasso and Lakewood Hydros during the capacity tests must be delivered
into the WTP for treatment and release into the treated water delivery system, since there is
no significant raw water storage at Betasso WTP and no means by which to discharge excess
water elsewhere.
Capacity test flows almost always exceed the demand for treated water from Betasso WTP.
Flow rates during capacity tests can reach approximately 61.9 cubic feet per second (cfs) for
9
at least one hour with both the Lakewood Pipeline and Betasso Penstock carrying much
more water than they would otherwise. Accommodating this flow increase is easily done in
summer months when the amount of water being run through the Betasso WTP to meet
municipal demands is naturally high. However, at other times of the year when municipal
water demand is low, it can be problematic to increase flow rates during capacity tests to an
amount that greatly exceeds the normal rate of treated water production4. This means that in
some months, it has not been possible to adjust flows sufficiently to produce a high
maximum hour instantaneous generation value while maintaining a capacity factor value
greater than 50 percent and the payment from Xcel has been less than its potential.
Table 1:
Capacity Test Revenue Summary for Silver Lake, Lakewood and Betasso Hydroelectric
Facilities (since Lakewood Hydro began commercial operation):
MONTH 2004 2005 2006
Janua $84,147 $84,147
Februa $84,147 $42,073
March $42,073 $39,252
A ril $47,921 $30,738
Ma $67,141 $134,353
June $129,127 $133,134
Jul $151,332 $134,353 $129,768
Au ust $134,353 $133,157 $131,721
Se tember $60,212 $134,353
October $84,147 $37,918
November $84,147 $42,073
December $84,147 $48,467
TOTALS $598,338.00 $986,882.00 $727,192.00
Bolded figures represent payment for <50% of the maximum hour instantaneous combined capacity; the
remainder of the payments are for 100%.
In the past, operators have planned for winter capacity tests by drawing down treated water
storage facilities prior to the tests to accommodate treated water in excess of the municipal
treated water demand at the time. However, two types of problem remain:
• Water treatment plants operate best when steady flow rates into the plant are maintained.
Significant increases and decreases in WTP inflow, especially in a short time period as
occurs for the capacity tests, require operators to rapidly adjust treatment processes.
Because of the time constraints associated with the capacity tests, there is potential that
treatment chemicals are not precisely set and that filters brought on line are not properly
conditioned. High flow surges (e.g., in the winter when treated water demand is lowest)
cause a hydraulic surge on the sediment basins and filters. The quality of the treated
water may be diminished as a result.
" In addition to the monthly capacity tests, a 4-hour-long capacity test is conducted every five years to prove the reliable
performance of the hydro units and to establish the standard capacity for the next five years. The 4-hour tests are
conducted once in [he summer and once in the winter.
10
• Surges in treated water flow also may cause problems in the distribution system. During
the winter of 2004-2005, the city received rusty water complaints following capacity
testing. This occurred when Booten Reservoir (treated water storage) was out of service
for maintenance resulting in the other treated water storage facilities receiving a greater
than usual flow surge that stirred up rust.
In general, the city attempts to achieve the highest capacity revenue possible while maintaining
treated water quality. Sometimes, it is necessary to forfeit potential revenue to assure that the
quality of municipal drinking water is not compromised. These problems could be alleviated and
capacity payment revenues to the city increased if there were a discharge pipeline capable of
releasing raw water flows that cannot be accommodated by the treatment plant back to Boulder
Creek.
PURPOSES OF AND NEEDS FOR THE PROPOSED PROJECT:
The proposed project meets general goals for the city's water utility, which are:
• Management of facilities to increase the reliability of the municipal water supply system;
• Generation of hydroelectric power where feasible to maximize the city's generation of clean,
renewable energy and power sale revenues while maintaining hydroelectric power
production as a by-product of a water supply system driven by municipal water demand,
and;
• Establishing and maintaining instream flows in North and Middle Boulder Creeks and
Boulder Creek.
INCREASED RELIABILITY OF THE MUNICIPAL WATER SUPPLY SYSTEM
Betasso Penstock Reliability
The city's long term goal for the capacity of Betasso WTP is a sustainable treatment rate of
approximately 46 MGD of water with a maximum short-term capability of up to 50 MGD.
This requires a source water delivery capacity of up to 30 MGD from the Barker system in
combination with 20 MGD from the Lakewood Pipeline. If recommended water velocities
are maintained and if power generation at Betasso Hydro is preserved, the existing Betasso
segment is limited to a maximum delivery of approximately 34 cfs or 22.0 MGD.
Creating a reliable, sustainable means to provide 30 MGD from the Barker system would
allow the city to meet its municipal water demand during times of the year with low
irrigation needs using only the Barker system. This redundancy provides protection against
water shortages in the event one or more of the components of the raw water delivery
system is out of service. It increases the city's flexibility in handling planned or unplanned
outages of its other facilities.
Betasso Penstock is nearing 50 years in age. Pipelines of this age are routinely inspected to
assess their condition as well as to determine what types of maintenance should occur to
maximize their useful life. The city has conducted external and internal inspections of this
pipeline and determined that its condition is adequate to allow its reuse as the lower pressure
Orodell Pipeline.
The city receives approximately 40 percent of its annual raw water needs from the Barker
System. Therefore, replacement of the Betasso Pipeline would have to be designed and
scheduled to allow the existing pipeline to remain in service for the majority of the
construction. During times of the year when irrigation demands in the city are high, an
unplanned outage of more than a few days duration on the Barker system can result in a
need to implement water conservation within the city.
Orodell Pipeline Reliabilitv
Portions of the Orodell Pipeline located in the Boulder Creek floodplain (Highway 119 to
the Orodell Hydroelectric Facility) are in deteriorated condition and are being evaluated for
replacement under the city's on-going pipe replacement program. The exterior of the upland
portion of the pipeline (Betasso WTP to Highway 119) is in good condition and the pipe
wall thickness is sufficient for the proposed conversion to a discharge line based on
inspections conducted in 2006.
Water treated at Betasso Water Treatment Plant is delivered into the city's treated water
system via Orodell and Sunshine Pipelines and a series of hydroelectric and pressure
reducing stations. Sunshine Pipeline is approximately 40 years old. Inspection and
maintenance of this pipeline is anticipated in the near future, and this will require that all
water from the Betasso WTP be delivered via the Orodell Pipeline. For this reason, it is
desirable to increase the reliability of the Orodell Pipeline.
Treated Water Ouality Reliabilitv
Completion of the discharge line component of this project will eliminate the strain placed
on Betasso WTP facilities during monthly hydroelectric generation capacity testing. The
plant will be able to avoid hydraulic surges on the filters and sediment basins caused by
sudden, large increases in plant inflow and the associated potential for reduced water
quality.
The discharge line would also provide a convenient and efficient way to drain Betasso
and/or Lakewood Pipelines when operating conditions dictate the need to do so. During a
pipeline shut-down, the quality of water that has been standing in the pipeline deteriorates.
During the subsequent pipeline start-up, water initially delivered from the pipeline can be
inconsistent and therefore, difficult to treat. The dischazge line would allow standing water
to be discharged to Boulder Creek and provide flexibility in determining when pipeline start-
up inflows could be delivered into Betasso WTP with minimum upset to the water treatment
process.
12
HYDROELECTRIC POWER GENERATION
Replacing the existing Betasso Penstock with a new, 30-inch diameter pipeline would allow
Betasso Hydro to achieve its intended capacity of 3.2 MW. Water delivery constraints
imposed by the existing Betasso Penstock currently limit the capacity of Betasso Hydro to
approximately 2.4 MW. If the intended capacity of Betasso Hydro is restored and assuming
hydroelectric power production is maintained as a by-product of a water supply system
driven by municipal water demand, it is estimated that Betasso Hydro generation will
increase by more than 51,500 MWH of electricity over the life of the facility. The increased
hydroelectric generation would displace the need to burn approximately 27,000 tons of coal
to produce an equivalent amount of energy at a coal-fired generation plant. Estimated
additional generation revenue to the city would be more than $460,000.
A new, 30-inch diameter Betasso Penstock and the provision of raw water discharge
capabilities would permit the city to maximize its hydroelectric capacity revenues by
allowing the city to achieve higher capacity test flow rates in a greater number of months
each year. It is estimated that the present worth of combined capacity payments for Betasso
and Lakewood Hydro could be increased by approximately $4.1 million (see Table 4).
The Utility Division goals also include maintaining hydroelectric power production as a by-
product of a water supply system driven by municipal water demand. It is therefore
imperative that any project which increases hydroelectric generation or capacity do so
without sacrificing water supplies maintained and managed by the city for the purposes of
meeting municipal water demand.
Only water that cannot otherwise be used for municipal purposes by the city would be
released to Boulder Creek through the proposed discharge pipeline. Water that is decreed
for municipal use that is stored in city reservoirs or water that is diverted under the city's
direct flow water rights for immediate municipal use will not be discharged to Boulder
Creek.
Water used by the city solely for hydroelectric generation and then discharged to Boulder
Creek would derive from the Barker system hydropower water right. When Boulder
purchased the Barker Reservoir system, it also acquired PSCo/Xcel's 1906 water right that
allows storage of water solely for later use for hydropower generation. When in priority to
take water, usually during October through March, this water right is presently used to store
water for later release, usually in April and May, for generation at the old Boulder Canyon
Hydroelectric Plant acquired from PSCo/Xcel. This water right cannot be used for storing
water to meet the city's municipal treated water demand because the historic use was for
non-consumptive hydro generation and the water then was discharged to Boulder Creek for
diversion by other water right owners. However, this water right could be used to store
water for power generation at Betasso Hydro if the water could be returned to its historic
discharge point into Boulder Creek at Orodell through the proposed discharge pipeline. It
would be advantageous to run water stored under the 1906 water right through Betasso
Hydro instead of Boulder Canyon Hydro because the Betasso Hydro power sale contract
13
provides the city with more revenue than the Boulder Canyon Hydro contract (see Table 4
for increased revenue), and the Betasso Hydro equipment is newer and more reliable.
1NSTREAM FLOWS
Changing the point of hydroelectric power generation for some of the water available under
the 1906 hydropower water right from Boulder Canyon Hydro to Betasso Hydro will not
have a significant impact on flows in either Middle Boulder or Boulder Creeks. Instream
flow in Middle Boulder Creek below Barker Dam will continue to be maintained by
voluntary releases from Barker Reservoir. Boulder Creek flows near Orodell will be
essentially the same, since the water will be returned to the creek in the same general
location and at the same general time as would occur if it had been discharged from Boulder
Canyon Hydro.
Implementation of this project will not diminish the city's ability to meet instream flow
goals and commitments for North Boulder, Middle Boulder and Boulder Creeks and normal
streamflows would follow the same pattern as at present. Flows in Middle Boulder Creek
below Barker Reservoir would continue to be maintained above the minimum levels of 5 cfs
in May through September and 4 cfs in October through April that were instituted by the
city upon purchase of the Barker system. Flows in Middle Boulder Creek will continue to
exceed the minimum levels most of the time -sometimes by hundreds of cfs such as during
periods of spring runoff and at times when deliveries are made to senior water rights. Flows
in North Boulder Creek would be unchangeds. If a discharge pipeline is constructed, flows
in Boulder Creek during capacity tests would increase during the period of the test.
Anticipated maximum discharge line flow compared to average stream flow is shown in
Table 2.
Table 2
Proposed Discharge Line ODerations -Maximum Flow
MONTH MAXIMUM MINIMUM MAXIMUM MEAN FLOW
TOTAL CAPACITY AVERAGE DISCHARGE FLOW BOULDER
TEST INFLOW DEMAND FLOW (cfs) t CREEK
(cfs) THOUGH PLANT (cfs) Z
cfs
Janua 61.90 17.26 44.64 6.7
Februa 61.90 17.19 44.71 6.4
March 61.90 17.71 44.19 7.4
A ril 61.90 20.30 41.60 15.7
Ma 61.90 25.71 36.19 79.9
' I[ would be posstble to divert water from North Boulder Creek a[ Lakewood Reservoir that is in excess of the City's
municipal water needs from thts source and then discharge the water back to Boulder Creek through the discharge
pipeline for purposes of increasing hydroelectric generation at Lakewood Hydro. The amount of extra water that could
be diverted would be limited both by the City's contractual commitments to the Colorado Water Conservation Board to
provide tnstream flows below Lakewood Reservoir and by the availability of any capacity in Lakewood Pipeline in
excess of municipal water needs. The possibility of dtverting this extra water is an operational decision that can be
made at a later time and is not a part of the proposed action. The economics that are presented in this document do not
include any revenues from power generated through use of extra water delivered at Lakewood Reservoir.
14
June 61.90 31.74 30.16 219.2
Jul 61.90 36.06 25.84 113.9
Au ust 61.90 35.13 26.77 43.3
Se tember 61.90 33.49 28.41 25.1
October 61.90 22.12 39.78 18.8
November 61.90 19.43 42.47 12.5
December 61.90 16.61 45.29 8.3
I. Discharge duration would be approximately 2 hours. Once plant inflow re[ums to demand flow, it will
take about I S minutes to drain the discharge line at a flow of about 5 cfs.
2. Estimates derived by pro~ectmg modeled city operations on historic Boulder Creek hydrology.
The discharge to Boulder Creek from the proposed discharge pipeline during capacity tests
will be short and infrequent (once per month for a few hours). The anticipated short
duration flow increases were analyzed for potential effects on aquatic resources (see "Impact
Assessment," below). It was found that the discharges were not likely to have any
significant impact on the stream ecology.
DESCRIPTION OF THE PROJECT ALTERNATIVES AND SUMMARY OF MAJOR
ISSUES:
Alternative 1 -Continue using the existing facilities until such time that replacement is
required for continuing operation. It is assumed that the portion of the Orodell Pipeline
from Highway 119 to the Orodell Hydroelectric Facility will be replaced in the near future
under the city's on-going pipe replacement program. It is also assumed that the old Boulder
City Pipeline section of the pipeline will need to be replaced within the next 10-15 years
under the city's on-going pipe replacement program.
Alternative 2 -Replace the entire Betasso Penstock from the Betasso WTP to Boulder
Canyon Hydro to maximize system reliability and hydroelectric power generation at Betasso
Hydro. Reuse the existing Betasso Penstock to replace the majority of the Orodell Pipeline.
Reuse the existing Orodell Pipeline as a discharge line to return excess inflows to Betasso
WTP during monthly hydroelectric capacity tests to Boulder Creek. It is assumed that the
portion of the Orodell Pipeline from Highway 119 to the Orodell Hydroelectric Facility will
be replaced in the near future under the city's on-going pipe replacement program. This
alternative would negate the need to replace the old Boulder City Pipeline section of the
Orodell Pipeline within the next 10-15 years. Therefore, there is no Orodell Pipeline
replacement cost associated with this alternative.
Alternative 3 -Replace the entire Betasso Penstock from the Betasso WTP to Boulder
Canyon Hydro to maximize system reliability and hydroelectric power generation at Betasso
Hydro. Reuse the existing Betasso Penstock as a discharge line to return excess inflows to
Betasso Water Treatment Plant during monthly hydroelectric capacity test to Boulder Creek.
It is assumed that the portion of the Orodell Pipeline from Highway 119 to the Orodell
Hydroelectric Facility will be replaced in the near future under the city's on-going pipe
replacement program. However, replacement of the old Boulder City Pipeline will be
required in the next 10-15 years, and estimated replacement costs have been included in the
cost estimate for this alternative.
15
Alternative 1 would not increase the reliability of water delivery to Betasso WTP or address
potential water quality problems associated with hydroelectric capacity tests. It would result
in no additional hydropower production or capacity payments, though it does not require any
initial capital investment.
Alternative 3 addresses many of the purposes and needs of the proposed project, but
includes the added construction costs for replacement of the old Boulder City Pipeline
section of the Orodell Pipeline. Such replacement is anticipated to be necessary within the
next ] 0-15 years assuming it continues to be used for high pressure treated water
transmission. This alternative does not provide for the reuse of Orodell Pipeline thus
sacrificing its potential for use as a discharge line. Alternative 2 would have the additional
benefit of realizing this potential use of the existing Orodell Pipeline.
The degree to which each of these alternatives meets the identified project purposes and
needs is shown in Table 3.
PREFERRED PROJECT ALTERNATIVE:
Staff recommends Alternative 2 because of its ability to meet the identified purposes and needs
of the project while maximizing the reuse of existing materials. Replacement of the entire
Betasso Penstock would also ensure an anticipated life for the pipeline of at least 50 years.
Under Alternative 2, new construction would be required at the ends of both of the reused
pipelines to convert them to the new uses. The "new" Orodell Pipeline would incorporate a
portion of the existing Orodell line from Betasso WTP to the point where it intersects the
existing Betasso Penstock. The existing Orodell Pipeline at this location is believed to be in
good condition. While this section of pipeline would be the oldest pipe in the new Orodell
arrangement, the uppermost portion of the existing Orodell Pipeline experiences the lowest
water pressures. It can reasonably be expected to function for the 50-year period of analysis
with no major capital expenditures.
From the intersection of Orodell Pipeline with the Betasso Penstock to approximately Highway
119, the existing Betasso Penstock would be reused and incorporated into the new Orodell
Pipeline. The Betasso Penstock was originally designed and constructed for high operating
pressures of 500 to 900 pounds per square inch (psi). When converted to use as the Orodell
Pipeline, internal operating pressures will only be about 250 psi. The less demanding use of the
pipeline should allow it to operate efficiently with no major capital expenditures for the 50-year
period of analysis.
Generation of hydroelectric power at Orodell Hydro will neither increase nor decrease if the
Betasso Penstock is used to replace this pipeline. While the overall length of the Orodell
Pipeline will decrease by about 800 feet suggesting additional power potential, Betasso
Penstock is of a slightly smaller diameter (17.8 inch inside diameter) than the existing Orodell
Pipeline and has a rougher interior surface leading to increased friction losses.
16
Table 3
Betasso Penstock/Orodell Pipeline/Raw Water Discharge Line
Summary of Alternatives by Purposes and Needs
Pur ose/Need Alternative 1 Alternative 2 Alternative 3 '
Re uires no ca ital ex enditures /
Increases reliabili of Betasso Penstock / /
Increases reliabili of Orodell Pi eGne /
Rec Iles existin Orodell Pi eline to extend its usefulness to the ci /
Rec Iles existin Betasso Penstock to extend its usefulness to the ci / /
Increases ca acit to deliver Barkers stem water to Betasso WTP to 30 MGD / /
Achieves intended ca acit of Betasso H dro 3.2 MW / /
Mitigates potential treated water quality problems associated with hydro capacity
testin
/
/
Increases renewable ener roduction usin existin h droelectric facilities / /
Increases h droelectric ca acit test revenues / /
Avoids tern orar disturbance of a visible hillside corridor /
Opportunity to improve appearance and quality of vegetation in previously
disturbed area
/
/
Allows existin facilities to remain in use for the ma'ori of construction / /
Construction cost $0 $3.3 million $3.5 million
Present worth of increased eneration and ca aci revenues $0 $4.5 million $4.5 million
Net Present Value $0 $1.2 million $1.0 million
Alternative 1 -Continue using the existing facthties until such time that replacement is required for continuing operation. (It is assumed that the pomon of the Orodell
Pipeline from Highway 119 to [he Orodell Hydroelectric Facthry wtll be replaced under the city's on-going pipe replacement program)
Alternative 2 -Replace the entire Betasso Penstock from the Betasso WTP to Boulder Canyon Hydro to maximize system reliability and hydroelectric power generation at
Betasso Hydro. Reuse the existing Betasso Penstock to replace the majority of the Orodell Pipeline. Reuse the existing Orodell Ptpehne as a discharge tine to return excess
inFlows to Betasso Water Treatment Plant during monthly hydroelectric capacity test to Boulder Creek (It is assumed that the portion of the Orodell Pipeline from Highway
119 to the Orodell Hydroelectric Facility will be replaced order the city's on-going pipe replacement program )
Alternative 3 -Replace the entire Betasso Penstock from the Betasso WTP to Boulder Canyon Hydro [o maxim¢e system reliabthty and hydroelectric power generation at
Betasso Hydro. Reuse the existing Betasso Penstock as a discharge Ime to return excess inflows to Betasso Water Treatment Plant during monthly hydroelectric capacity test
to Boulder Creek. (It is assumed [hat the portion of the Orodell Ptpehne 4om Highway 119 to the Orodell Hydroelectric Facility will be replaced under the city's on-going
pipe replacement program.)
i~
The existing Orodell Pipeline will function as an adequate raw water discharge line with
limited repairs. Leaks could be repaired more easily since the pipeline would not be required
to deliver treated water to the city's customers and would be used only intermittently.
Approximately 300 to 500 feet of new discharge pipeline will be required to deliver water
from the hydroelectric plant discharges to the existing Orodell Pipeline. A short stretch of
new pipe would be needed from the north side of Highway 119 to Boulder Creek. A pressure
reducing valve and vault would be constructed adjacent to Boulder Creek to dissipate excess
energy in the waterb prior to its release to the stream.
A preliminary estimate of costs and benefits of Alternatives 2 and 3 is contained in Table 4.
Maintenance of the Orodell Pipeline under from Highway 119 to Orodell Hydro is
considered a separate project and therefore, costs associated with this effort are not included
in this analysis.
PUBLIC INPUT TO DATE:
An initial presentation and project introduction was made to the Water Resources
Advisory Board in August 2006, which was the first opportunity for public
comment on this project. No public comments were made during the August
WRAB meeting. A public hearing for this project will occur during the
November 2006 WRAB meeting.
STAFF PROJECT MANAGER
Joseph J. Taddeucci (303) 441-3205 taddeuccij~a~bouldercolorado.gov
OTHER CONSULTATIONS OR RELEVANT CONTACTS
Ned Williams, Director of Public Works for Utilities 303 441-3200
williamsn(a~bouldercolorado. Qov
Robert Harberg, Utilities Project Coordinator, 303 441-3124
harbergb(a bouldercolorado.gov
Carol Ellinghouse, Water Resources Coordinator, 303 441-3118
cllinehousec(a bouldcrcolorado.eov
Rajesh Dham, Project Manager, TCB/AECOM, 303 298-7117
rajesh.dhamna,tcb.aecom.com
° Installation of a hydroelectric turbine at [his location is not economically feasible due to the limited use of the
dischazge line (a few hours once each month).
18
Table 4
Betasso Penstock/Orodell Pipeline/Raw Water Discharge Line
Environmental and Financial Summaries for Alternatives 2 and 3
Alternative 2: New 30" Pi eline and Rec sled Orodell Dischar a Line O lion Preferred Alternative
Energy Rate for all facilities = $0.02
Environmental Summary Financial Summar
Total
Incremental
Equivalent
Equivalent
Equivalent
Equivalent Incremental
Present Worth Revenue
Total
Construction
Net Present
Facili Energy
(MW-hr) amt of Coal
(tons) amt of SOi
(tons) amt of NOx
(tons) amt of COZ
(tons) Energy
Pa men[s Capacuy
Pa ments Revenue Cost Value
New 30" Pi eline -- -- -- -- -- -- -- -- $3,285,000
Betasso H dro 51,500 26,500 40 80 26,800 $456,000 $2,700,000 $3,156,000 $0
Stlver Lake H dro $655,000 $655,000 $0
Lakewood H dro $724,000 $724,000 $0
Total 51,500 26,500 40 80 26,800 $456,000.00 $4,079,000.00 $4,535,000.00 $3,285,000 $1,250„000
Alternative 3: New 30" Pi eline and Rec cled Betasso Penstock Dischar a Line O lion
Energy Rate3 for all facilities = $0.02
Environmental Summar Financial Summar
Total Incremental Net
Incremental Equivalent Equivalent Equivalent Equivalent Present Worth Revenue Total Construction present
Energy amt of Coal amt of SOZ amt of NOx amt of COr Energy Capacity Revenue Cost Value
FaciliTy (MW-hr) (tons) (tons) (tons) (tons) Pa menu Pa ments
New 30" Pi eline -- -- -- -- -- -- -- -- $3,015,000
Betasso H dro 51,500 26,500 40 80 26,800 $456,000 $2,700,000 $3,156,000 $0
Silver Lake H dro $655,000 $655,000 $0
Lakewood H dro $724,000 $724,000 $0
Orodell Pipeline
Re lacement $514,000
Total 51,500 26,500 40 80 26,800 $456,000.00 $4,079,000 $4,535,00000 $3,529,000 $1,006,000
1. Total annual revenue for both Alternatives 2 and 3 is estimated to be $216,000.
2. Present value calculations assume a discount rate of 4°/ and an amortization penod of 50 years.
Source: Final Summary Report, Betasso Water Treatment Plant Pipelines Project, TCB/AECOM, September 2006.
)9
Goals Assessment:
1. Using the BVCP and department master plans, describe the primary city goals and
benefits that the project will help to achieve:
Sustainability -General Policy 1.02 (Principles of Environmental Sustainability) of the
BVCP acknowledges the importance of natural capital, which can be kept at healthy levels
for the long term only when we are able to do the following:
a) Renewable resources should not be used faster than they are recharged or replenished by
the environment.
b) Non-renewable resources should be used with the greatest care and efficiency, and some
of those should be used to develop renewable replacements.
c) Waste should not be dumped into nature any faster than nature can absorb it.
This project is in keeping with General Policy 1.02 because it increases renewable energy
generation using existing facilities and reuses non-renewable industrial resources (steel pipe)
to the maximum extent possible.
Environment -The 2005 update of the BVCP states:
"The City Council has established the goal of becoming a nationwide environmental
leader among communities and a role model for exemplary environmental practices. The
city seeks to institute state of the art policies in prioritized areas for both the community
and the city government organization. Environmental priorities set by the City Council
include reducing pesticide use, reducing waste and over-use of resources by promoting
re-use and recycling, reducing greenhouse gas emissions, promoting energy efficiency
and water conservation, continuing our strong leadership in preserving native plant and
wildlife habitat, and strengthening our efforts to improve air and water quality."
This project directly addresses the City Council goals for promoting re-use and recycling and
reducing greenhouse gas emissions.
Goa14.06 of the BVCP commits to protection and restoration of significant native ecosystems,
with emphasis on protection of biological diversity and habitat for threatened and endangered
species. Goals 4.09 (Wetland Protection) and 4.10 (Invasive Species Management) support the
protection of native ecosystems and biological diversity. This project will provide an
opportunity to correct poor restoration and revegetation of previous construction and
manage/reduce weed species, thus restoring native plant communities. These aspects of the
project are discussed further in CEAP checklist discussions, below (see CEAP Checklist Section
A).
Goa14.18 states that hillside and ridge-line development will be carried out in a manner that, to
the extent possible, avoids both negative environmental consequences to the immediate and
surround area and the degrading of views and vistas from and of public areas. Pipeline
construction of the 1960s era included little attention to restoration and revegetation of
construction areas. Even 40+ years after Betasso Penstock construction, there is a highly visible
linear scar on the hillside (Figure 4A). This project will provide an opportunity to proactively
20
restore and revegetate the landscape disturbed by previous construction to achieve a more
aesthetic and natural appearance in the future. The city's restoration and revegetation efforts for
the Lakewood Pipeline Phase III replacement project have become models of steep slope
restoration and successful revegetation strategies (Figure 4B).
Goa14.29 commits to meeting secondary drinking water standards established by the EPA and
seeking to improve the quality of drinking water. The provision of a discharge line to return
excess inflows to the hydroelectric plants during capacity testing will mitigate a situation that has
the potential to negatively affect Betasso WTP treated water quality.
Goa14.36 identifies the city's goal of being in alignment with the Kyoto Protocol target of
reducing greenhouse gas emission seven percent below 1990 levels. Production of renewable
hydroelectricity offsets the need to generate an equivalent amount of power at a fossil fuel based
power production plant. Reductions in emissions that will result from this project are shown in
Table 4.
The May 2006 issue of Water Power suggests potential additional benefits from contributing to
achievemerit of Kyoto Protocol targets:
"The period of political uncertainty over the Kyoto Protocol and its instruments such as
the Clean Development Mechanism (CDM) is over, and early risk-takers in the carbon
market have gained large financial rewards from investing in emissions reduction
projects. Greenhouse gas mitigation is now mainstream and makes clear business sense,
with the CDM becoming a well established international financing mechanism creating
billions of dollars in future carbon revenues, and leveraging billions more in investments
in renewable energy and other sectors.
The Kyoto Protocol established for the first time binding emissions reduction targets for
industrialized countries, part of what many see as an evolving process ofever-stricter
targets. The Protocol's new "flexible mechanisms" for carbon trading allow emissions
reductions achieved in one country to be bought by other countries struggling to meet
their own targets. The costs of meeting these targets and the resultant global reduction in
greenhouse gases therefore should be achieved at minimum cost. This is the world's first
truly international environmental mazket, and carbon the first globally traded
environmental commodity."
Goal 4.39 commits to the development of renewable energy resources where economical. This
project is economically feasible and will increase the city's generation of hydroelectricity using
existing hydroelectric facilities.
21
Figure 4
Steep Slope Revegetation
A. View of Betasso Penstock corridor from above Boulder Canyon Hydro plant (40+ years
after disturbance).
B. Steep slope revegetation on the Lakewood Pipeline Phase III reconstruction (3 years
following disturbance).
22
Economy -Goal 5.10 of the BVCP expresses the city's desire to encourage a strong sustainable
economy to fund quality city services for the public that are consistent with community goals
and character. This project furthers the city's renewable energy goals at a reduced cost due to
the recycling of existing facilities, while increasing revenues for hydroelectric capacity and
generation, thus offsetting water utility improvement costs that would otherwise be paid for by
the city's water users.
The city's Raw Water Master Plan (adopted in 1989) recommended improved management of
the city's water holdings and some capital projects, many of which have been implemented.
Repair and replacement of aging infrastructure is recognized as an on-going need.
The city's Treated Water Master Plan was revised and adopted in 2000. As a part of the master
planning process, the city adopted the following reliability criteria for delivery of treated
water:
1. The city will ensure the delivery of the water required to satisfy essential needs including
the maintenance of basic public health, safety and welfare such as indoor domestic,
commercial and industrial uses and fire fighting uses, except for droughts and system
failures having a frequency of no more than once in 100 years. The average winter
consumption plus a fireflow reserve demand is established as a measure of this demand.
2. The city will ensure delivery of the water required to provide for the continued
viability of exterior landscaping, except for droughts and system failures having a
frequency of no more than once in 50 years. The following method is used to establish a
measure of this demand:
ELD =AWC + 0.65 * (PMD -AWC)
WHERE:
ELD =Exterior Landscaping Demand
AWC =Average Winter Consumption
PMD =Peak Month Demand
As an alternative, 75 percent of the peak month demand may be established as a measure
of this demand.
3. The city will ensure delivery of the water required to fully satisfy all uses, except for
droughts and system failures having a frequency of no more than once in 20 years. The
peak hour demand or the peak day demand plus afire-flow reserve demand is established
as a measure of this demand.
4. Providing redundant facilities where practical will minimize complete interruptions to the
delivery of water.
5. A reserve capacity of 10 percent will be maintained in the water delivery system. The
maintenance of such a reserve capacity will allow a degree of planning flexibility and
mitigate water delivery problems that might be caused by operator error.
23
This project will improve the reliability of the treated water supply by increasing the capacity
of the Betasso Penstock, while extending the serviceable life of both the penstock and
Orodell Pipeline. Redundancy in water supply will be increased if the city's capacity to
deliver Barker system water to Betasso WTP is increased to 30 MGD.
2. What are the trade-offs among city policies and goals in the proposed project
alternative? (e.g. higher financial investment to gain better long-term services or fewer
environmental impacts)
The Treated Water Master Plan acknowledges the industry-wide problem of aging
distribution piping and recommends that the city replace one percent of its distribution piping
each year to keep up with system aging. This project will involve capital expenditure to
replace some pipe that is not seriously deteriorated at the current time. Funding of other
projects to replace aging pipe could be considered a higher city priority.
Implementation of the preferred alternative for this project will, however, result in increased
revenue to the city from hydroelectric capacity payments and power generation. Based on
preliminary estimates of construction costs and revenue projections, this project will have a
pay-back period of approximately 15 to 20 years.
The preferred alternative also delays the need for complete replacement of the Orodell
Pipeline with new pipe. The Orodell Pipeline will be co-located for a significant portion of
its length with the Betasso Penstock corridor, reducing its length by approximately 800 feet.
Co-location of linear utility corridors is in general regarded as a good land use strategy.
This project will result in temporary environmental disturbance of a lineaz corridor that is
visible from Boulder Canyon and other vantage points. However, advancements in
restoration and revegetation methods and technologies since the original construction can be
employed during this project to correct the environmental damage that resulted from original
construction of the pipelines. Preliminary costs for restoration and revegetation of areas
disturbed by construction and post-construction weed control indicate that these efforts will
add approximately $125,000 to the cost of the project. However, it will reduce the visual and
aesthetic impact of these pipelines.
3. Is this project referenced in a master plan? If so, what is the context in terms of goals,
objectives, larger system plans, etc.? If not, why not?
Both the Raw Water Master Plan (adopted 1989) and Treated Water Master Plan (adopted
2000) refer to the need to replace aging and deteriorated transmission pipelines.
This project will increase the reliability of the city's water supply system and increases
redundancy of facilities to minimize interruptions to the delivery of water. This project will
also develop environmentally and economically feasible hydropower generation.
24
4. Will this project be in conflict with the goals or policies in any departmental master
plan?
Utilities Division staff has no knowledge of conflicts with any departmental master plan.
5. List other city projects in the project area that are listed in a departmental master
plan or the CIP.
The CIP includes on-going maintenance, repair and modification to the Barker system
facilities to increase the reliability of this water supply.
6. How could the project exceed city, state, or federal standards and regulations (e.g.
environmental, health, safety, or transportation standards)?
This project will not exceed city, state or federal standards and regulations.
Impact Assessment
Using the attached checklist, identify the potential short or long-term impacts of the
proposed project or (if applicable) the project alternatives.
Note: Impacts associated with maintenance of Orodell Pipeline from Highway 119
to Orodell Hydro are not included in this analysis.
25
City Of Boulder
Communigl and Emironmemal Assessmem Process
[E>.plained in writing below?
Checklist
+ Positive effect
- Negative effect
0 No effect
Project Title:
BetasSO Pe11S[oCIUBrodeIl Pipeline/Dlscbarge Pipeline
N e+l
d d Q d
7 ~ 9 7
~ A ~ ~
d d y
` d
a
A. Natural Areas or Features
1. Disturbance to species, communities, habitat, or ecosystems due to:
a. Construction activities 0
b. Vegetation removal 0
c. Human or domestic animal encroachment 0 0 0
d. Chemicals (including petroleum products, fertilizers, pesticides, p
herbicides
e. Behavioral displacement of wildlife species (due to noise from use 0
activities
f. Introduction of non-native plant species in the site landscaping 0 + +
g. Changes to groundwater or surface runoff 0 0 0
h. Discharge of sediment to any body of water 0 0 0
i. Wind erosion 0 0 0
2. Loss of mature trees or significant plants? p
B. Ri avian Areas/Flood lains
1. Encroachment upon the 700-year, conveyance ore high hazard flood zones? p
2. Disturbance to or fragmentation of a riparian corridor? 0
C. Wetlands
26
1. Disturbance to or loss of a wetland on site? o ~ ?
D. Geolo and Soils
1. a. Impacts to unique geologic or physical features? 0 0 0
b. Geologic development constraints? 0 0 0
c. Substantial changes in topography? 0 0 0
d. Changes in soil or fill material on the site? 0 0 0
E. Water Quali
1. Im acts to water uali from an of the followin ?
a. Excavation p
b. Change in hardscape 0 0 0
c. Change in site ground features 0 0 0
d. Change in storm drainage 0 0 0
e. Change in vegetation p
f. Change in pedestrian and vehicle traffic 0 0 0
g. Use or storage of chemicals 0 0 0
2. Exposure of groundwater contamination from excavation or pumping? 0 0 0
F. Air Qualit
1. Short or Ion term im acts to air uali CO2 emissions, ollutants 7
a. From mobile sources? p
b. From stationary sources? 0 + +
G. Resource Conservation
1. Changes in water use? 0 0 0
2. Increases in energy use? 0 0 0
3. Generation of excess waste? 0 0 0
H. Cultural/Historic Resources
27
1. a. Impacts to a prehistoric or archaeological site? 0 0 0
b. Impacts to a building or structure over fifty years of age? 0 0 0
c. Impacts to a historic feature of the site? 0 0 0
d. Impacts to significant agricultural land? 0 0 0
I. Visualllualit
1. a. Effects on scenic vistas or public views? 0 0 0
b. Effects on the aesthetics of a site open to public view? 0
c. Effects on views to unique geologic or physical features? 0 0 0
J. Safe
1. Health hazards, odors, or radon? 0 0 0
2. Site hazards? 0
K. Ph siolo ical Well-bein
1. Exposure to excessive noise? 0 0 0
2. Excessive light or glare? 0 0 0
3. Increase in vibrations? 0 0 0
L. Services
1. Additional need for:
a. Water or sanitary sewer services? 0 0 0
b. Storm sewer/Flood control features? 0 0 0
c. Maintenance of pipes, culverts and manholes? 0 + +
d. Police services? 0 0 0
e. Fire protection services? 0 0 0
f. Recreation or parks facilities? 0 0 0
g. Library services? 0 0 0
h. Transportation improvements/traffic mitigation? p
i. Parking? 0 0 0
28
j. Affordable housing? 0 0 0
k. Open space/urban open land? 0 0 0
I. Power or energy use? 0 0 0
m. Telecommunications? 0 0 0
n. Health care/social services? 0 0 0
M. S ecial Po ulations
1. Effects on:
a. Persons with disabilities? 0 0 0
b. Senior population? 0 0 0
c. Children? 0 0 0
d. Restricted income persons? 0 0 0
DISCUSSION OF PROJECT EFFORTS
(as outlined above)
A. Natural Areas or Features
1. Disturbance to species, communities, habitat or ecosystems due to:
la. Construction Activities
Pipeline construction proposed for Alternatives 2 and 3 will involve excavation of a
trench in which to install pipe and use of aeeas adjacent to the trench For a variety of
construction activities, which will cause temporary disturbance of the environment.
Careful project design and construction can minimize adverse effects to species,
communities, habitat or ecosystems.
ERO Resources Corporation has completed an inventory of natural resources within the
project areas which would be disturbed by construction of the preferred alternative for
this project. The sensitive environments that have been identified aze listed in Table 5,
below and are discussed in subsequent sections of this report.
29
Table 5
Orodell Pipeline/Betasso PenstocWRaw Water Discharge Project
Criteria and Determination of Sensitive Environmental Issues
Criteria Determination
Wetlands Contains any jurisdicnonal wetlands or waters Boulder Creek is a jurisdictional water of the
of the U.S. or any wetlands requiring city of U.S.; two wetlands meet the city of Boulder
Boulder permitting. wetland criteria.
Federally Located within any critical habitat for No critical habitat in project azea.
Threatened federally designated threatened or endangered potential habitat for the Preble's meadow
and species. lumping mouse.
Endangered Provides any significant habitat for a federally
(T&E) designated threatened or endangered species.
Species
State T&E Is determined to serve as stgnificant habitat Potential habitat for northern leopard frog,
Species and for any of the species on [he Colorado American peregrine falcon, common garter
State Species Division of Wildlife's Colorado Ltsnng of snake, and Townsend's big-eared bat.
of Concern Endangered and Threatened Wildlife Species
and Species of Special Concem (June 2006).
Colorado Is determined to provide significant habitat for Project area provides habitat for two butterflies
Natural rare or imperiled species as defined by CNHP. and one plant community.
Heritage
Program
(CNHP)
Migratory Presence of nests or nesting habitat for Project area provides habitat for migratory
Bird Treaty migratory birds. birds.
Act
Noxious Presence of noxious weeds listed to the Noxious weeds from List B and List C are
Weeds Colorado Noxious Weed Act (Lists A, B or present.
C).
Vegetation Communities
Two vegetation communities occur within the project area: riparian/wetland areas and
ponderosa pine forests. Riparian and wetland areas occur along Boulder Creek; the
remainder of the vegetation in the project azea is ponderosa pine forest. Additionally,
some landscaped areas are maintained and mowed along the access road to the Boulder
Canyon power plant.
Riparian and wetland areas are located along Boulder Creek. Another small
intermittent drainage crosses the project area, but no riparian or wetland areas occur
along this drainageway. The dominant vegetation of these areas includes plains
cottonwood (Populus deltoides), crack willow (Salix fragilis), snowberry
(Symphoricarpos adbus), chokecherry (Prunus virginiana), horsetail (Eguisetum arvense),
small Solomon's seal (Polygonatum bijlorum), wooly sedge (Carex lanuginose), redtop
(Agrostis alba) and Wood's rose (Rosa woodsii). Other species present include
ponderosa pine (Pinus ponderosa), orchard grass (Dactylis glomerata), Canada wildrye
(Elymus canadensis), peach-leaf willow (Salix amygdaloides), wax currant (Ribes
cereum), Siberian elm (Illmus pumila), ragweed (Ambrosia artemisiifolia), and narrow-
leafcottonwood (Populus angustifolius).
30
Ponderosa pine forests cover the majority of the project area, especially the steep, rocky
slopes above the creek. The existing pipeline runs through previously disturbed areas and
under a trail through ponderosa pine forest areas. Common plant species in the
understory of this vegetation type include squirreltail (Sitanion hystrix), needle-and-
thread (Stipa comata), snowberry, crested wheatgrass (Agropyron cristatum), cheatgrass
(Bromus tectorum), curlycup gumweed (Grindelia squarrosa), smooth brome (Bromus
inermis), and weedy species. Siberian elm, in both tree and shrubby growth form, is also
common in flatter portions of the ponderosa pine forest.
• Threatened and Endangered Species (Federal)
The Preble's meadow jumping mouse (Preble's) is listed as threatened under the ESA.
Typically, Preble's is located in low undergrowth consisting of grasses and forbs, in open
wet meadows, riparian corridors near forests, or where tall shrubs and low trees provide
adequate cover. Along Colorado's Front Range, Preble's is found below 7,800 feet in
elevation, generally in lowlands with medium to high moisture along permanent or
intermittent streams and irrigation canals (Meaney et al. 1997).
The project area has marginally suitable habitat for Preble's meadow jumping mouse.
The riparian habitat is somewhat narrow in most locations along Boulder Creek, and
slopes are steeper than is considered optimal habitat. No trapping surveys have been
conducted along Boulder Creek within 5 mites of the project area, although trapping
surveys have been conducted on nearby drainages. In 2001, Preble's was trapped and
found on Upper Bear Creek about 1.3 miles east of the project area, and in Long Canyon
about 1.7 miles southeast of the project area. In 2000, habitat along Bummers Gulch 1.7
miles northwest of the project area was trapped and no captures were made.
Based on this information, ERO recommended that a letter be prepared for submittal to
the U.S. Fish and Wildlife Service (USFWS) regarding potential Preble's habitat in the
project area. Staff will consult with USFWS when the nature and extent of proposed
impact to Preble's habitat can be more precisely defined.
• Threatened and Endangered Species (State)
There are numerous species in Boulder County considered state species of special
concern by the CDOW. The project area contains potential habitat for four state species
of special concern in the project area. There are no regulations that protect these species.
The northern leopard frog (Rana pipiens) prefers the banks and shallow portions of
marshes, wet meadows, ponds, lakes, and streams particularly where rooted aquatic
vegetation is present (Hammerson 1999). They prefer permanent bodies of water and are
awide-ranging species known to elevations of 11,000 feet. Northem leopard frogs can
range up to 3 miles and feed on insects, spiders, and worms. Northem leopard frog
tadpoles are herbivorous scavengers (USFS 1997). Potential leopard frog habitat occurs
along Boulder Creek in the project area.
The American peregrine falcon (Falco peregrinus) has made a remarkable recovery
from the brink of extinction and has recently been removed from both the State of
Colorado and federal endangered species lists. Currently the peregrine falcon is listed as
a State Species of Special Concern. Peregrines nest on high steep cliffs generally along
stream courses. Peregrine falcons migrate through eastern Colorado and nest in canyons
31
and cliffs along the Front Range. Peregrine falcons may occasionally forage at the
project area, but are unlikely to nest near the project area due to the lack of high cliffs.
The Townsend's big-eared bat (Plecotus townsendii) is a medium-sized bat that occurs
over the western two-thirds of the state. This species is apparently globally secure, but is
becoming increasingly rare along the periphery of its range, including Colorado where
the species is listed as a state species as special concern. The Colorado Natural Heritage
Program has listed this species as imperiled (CNHP 2005). The Townsend's big-eared
bat is a year-round resident in Colorado, and often does not move much from winter
hibemaculum to summer roost sites (Fitzgerald et al. 1994). This species is extremely
sensitive to human activity and is susceptible to die-offs during hibernation if disturbed.
Townsend's big-eared bats inhabit woodland areas with rocky outcrops, vacant buildings,
caves and old mine shafts (Fitzgerald et al. 1994).
The project area contains potential habitat for the Townsend's big-eared bat. The species
could potentially inhabit rocky areas along the hogbacks and foothill areas, as well as old
buildings, small caves. Noise from the highway, power plant, and WTP may discourage
use of habitat by the bat.
The common garter snake (Thamnophis sirtalis) inhabits marshes, ponds, and edges of
streams. In Colorado, the common garter snake is restricted to floodplains of the South
Platte River and its tributaries (Hammerson 1999). In Colorado, this species is seldom
found far from water (Hammerson 1999). A garter snake was observed at the site during
the site visit, but was not observed closely enough to determine if the specimen was the
common garter snake. The project area has potential habitat for the common garter
snake.
• Colorado Natural Heritage Program
The Colorado Natural Heritage Program (CNHP) maintains a list of species considered
rare or imperiled in Colorado. These species are not formally protected but are
considered rare or declining by CNHP. The CNHP maintains a list of species
occurrences by USGS 7.5 minute quadrangle. Potential habitat for two species listed by
the CNHP occurs within the project area.
The Moss' elfin butterfly (Callophrys mossii schryveri) occurs on the western mountain
chains from British Columbia to southern California and southern Colorado. Generally,
the species is uncommon throughout its range, and is considered imperiled to vulnerable
in Colorado (CNHP 2005). This grayish brown butterfly occurs in moist slopes and
canyons usually with steep topography on thin-soiled or rocky north-facing slopes. The
caterpillar feeds on yellow stonecrop and other members of the stonecrop family. Adults
feed on the nectars of a variety of flowers (CNHP 2005). Although it is not known if
yellow stonecrop occurs in the project area, these rocky outcrops may provide habitat for
the Moss' elfin's caterpillar host plant.
The two-spotted skipper (Euphyes bimacula) occurs in northeast Colorado and western
Nebraska; eastern Nebraska east to southern Quebec; southern Maine south to central
Virginia; coastal plain south to Georgia; and the Gulf Coast. The butterfly inhabits
marshes, bogs, wet streamsides, and wet sedge meadows. Caterpillars feed on hairyfruit
sedge (Carez trichocarpa), and adults feed on nectar from flowers including
32
pickerelweed, sweet pepperbush, blue flag, common milkweed, and spiraea. Milkweed
was observed during the site visit, and although Carex trichocarpa was not observed, a
similar species (Carex lanuginosa), was observed. The project area may provide habitat
for the two-spotted skipper.
• Aquatic Habitat/Fisheries
The raw water discharges associated with Alternatives 2 and 3 for this project will range
from approximately 26 to 45 cfs to Boulder Creek for about 2-3 hours per month. Dr.
William J. Miller used data from the 1994 instream flow analysis for Boulder Creek to
evaluate potential discharge impacts to aquatic resources (Miller Ecological Consultants
2006). He concluded that the short duration change in flow in Boulder Creek would
result in an increase in habitat and wetted azea. However, the short duration would likely
not result in any detectable change in aquatic resources. While there may be some
additional drift of aquatic invertebrates due to the increased velocity, the depth and
abundance of boulders in the stream channel should provide refuge for fish during the
increase in velocity. If flows are slowly ramped from base to maximum flow (e.g., 5-10
cfs every 15 minutes), there should be adequate time for fish to establish new stream
positions to avoid impacts. This same rate should be used in reducing flow following the
monthly hydroelectric capacity tests. The short duration of flow change in Boulder Creek
is likely not measurable at the population level for the fish and invertebrates. Habitat
change due to discharge line operations is summarized in Table 6.
Table 6
Orodell Pipeline/Betasso Penstock/Raw Water Discharge Project
Effects of Discharge Line Operation on Boulder Creek Aquatic Habitat
Boulder Creek Aquatic Habitat
(square feet per 1000 feet of stream)
Juvenile Adult
Existing Condition 8353 1627
Proposed Condition 9816 2206
Percent Change 15% 26%
lb. Vegetation Removal
Vegetation will be removed from the construction corridor. Following completion of
construction, the disturbed area will be seeded and planted with grasses, forbs, shrubs and
trees as appropriate. A detailed revegetation plan will be developed during project design
to specify species, seed mixtures, application rates, follow-on care, etc.
33
Preliminary examination of this azea suggests that importation of additional topsoil will
not be necessary to achieve successful revegetation in this area. However, due to the
steepness of the construction areas, jute matting of disturbed ground on the slopes above
Highway 119 will be required.
ld. Chemicals
Negative effects have been indicated on the CEAP checklist for this item because pre-
construction application of an herbicide to control the existing weeds infestation of the
project azea has been recommended. Staff believes that pre-construction herbicide
application can be accomplished without negative short- or long-term effects.
Weeds listed in the Colorado Noxious Weed Act (8 CCR 1206-2) are common in the
project area. Along the roads and riparian areas in the project area, List B noxious weed
species present are Canada thistle (Cirsium arvense), teasel (Dipsacus fullonum),
bouncingbet (Saponaria oj~cinalis), yellow toadflax (Linaria vulgaris), spotted
knapweed (Centaurea maculata), and diffuse knapweed (Centaurea diffusa). List C
species found in the project area along roads/riparian areas include chicory (Cichorium
intybus) and field bindweed (Convolvulus arvensis). In the ponderosa pine forested areas
and near the WTP, common List B weed species include yellow toadflax (Linaria
vulgaris), spotted knapweed (Centaurea maculata), and diffuse knapweed (Centaurea
diffusa). List C species include cheatgrass. No species from List A were observed.
ERO recommends implementing weed control measures in both fall and spring because
both perennial and biennial weed species are present. ERO recommends spraying in the
fall, and mowing/weed whacking and spraying again in the spring. Spring mowing is
suggested to remove newly grown foliage before it has time to reproduce. The
recommended combination of spraying and mowing, as well as implementing a seeding
and revegetation plan, will help control the spread of weeds. Revegetation of disturbed
areas is an important part of noxious weed control efforts.
For weeds close to wetlands and other water resources, the chemical glyphosphate
(RodeoT"') was recommended by ERO. Any time herbicides are used, care should be
taken to ensure a safe application. For this project, it is recommended that only direct
application be performed using a backpack sprayer so that over spray and drift will be
avoided. The recommended rates and safety precautions listed on the label of each
herbicide should be followed. Shrubs, open water, and wetlands should be avoided. The
following pre-construction weed control measures have been recommended:
As soon as possible:
Mow Canada thistle and teasel. Remove any flowering plants from the site.
• Chemically treat thistle, knapweed, bouncingbet and yellow toadflax.
34
Late August/Early September 2006:
Chemically treat remaining individuals or stands of Canada thistle, knapweed, and
yellow toadflax.
April-May 2007 (or prior to construction activity):
• Mow Canada thistle and knapweed. Remove any flowering plants from the site.
• Chemically treat thistle, knapweed, bouncingbet and yellow toadflax.
ERO's weed control recommendations were based upon aspring/summer 2007
construction season. These recommendations were corroborated by Dr. Denise Arthur of
ESCO Associates.
CDOT was contacted concerning policies and procedures for herbicide application on
CDOT right-of--way. While CDOT is not adverse to the use of RodeoTM or similar
products, CDOT encourages the use of a product named MilestoneTM with or without the
use of additives, because it will kill the targeted weed species but not grasses, forbs and
other vegetation.
Kathleen Alexander, the city's Integrated Pest Management Program Manager, was
contacted concerning the proposed use of herbicides prior to construction. Ms.
Alexander recommended that RodeoTM be used for preconstrnetion weed control on city
property since MilestoneTM is not currently on the city's list of herbicides approved for
use on city land. However, since it is anticipated that it will be included on the updated
list to be produced in 2007, staff applied to the City Manager for aone-time emergency
exemption to allow the weed infested areas to be treated with MilestoneTM during the fall
of 2006. The emergency exemption was granted under the city's special approval
process for non-listed herbicides effective October 16, 2006, and the application will
occur, weather permitting, during October 2006. Should MilestoneTM not be approved
for use on city land in 2007, staff will work with CDOT to determine a single herbicide
that is mutually acceptable for future use.
le. Behavioral displacement of wildlife species
Construction noise may cause wildlife species to avoid the area during periods of active
construction. To lessen the effects of noise on wildlife, the city normally includes noise
restrictions consistent with the city noise ordinance for construction projects of this type.
Construction noise may be a special concern for any nesting migratory birds in the area.
The Migratory Bird Treaty Act (MBTA) protects raptors and other migratory birds.
Unless permitted by regulations, the Act provides that it is unlawful to pursue, hunt, take,
capture or kill; attempt to take, capture or kill; possess, offer to or sell, barter, purchase,
deliver or cause to be shipped, exported, imported, transported, carried or received any
migratory bird, part, nest, egg or product, manufactured or not, subject to limitations in
the Act. In Colorado all birds except for the European starling (Sturm vulgaris), house
35
sparrow (Passer domesticus), and rock dove (Columba Livia) are protected under the
MBTA. A Nest Depredation Permit, issued by the U.S. Fish and Wildlife Service, is
needed to remove, disturb, or destroy an occupied nest. Additionally, the CDOW has
published recommended buffer zones for nesting and breeding raptors in the state.
Compliance with the MBTA requires the following:
While destruction of a nest by itself is not prohibited under the MBTA, nest
destruction that results in the unpermitted take of migratory birds or their eggs is
illegal and fully prosecutable under the MBTA (Migratory Bird Permit
Memorandum, Steve Williams -Director U.S. Fish and Wildlife Service, April I5,
2003). Thus the nest or nest trees cannot be removed or destroyed during the
breeding season (generally March through July).
Take of an active nest site requires obtaining a nest depredation permit from the
Migratory Bird Office of the U.S. Fish and Wildlife Service.
Nests or nest trees that will eventually be removed can be removed during the non-
breeding season to preclude nesting.
• Habitat disturbing activities (such as tree removal, grading, scraping, and grubbing)
should be conducted in the non-breeding season (August through February) to avoid
disturbing (or take) of a migratory bird nest, including ground-nesting species.
The project area was reviewed for migratory bird nests. No nests were observed.
Songbirds were observed during the site visit. The project area contains suitable habitat
for seven migratory bird species of concern.
Great horned owls (Bubo virginianus)are large predatory birds that occur in a wide
variety of habitats, typically including some trees and open areas for hunting rodents and
other prey (Kingery 1998). Great horned owls will nest in a variety of circumstances
including nests constructed by other raptors or magpies, or in tree cavities, or on cliffs.
The project area is suitable habitat for great horned owls, although this species was not
observed.
Golden eagles (Aquila chrysaetos) are protected by the Migratory Bird Treaty Act and
the Bald and Golden Eagle Protection Act. This species nests in a variety of habitats,
most often on cliffs and occasionally in large trees. Golden eagles typically forage over
vast areas in search of prey that includes rabbits, rodents, hares, and carrion (Kingery
1998). Recent bird surveys found golden eagles nesting widely over the western two-
thirds of Colorado with less breeding occumng on the eastern plains (Kingery 1998).
Although this species does occur on the eastern plains, it favors canyon areas to the west
for nesting. No golden eagles currently nest at the project area; however, golden eagles
may forage in the area, especially in winter.
The prairie falcon (Falco mexicanus) is a swift acrobatic falcon that typically nests on
cliff faces in open country below 10,000 feet (Kingery 1998). Migrants and winter
residents occur mostly in grasslands, shrublands, and agricultural areas (Andrews and
Righter 1992). The prairie falcon could occasionally forage on or near the project area,
and the cliffs and rock outcrops would provide potential breeding habitat.
36
The red-tailed hawk (Buteo jamaicensis) inhabits open areas interspersed with patches
of trees or other elevated perch sites that provide a commanding view of the surrounding
terrain in all habitat types (Preston and Beane 1993). The overall abundance ofred-tailed
hawks has increased in recent decades. Red-tailed hawks typically do not nest within 1/3
mile of human habitation, although some members of this species have adapted to
urbanization, and may tolerate human habitation within 200 yards of the nest (Craig
2002). This species is likely to forage at the project area, but no nests large enough to be
ared-tailed hawk nest were observed.
Rough-legged hawks (Buteo lagopus) are fairly common winter residents on the eastern
plains of Colorado (Andrews and Righter 1992). These hawks typically occur in
grasslands, shrublands, agricultural areas, and occasionally in riparian forests. Rough-
legged hawks may occasionally occur at the project area during winter.
Flammulated owls (Otus flammeolus) primarily use ponderosa pine forest habitat and
dense shrubs along small streams. These owls occur between 6,000 and 10,000 feet.
Nesting begins in mid-June, and young are fledged by about the end of August (Kingery
1998). The Boulder County Nature Association (BCNA) has identified the flammulated
owl as a Category 4 species, meaning it has isolated or restricted populations (Hallock
and Jones 1999).
Northern goshawks (Accipiter gentilis) in Colorado primarily inhabit mature coniferous
forests, including ponderosa pine forests along the Colorado Front Range (Kingery
1998). Goshawks are somewhat sensitive to human disturbance, and require large blocks
of forest for foraging and nesting. These hawks hunt for small birds and mammals,
including squirrels, rodents, and hares, under the forest canopy and in open meadows or
brush. Goshawks build large nests, which are sometimes reused (Kingery 1998). The
BCNA has identified the goshawk as a Category 4 and Category 5 species, meaning it has
isolated or restricted populations and also needs additions research on population changes
and habitat specifics of nest site location. The project area may contain appropriate
foraging habitat for the goshawk, but nesting is unlikely due to human disturbance and
relatively young ponderosa pine forest.
An additional migratory bird survey of the project area will be conducted prior to
construction. Any nests or nest trees that will require removal will be removed prior to
the breeding season. If necessary, construction will be scheduled to avoid activity within
recommended buffer zones surrounding any nest trees outside the construction corridor
during the nesting season.
lf. Introduction ofnon-native plant species in the landscape
The general project area is already heavily infested with weeds. Without a
preconstruction weed control program, it is likely that the weed infestation will increase,
since many of these species prefer disturbed ground surfaces. In addition to
preconstnrction weed control, the city will provide for manual weed control in
revegetated areas for three years following the completion of construction to allow
seeded and planted vegetation to become established. Implementation of pre- and post-
37
construction weed control measures and awell-designed revegetation program should
result in long-term improvement of the project area with respect to weeds.
The city also commonly requires that contractors use erosion control materials such as
hay or straw bales that are certified weed-free to avoid introducing new species. Other
standard requirements which will be specified as appropriate may include washing
construction equipment and vehicles when leaving the project area and special handling
of weed infested soils.
lg. Changes to groundwater or surface water runoff
Altematives 2 and 3 for this project will disturb more than one acre of ground surface and
will require a stormwater discharge permit. This permit will be obtained following
completion of project design on the basis of the locations and characteristics ofdisturbed
areas and will include a plan to mitigate any potential negative effects of runoff from the
construction area. It is anticipated that a plan similar to that prepared for Lakewood
Pipeline Phase III construction will be prepared which will include the appropriate use of
water bars, hay bales and sediment settling basins along with requirements concerning
rapid stabilization and restoration of disturbed areas as construction proceeds.
lh. Discharge of sediment to any body of water
Discharge of sediment associated with Alternatives 2 and 3 should be prevented through
the implementation of a good erosion and runoff control as described under (g), above.
2. Loss of mature trees or significant plants
Trees will need to be removed from the construction comdor. Because of poor restoration
efforts in previous construction, there currently exists a mostly treeless corridor which can be
used for a part of the construction corridor. More precise estimates of tree removal
requirements will be made following project design when the locations and sizes of disturbed
areas can be more precisely defined. The project revegetation plan will specify the number,
types and locations of trees to be replanted following the completion of construction.
B. Riparian Areas/Floodplains
1. Encroachment upon the 100-year conveyance or high hazard flood zones
The pipelines included within this project will be buried and will not affect the flood
conveyance of Boulder Creek. During project design, staff will investigate partially or
totally burying the pressure reducing valve (PRV) vault required for the discharge line in
Alternatives 2 and 3. The vault will be designed for submergence and to withstand
damage from debris.
38
2. Disturbance to or fragmentation of a riparian corridor
This project will temporarily disturb areas within the riparian comdor along Boulder
Creek, most of which are already significantly disturbed. The extent of temporary
disturbance will depend on the final project design. The restoration and revegetation plan
for this project will provide for the successful re-creation of any riparian vegetation
disturbed by construction.
Staff anticipates that a municipal wetland permit will be required for this project, since
the PRV vault may be located within 50 Feet of the north bank of Boulder Creek and
some discharge line construction may occur within this zone.
C. Wetlands
No wetlands that meet the U.S. Army Corps of Engineers (Corps) 1987 Delineation
Manual criteria for wetlands were found within the project area. Boulder Creek is
assumed to be a jurisdictional water of the U.S.; therefore, if any impacts to Boulder
Creek are anticipated, a 404 permit from the Corps will be required.
Two wetlands that meet the city of Boulder criteria for wetlands using the 1989
Delineation Manual are present in the project area. The 1989 Delineation Manual
requires only two of the three wetland indicators (Vegetation, Hydrology, and Soils) be
present for a wetland determination. These two wetlands are located along the edges of
Boulder Creek (see Figure 5).
Wetland 1 is located at the eastern end of the project area along Boulder Creek. This
wetland has asedge-horsetail understory and willow/chokecherry shrub layer about 5 to 7
feet tall. About 50 percent of dominant species are hydrophytic. Although the wetland
area is within about 10 horizontal feet of Boulder Creek and about 1 vertical foot of the
water level at the time of the site visit, soils were not moist and neither primary nor
secondary hydrology indicators were present. Soils were low-chroma (Munsell moist
matrix color l OYR 2/1), and were sandy loam in texture. At depths greater than about 10
inches, rock and cobble was present. No mottles were present in the soils. Vegetation
and soils are the two wetland criteria met for this wetland.
The vegetation composition of yvetland 2 is similar to wetland 1. The understory consists
of horsetail, redtop, and yellow sweetclover (Melilotus offcinalis), and the shrub layer
consists of willow, chokecherry, and snowberry. About 50 percent of dominant species
are hydrophytic. Although the wetland area is within about 10 horizontal feet of Boulder
Creek and about 1 vertical foot of the water level at the time of the site visit, soils were
not moist and neither primary nor secondary hydrology indicators were present. Soils
were low-chroma (Munsell moist matrix color lOYR 2/1), and were sandy loam in
texture. At depth greater than about 6 inches, rock and cobble was present. No mottles
were present in the soils. Vegetation and soils are the two wetland criteria met for this
wetland.
These wetlands and associated buffer zones will be avoided to the extent possible in the
project design. if they cannot be completely avoided, temporary disturbance and
restoration will be specified in a municipal wetlands permit application for the project.
39
E. Water Quality
1, Impacts to water quality from any of the following?
la. Excavation
Installation of the proposed discharge line to Boulder Creek and pressure reducing valve
and vault in Alternatives 2 and 3 have the potential to affect water quality due to
excavation in the general vicinity of Boulder Creek. It is anticipated that careful design
of the project and use of best management practices for runoff control during
construction as described in Section A.1 (g) above will prevent the discharge of any
sediment to the creek from excavation areas.
le. Change in Vegetation
There will be short-term disturbance and vegetation removal associated with Alternatives
2 and 3. Implementation of a carefully designed erosion control plan during and after
construction should prevent any potential negative effects to water quality. Revegetation
will occur as previously described.
2. Exposure of Ground Water
Trench excavation within the Boulder Creek floodplain will most likely encounter ground
water and trench dewatering will be required. Trench dewatering will be discussed in a
construction dewatering permitting application for the project. In similar projects,
groundwater has been pumped onto the ground surface for slow absorption in sediment
settling basins. It is assumed that similar measures will be employed here.
There is no known contamination of groundwater in this area.
F. Air Quality
1. Short or long term impacts of air quality (C02 emissions, pollutants)?
la. Short or long term impacts to air quality from mobile sources.
Construction vehicles and equipment will cause short term emissions of exhaust during
construction. Traffic delays required to complete blasting or highway crossing will also
cause temporary emissions of exhaust. These short term effects will be minimized by
using standard city contract requirements concerning vehicle idling and condition in the
construction contract and by minimizing traffic stoppages or delays on Highway 119.
lb. Short or long term impact to air quality from stationary sources.
Altematives 2 and 3 for this project result in increased renewable energy production at
the city's existing Betasso Hydro facility. Increases in renewable energy production
offset the need to generate an equivalent amount of electricity at a fossil fuel fired plant
and therefore results in the reduction of emissions of gases associated with the burning of
fossil fuels. Estimates of reduced emissions for Alternatives 2 and 3 are shown in Table
4.
41
H. Cultural Resources
lc. Impacts to a historic feature of the site
A literature review was conducted through the Colorado Office of Archaeology and
Historic Preservation to determine if known historic features exist in the project area.
Two historic sites, the Boulder Canyon Road and the Boulder Canyon Hydro facilities,
cou-d be affected by the project.
The Boulder Canyon Road (Highway 119) will be crossed by all project construction
alternatives. During project design, the feasibility of boring beneath the highway to
install pipelines will be investigated. While intact, historic portions of the Boulder
Canyon Road have been determined eligible for nomination to the National Register of
Historic Places, it is unlikely that this project will be considered to have an adverse effect
on this historic feature.
The Boulder Canyon Hydroelectric Project, including Bazker Dam and Reservoir, the
Barker Gravity Line, Kossler Reservoir, the Boulder Canyon Penstock and the Boulder
Canyon Hydroelectric Plant, is considered a significant historic site which is eligible for
nomination to the National Register of Historic Places. The Betasso Penstock which
begins at the Boulder Canyon Penstock is of later construction and is not associated with
the historic elements of the site as currently defined. While construction will occur near
historic elements, the historic features themselves will not be changed.
Staff requested State Historic Preservation Officer (SHPO) comments and concurrence
with the assessment that the proposed project will not adversely affect the historic
Boulder Canyon Hydroelectric Project. The SHPO declined to comment stating that its
project review responsibilities and authorities are limited to situations involving federal
funding or authorization.
I. VisualOuality
lb. Effects on the aesthetics of a site open to public view
The existing Betasso Penstock corridor is highly visible from Boulder Canyon and
surrounding areas due to a lack of restoration and revegetation following the original
construction. Alternatives 2 and 3 will involve visible temporary disturbance of this area,
but will also provide the opportunity to restore and revegetate this corridor to lessen the
visual effects. In particular, planting of trees to provide more irregular, feathered corridor
edges and restoration of native understory vegetation will improve the aesthetics of the
site.
J. Safe
2. Site Hazards
Construction sites create safety hazards for both workers and the public. The city uses a
variety of standard contract provisions to ensure the safety and security of its construction
sites. In similar projects staff has also implemented a program of routine communication
with emergency responders to further enhance public and worker safety. When kept
42
informed of the nature, location, and hazards associated with on-going work, first
responders are best able to respond quickly and effectively to any incident on the project.
The existing Orodell Pipeline follows the Link Trail along the boundary of Boulder
County's Betasso Preserve. It may be advisable to close this trail during construction to
prevent entry of bicycles or pedestrians into construction zones. Staff will consult
Boulder County Parks and Open Space concerning the advisability of trail closure.
L. Services
1, Additional need for:
lc. Maintenance of pipes, culverts and manholes
Alternatives 2 and 3 will improve the reliability of Orodell Pipeline and/or Betasso
Penstock and will presumably extend the usable life and reduce the need for maintenance
of these facilities. Increased reliability of these key transmission pipelines will improve
the overall reliability of the city's municipal water supply system.
lh. Transportation improvements/traffic mitigation
All construction alternatives will cause temporary effects to traffic on Highway 119
related to pipeline highway crossing construction and/or blasting close enough to the
roadway to require that traffic is stopped. Maximum delays will be experienced if an
open highway cut is used. CDOT seasonally restricts this type of work to the winter or
early spring to prevent unnecessary impacts to tourist and recreational to traffic during
the summer months. Highway 119 is also heavily used by daily commuters for whom
alternative routes are lacking. Staff will investigate pipeline crossing installation by
boring beneath the road surface to minimize inconvenience to Highway 119 users.
Damage to Highway 119 may result from use of heavy equipment on the roadway or
from the construction activities. CDOT permitting requirements include atwo-year
warranty on the condition of the right-of--way and road surface. The city normally
assigns responsibility for road or right-of--way damage to the construction contractor.
If blasting is required within close proximity to Highway 119, traffic delays will be
necessary. It is likely that blasting that would require traffic stoppage could be
accomplished in a single event.
It is likely that the north shoulder of Highway 119 in the vicinity of the pipeline highway
crossing will be used as a construction staging area for a part of the project. Whenever
workers or vehicles are located adjacent to the highway, warning signs, barricades and
other traffic control measures will be employed. CDOT permitting for this project will
require submittal and approval of a traffic control plan developed in accordance with the
Manual on Uniform Traffic Control Devices.
43
References Cited
ERO Resources Corp., Draft Wetland Delineation Report and Natural Resources Technical
Memo, Orodell Pipeline Rehabilitation Project, Boulder County, Colorado. July 2006.
Miller Ecological Consultants, Inc. Aquatic Resource Effects of Proposed Pipeline.
September 29, 2006.
TCB/AECOM. Final Summary Report, Betasso Water Treatment Plant Pipelines Project.
September 2006.
Turner Collie & Braden (TCB). Pipeline No 3 (Boulder Canyon Hydro to Betasso Water
Treatment Plant) External Condition Assessment. July 25, 2005.
Turner Collie & Braden (TCB). Orodell Pipeline External Condition Assessment. February
I5, 2006.
44
MEMORANDUM
TO: Rick Dulin, Sonya Reiser, ECI
FROM: Lee Rozaklis, Hydrosphere, Hydrosphere Resource Consultants, Inc.
SUBJECT: City of Boulder Hydropower Water Availability
DATE: March 9, 2005
This memo and the accompanying spreadsheets summarize our most recent
work estimating water availability to Boulder's hydropower units.
As before, we utilized the Boulder Watershed Model to simulate the operation of
Boulder's water supply system over a hydrologic study period of 1950-1998.
Using output from the model, we developed spreadsheets to complete the
analysis of specific aspects of hydropower operations that could not be easily
incorporated into the model itself.
Based upon the outcome of our January 31, 2005 meeting with ECI and Carol
Ellinghouse, we have analyzed three scenarios described below in order to
provide a valid basis for economic analysis of alternative courses of action being
contemplated by Boulder regarding raw water facility improvements and
associated hydropower development opportunities.
Scenario 1: Existino Facilities -Normal 63~d Street WTP Operations
This scenario simulates the normal operation of Boulder's water supply system
with existing facilities. Specific assumptions include:
- Municipal treated water demand is set to 25,000 acre-feet per year.
- In meeting its treated water demands, Boulder first uses its direct flow
rights (including its Farmers Ditch rights that divert to Boulder Reservoir),
then its exchange rights, then it delivers water from its 63rd Street WTP
and from its mountain reservoirs.
- Betasso WTP - 45 MGD capacity.
- 63~d Street WTP - 10 MGD capacity. The 63~d Street WTP normally
operates at a minimum level of 5 MGD from November through March
each year as an ongoing drought protection measure. During the
remaining months, the 63`d Street WTP operates up to its capacity to meet
demands not met from direct flow rights and exchange rights. Typically,
the 63~d Street WTP delivers an average of 8.3 MGD during April,
September and October, and an average of 5 MGD during November
City of Boulder Hydropower Water Availability March 9, 2005
Page 2
through March, in order to minimize draw-down of Boulder's mountain
reservoirs during these months.
- Barker gravity line - 43 cfs net capacity after 3% seepage losses
- Lakewood and Silver Lake pipelines - 20 MGD capacity.
- Farmers Ditch to Boulder Reservoir "municipal" conveyance capacity -
12.17 cfs
- Barker Reservoir bypasses a minimum of 5 cfs during May-September
and 4 cfs during October-April.
- Silver Lake Hydro: 3.1 cfs - 31 cfs flow range. Silver Lake Hydro receives
all of Boulder's water supply-related diversions and reservoir releases
taken from North Boulder Creek at the Silver Lake Pipeline headgate, as
well as any additional natural flow in North Boulder Creek, subject to
instream flows below the Silver Lake Pipeline headgate of 4 cfs April-
Octoberand 1.5 cfs November-March. Additional Silver Lake Hydro
diversions not usable by Lakewood Hydro are returned to North Boulder
Creek at the Lakewood reservoir spillway.
- Lakewood Hydro: 3.1 cfs - 31 cfs flow range. Lakewood Hydro receives
all of Boulder's water supply-related diversions and reservoir releases
taken from North Boulder Creek at the Silver Lake Pipeline headgate or
the Lakewood North Boulder Creek and Como Creek Inlets.
- Betasso Hydro: 3.9 cfs - 35 cfs flow range. Betasso Hydro receives all of
Boulder's water supply-related diversions and reservoir releases from
Middle Boulder Creek.
- Boulder Canyon Hydro: 16.6 - 83 cfs flow range. Boulder Canyon Hydro
receives Barker outflows to Middle Boulder Creek subject to remaining
capacity in the Barker Gravity Line after deliveries to the Betasso WTP
and also subject to instream flow bypass targets below Barker of 5 cfs
May-September and 4 cfs October-April. No Barker storage releases are
made to supply Boulder Canyon Hydro. Water used for generation at
Boulder Canyon Hydro returns to Boulder Creek near Orodell.
The results of Scenario 1 are presented in the attached workbook. These results
are suitable as a baseline from which to compare costs and revenues associated
with Scenarios 2, 3 and 4.
We understand that Boulder receives additional hydropower revenue in any
month when the combined generation of its Silver Lake, Lakewood and Betasso
hydro units averages at least 50% of their combined nameplate capacities, which
would occur whenever the monthly flow through these three units averages at
City of Boulder Hydropower Water Availability March 9, 2005
Page 3
least 46.2 cfs. A summary of results for this scenario related to Boulder's
capacity-related hydropower targets is shown in Table 1 at the end of this memo.
Table 1 shows the percent of time the target was achieved in each month, and
the average volumetric shortfall for the years in which the target was not met.
Boulder could choose to meet these shortfalls by releasing water from its
reservoirs, although such releases could reduce the reliability of Boulder's
municipal supply system and could have water rights implications.
As shown in Tablet, with existing facilities and normal 63`d Street WTP
operations, Boulder would meet its capacity targets 100% of the time in June
through August, 96% of the time in May, and 22% of the time in September.
It should be noted that the May capacity shortfalls would occur only in certain
types of wet years (with lower-than-normal downstream demands and greater-
than-normal downstream inflows) when Boulder's reservoirs are in priority to
store all inflows. It is the State Engineer's policy that reservoirs must store all
available in-priority water or else be "paper filled" by the amount bypassed. Once
they are "paper filled", reservoirs cannot physically fill at a later time in the same
year except under free river conditions or by exchange.
Accordingly, in such situations, the Boulder Watershed Model simulates
Boulder's reservoirs as storing all inflows other than those needed to meet
Boulder's treated water demands. In practice, Boulder could bypass sufficient
water while filling its reservoirs to meet its capacity targets. Boulder would have
to carefully examine the water rights implications of such a practice.
The amounts of additional reservoir water that would be needed to consistently
achieve capacity targets in the other shortfall months (September through April)
are significant and would have to be carefully evaluated from the perspective of
risk to the reliability of Boulder's water supply system.
Scenario 2: Existing Facilities -Modified 63`d Street WTP Operations
In order to increase the frequency of meeting its hydropower capacity targets in
April and September, Boulder could reduce deliveries from the 63`d Street WTP
during these months to minimal levels (2 MGD is assumed), and increase its
storage releases from its mountain reservoirs to offset reduced 63`d Street WTP
deliveries. This would result in greater flows through the Silver Lake, Lakewood
and Betasso hydro facilities during these months. In order to compensate for
increased April and September draw-downs of its mountain reservoirs, Boulder
could increase deliveries from the 63`d Street WTP during November through
March such that the 63`d Street WTP's overall delivery volume for September
through April is maintained.
City of Boulder Hydropower Water Availability March 9, 2005
Page 4
Scenario 2 simulates such a modified operation of the 63rd Street WTP. In all
other respects, Scenario 2 is identical to Scenario 1.
The results of Scenario 2 are presented in the attached workbook. A summary of
results for this scenario related to Boulder's capacity-related hydropower targets
is shown in Table 1. As shown in Tablel, modifying the operations of the 63rd
Street WTP would increase the frequency of meeting Boulder's September
capacity targets from 22% to 100% of the time. It would also significantly reduce
the average target shortfall in April (from 1,242 AF/year to 460 AF/year).
Scenario 3: Proposed Facilities Including Tram Hill Discharge Line
Scenario 3 modifies Scenario 2 by assuming the addition of a new 30-inch-
diameter City of Boulder Pipeline No. 3, conversion of the existing 20-inch
Pipeline No. 3 into a discharge line from the Betasso Water Treatment Plant to
Boulder Creek, and a new Hannah Barker hydro facility. Specifics of this
scenario are:
- Anew 30-inch-diameter City of Boulder Pipeline No. 3 would replace the
20-inch line. This would reduce head losses at Betasso Hydro and would
facilitate one-hour hydro unit capacity tests.
- The existing 20-inch line would be converted into a discharge line (the
Tram Hill discharge line from the Betasso WTP to Boulder Creek). This
would allow for increased hydropower generation from additional
diversions from North and Middle Boulder Creeks. The Tram Hill
discharge line is assumed to have a 35 cfs capacity.
- Silver Lake Hydro: 3.1 cfs - 31 cfs flow range. As in Scenario 1, Silver
Lake Hydro receives all of Boulder's water supply-related diversions and
reservoir releases taken from North Boulder Creek at the Silver Lake
Pipeline headgate, as well as any additional natural flow in North Boulder
Creek, subject to instream flows below the Silver Lake Pipeline headgate
of 4 cfs April-October and 1.5 cfs November-March. Additional Silver
Lake Hydro diversions not usable by Lakewood Hydro are returned to
North Boulder Creek at the Lakewood reservoir spillway. Because of the
operational changes to the 63rd Street WTP, the hydropower revenues
from Silver Lake Hydro would be different than Scenario 1.
- Lakewood Hydro is assumed to divert additional flows from North Boulder
Creek, subject to instream flows below the Lakewood North Boulder Creek
Inlet of 5 cfs April-September and 2 cfs October-March. Lakewood
diversions in excess of water supply deliveries to Betasso WTP would
generate hydropower at Lakewood Hydro. Excess Lakewood deliveries
would be returned to Boulder Creek near Orodell via the Tram Hill
discharge line.
City of Boulder Hydropower Water Availability March 9, 2005
Page 5
- Betasso Hydro is assumed to divert additional flows in Middle Boulder
Creek below Barker, but only as needed to help meet caoacity targets,
and subject to instream flows below Barker of 5 cfs May-September and 4
cfs October-April. Water in excess of Betasso WTP deliveries would be
used for hydro generation at Betasso Hydro and would be returned to
Boulder Creek near Orodell via the Tram Hill discharge line.
- Boulder Canyon Hydro: 3.7 - 37 cfs flow range. Boulder Canyon Hydro
receives Barker outflows to Middle Boulder Creek subject to remaining
capacity in the Barker Gravity Line after deliveries to Betasso Hydro and
the Betasso WTP and also subject to instream flow bypass targets below
Barker of 5 cfs May-September and 4 cfs October-April. No Barker
storage releases are made to supply Boulder Canyon Hydro. Water used
for generation at Boulder Canyon Hydro returns to Boulder Creek near
Orodell.
- The production schedule for the 63~d Street WTP is assumed to be
modified as described in Scenario 2, in order to increase April and
September deliveries from Boulder's upper system to the Betasso WTP,
thereby increasing the frequency of meeting capacity targets in these
months.
- During October through March, the 1906 Barker hydropower storage right
was assumed to be used to limit outflows from Barker Reservoir to
Boulder's water supply deliveries to Betasso WTP, plus bypasses required
to satisfy downstream senior direct flow rights, plus any additional
bypasses needed to meet the 4 cfs instream flow target in Middle Boulder
Creek. All other inflows were stored, up to an 800 acre-foot limit. (Note:
this limit was reduced from 1,000 AF in our previous analysis to 800 AF
because it produced a more optimal result in terms of meeting April
capacity targets while minimizing April-May hydropower spills.) This
stored water was then released in April and May, first to meet April
capacity targets, then to generate hydropower at Boulder Canyon Hydro.
- Hannah Barker Hydro: 7.9 cfs minimum flow range, to unlimited maximum
flow range. Anew Hannah Barker Hydro facility is assumed at the base of
Barker Reservoir. Hannah Barker Hydro is assumed to receive all Barker
outflow (including deliveries to the Barker Gravity Line). No maximum flow
limit was assumed for Hannah Barker.
The results of Scenario 3 are also presented in the attached workbook, and in
Table 1 below. Compared to Scenario 2, Boulder's ability to meet its capacity
targets would increase significantly in April (from 0% to 94% of the time), and
slightly in May (from 96% to 98% of the time). Moreover, the average April
shortage-to-target would drop from 460 AF per month to 122 AF per month. The
City of Boulder Hydropower Water Availability March 9, 2005
Page 6
remaining April shortages are very minor and Boulder could easily meet these
shortages by making additional releases from Barker Reservoir.
Scenario 4• Proposed Facilities Includino Tram Hill Hydro
This scenario is the same as Scenario 3 except that the Tram Hill discharge line
would serve a Tram Hill Hydro unit with a 1.74 cfs-to-17.4 cfs flow range. The
Tram Hill discharge line's capacity would therefore be limited to 17.4 cfs.
In terms of hydropower water availability, the results of Scenario 4 are nearly
identical to those of Scenario 3.
Table 1: Summary of Hydropower Revenue Target Operations
Scenario 1: Existing
Facilities, Normal 63rd
Street WTP O erations
Scenario 2: Existing
Facilities, Modified 63rd
Street WTP O erations Scenario 3: Proposed
Facilities (with Tram Hill
discharge pipeline),
Modified 63rd Street
WTP O erations
Scenario 4: Proposed
Facilities (with Tram Hill
Hydro), Modified 63rd
Street WTP O eretions
°/ of Years
Capacity
Tar et Met Average
Shortfall in
Remaining
Years, AF
% of Years
Capacity
Tar et Met Average
Shortfall in
Remaining
Years, AF
% of Years
Capacity
Target Met Average
Shortfall in
Remaining
Years, AF
% of Years
Capacity
Target Met Average
Shortfall in
Remaining
Years, AF
OCt 0% 1359 0% 1294 0% 1182 0% 1192
Nov 0% 1370 0% 1735 0% 1663 0% 1673
Dec 0% 1555 0% 1968 0% 1967 0% 1968
Jan 0% 1647 0% 2065 0% 2063 0% 2063
Feb 0% 1351 0% 1745 0% 1745 0% 1745
Mar 0% 1514 0% 1909 0% 1909 0% 1909
Apr 0% 1242 0% 460 94% 122 92% 98
Ma 96% 160 96% 160 98% 213 98% 213
Jun 100% 0 100% 0 100% 0 100% 0
Jul 100% 0 100% 0 100% 0 100% 0
Au 100% 0 100% 0 100% 0 100% 0
Sep 22% 379 100% 0 100% 0 100% 0