10-16-16 WRAB Complete PacketWATER RESOURCES ADVISORY BOARD MEETING
MEETING DATE: Monday, 16 October 2016
MEETING TIME: 6:30 p.m.
MEETING LOCATION: Municipal Services Center, 5050 Pearl St., Boulder, CO 80301
Agenda Highlights:
4:00-6:30p.m. Open House – Bear Canyon Creek Flood Mitigation Study
Agenda
1. Call to Order (6:30 p.m.)
2. Minutes (6:31 p.m.)
3. *Public Comment (6:35 p.m.)
4. *Public Hearing and Consideration of a Recommendation to City Council Regarding the Bear
Canyon Creek Flood Mitigation Study (6:45 p.m.)
5. Information Item – Utility Rate Study Next Steps (7:30 p.m.)
6. Matters from the Board (8:00 p.m.)
7. Matters from Staff (8:10 p.m.)
8. Discussion of Future Schedule (8:15 p.m.)
9. Adjourn (8:20p.m.)
Information Packet
Information Item – 2016 Water Efficiency Plan Update
* Public Comment Item
Agenda item times are approximate.
Information:
Please contact the WRAB Secretary email group at:
WRABSecretary@bouldercolorado.gov
Packets are available on-line at: http://www.bouldercolorado.gov – A to Z, Water
Resources Advisory Board (WRAB), Next Water Resources Advisory Board Meeting
WRAB Minutes
19 September 2016
Page No. 1
CITY OF BOULDER, COLORADO
BOARDS AND COMMISSIONS MEETING MINUTES
Name of Board / Commission: Water Resources Advisory Board
Date of Meeting: 19 September 2016
Contact Information of Person Preparing Minutes: Rene Lopez 303-413-7149
Board Members Present: Lesley Smith, Kirk Vincent, Mark Squillace, Kate Ryan
Board Members Absent: Dan Johnson
Staff Present: Jeff Arthur, Director of Public Works for Utilities
Bob Harberg, Principle Engineer
Ken Baird, Utilities Financial Manager
Eric Ameigh, Project Coordinator for Public Works
Russ Sands, Water Sustainability and Outreach
Rene Lopez, Board Secretary
Consultants Present: Silvia Pettem
Meeting Type: Regular
Agenda Item 1 – Call to Order [6:00 p.m.]
Agenda Item 2 – Swearing in New Board Member [6:00 p.m.]
Agenda Item 3 – Approval of the 15 August 2016 Meeting Minutes [6:02 p.m.]
Motion to approve minutes from 15 August 2016 as amended.
Moved by: Smith Seconded by: Vincent
Vote: 3:0; Kate Ryan ineligible to vote
Agenda Item 4– Public Participation and Comment [6:05 p.m.]
Public Comment:
Carl Norby: Frasier Meadows neighborhood impacted from the 2013 flood. Would recommend the
acceptance of the Bear Creek Mitigation Plan by the board .
Cory Robinson – Inca and Baseline property owner – Here to support Carl Norby and express support
for the Bear Creek Mitigation Plan
Agenda Item 5– Presentation by Silvia Pettem- Boulder’s Flood History [6:10 p.m.]
Agenda Item 6 – Information Item – Update on Rate Study [6:47 p.m.]
Ken Baird, Eric Ameigh presented this item.
Executive Summary from the Packet Materials:
The purpose of this item is to follow up on the August 2016 WRAB discussion related to the Utility
Rate Study Phase 1 analysis. Through that discussion, WRAB provided feedback related to Phase 1
findings. This included generally affirming the key findings related to each of the three utility rate
structures. Areas of discussion included Commercial, Industrial, Institutional (CII) water budgets, the
residential indoor water budget allocation, the fixed -service charge in the wastewater fee, and alternative
calculations for the stormwater/flood management fee. WRAB’s feedback generally reflected consensus
around which options to study for the key issues in the wastewater and stormwater/flood management
rate structures. As such, staff is prepared to seek confirmation of support for studying options related to
those issues. However, issues in the water utility led to significant conversation and some questions
remain as time was limited for the August discussion. Staff is seeking additional feedback on key water
issues at the September meeting. Confirmation of support for studying alternatives for the water utility
issues may take place in October, depending on the need for additional discussion and clarification.
WRAB Discussion Included:
Comments requesting clarification about fixed expenses
Discussions on customer usage trends
Comments regarding Wastewater revenue from Commercial AMU customers
Comments regarding accuracy of water budgets
Discussions regarding setting the residential indoor allocation budget
Comments regarding single family vs multifamily
Alternative rate structures proposed
WRAB Minutes
19 September 2016
Page No. 2
Alternative graphics for billing statement for visual representation of water use
Agenda Item 7 - Matters from Board: [8:25 p.m.]
Smith
o BVCP joint board meeting update
o South Boulder Creek Mitigation Plan open house
Vincent
o Eco district meeting update
Agenda Item 8 – Matters from Staff: [8:30 p.m.]
Information Items
Betasso roof update
Civic area update
Agenda Item 9 – Future Schedule [8:34 p.m.]
Skunk, Bluebell, Kings Gulch item delayed
Next month’s items
Information memos for next month
Revenue options presentation
Tours at Betasso Water Treatment facility and the Wastewater treatment facility
Retreat dates
Adjournment [8:41p.m.]
There being no further business to come before the Board at this time, by motion regularly adopted, t he
meeting was adjourned at 8:41 p.m.
Motion to adjourn by: Smith Seconded by: Vincent
Motion Passes 4:0
Date, Time, and Location of Next Meeting:
The next WRAB meeting will be Monday, October 16th 2016 at 6:00 p.m., at the City's Municipal
Services Center, 5050 East Pearl St., Boulder, CO 80301
APPROVED BY: ATTESTED BY:
_______________________________ __________________________________
Board Chair Board Secretary
_____________________________ ___________________________________
Date Date
An audio recording of the full meeting for which these minutes are a summary, is available on the Water
Resources Advisory Board web page.
https://bouldercolorado.gov/boards-commissions/water-resources-advisory-board-next-meeting-agenda-and-packet
C I T Y O F B O U L D E R
WATER RESOURCES ADVISORY BOARD
AGENDA ITEM
MEETING DATE: October 17, 2016
AGENDA TITLE: Public Hearing and consideration of a recommendation to City
Council regarding the Bear Canyon Creek Flood Mitigation Plan
PRESENTERS:
Jeff Arthur, Director of Public Works for Utilities
Annie Noble, Acting Principal Engineer for Flood and Greenways
Christin Shepherd, Flood and Greenways Engineer
EXECUTIVE SUMMARY:
The purpose of this memorandum is to present the final Bear Canyon Creek Flood
Mitigation Plan (Attachment A) for the WRAB’s consideration, input and
recommendation to City Council.
In 2014, the city retained Amec Foster Wheeler to evaluate potential improvements along
Bear Canyon Creek. Over time, flood improvements have been made at various locations
along the drainageway, but the September 2013 flood highlighted areas of hydraulic
limitation that prompted the public to request additional flood mitigation.
Recommendations were developed, analyzed and presented to the public and the WRAB
throughout this study. Feedback and comments were collected and incorporated into the
final flood mitigation plan where feasible.
The final recommended plan includes a combination of maintenance and capital
improvements that yield the greatest reduction in flood risk. In general, the recommended
improvements include increased capacity in 13 culverts, channel grading and widening,
channel maintenance including sediment and debris removal, and reconfiguring three
stormwater outfalls. The recommended improvements are detailed in the table in the
Analysis section of this memo and shown on maps in Appendix G of Attachment A.
A Benefit Cost Analysis (BCA) was also performed on the recommended improvements
and a Benefit Cost Ratio (BCR) of 0.02 was calculated. Although the BCR was low, the
recommended improvements result in other benefits including: decreased property
damage, increased emergency access during major storm events, and improved safety for
multi-use path users.
Agenda Item 4 Page # 1
STAFF RECOMMENDATION:
Staff requests the Water Resources Advisory Board’s consideration of this matter and
action in the form of the following motion:
Motion to recommend the Bear Canyon Creek Flood Mitigation Plan be recommended
to City Council for acceptance.
BOARD AND PUBLIC FEEDBACK
Information items providing status updates of the Bear Canyon Creek Flood Mitigation
Plan were submitted to the WRAB in April and November of 2015, and June of 2016.
There was one open house in 2014, two open houses in 2015 and an open house was held
prior to the WRAB meeting on June 20, 2016. An additional open house was held prior to
the October 17, 2016 WRAB meeting to display the final recommended improvements.
Notification postcards were mailed to property owners in the study area, emails were sent
to parents of children attending elementary schools in the study area, and a project web
site was developed to provide information. The project website also contains a comment
collection tool that has received fifty comments.
Most public comments indicate support for the recommended improvements. General
themes that were raised are listed and addressed in Attachment B.
BACKGROUND
Since initial development, Bear Canyon Creek has undergone numerous improvements
and continues to benefit from good maintenance within the improved reaches. The
September 2013 flood brought to light some key issues which contributed to property
damage and safety concerns. In general, problems stemmed from areas of hydraulic
limitation, in which the creek experienced limited conveyance capabilities, debris
blockage or lack of effective flow return zones. These pinch points are illustrated on page
five of Attachment A.
After the 2013 flood, the community expressed a strong desire for flood mitigation
improvements along Bear Canyon Creek. In 2014, Amec Foster Wheeler was selected as
the engineering consultant to develop flood mitigation alternatives and mitigation plan. In
order to fully analyze flows and potential improvements in the area of Bear Canyon
Creek, a complete model of the entire drainageway was needed. A Best Available
Information model was created and detailed descriptions of the data used and model
development begin on page seven of Attachment A. Initially, the mitigation alternatives
focused on three distinct areas (illustrated in Attachment C) based on performance
concerns during the 2013 flooding event:
Reach 1: City Limits to Lehigh Street
Reach 2: Lehigh Street to Broadway
Reach 3: Moorhead Avenue to Baseline Road
Preliminary hydraulic model results indicated the need to expand the study area to
evaluate the impacts of the proposed improvements on downstream areas not originally
Agenda Item 4 Page # 2
included in the study. The scope of analysis was expanded to include Broadway to
Moorhead Avenue and Baseline Road to Wellman Ditch. Please see page 11 of
Attachment A for a map of the expanded study area.
Staff and Amec Foster Wheeler then analyzed two alternatives, a maintenance and a
capital improvement alternative to accommodate the 100-year storm. The maintenance
alternative analyzed sediment and debris removal within all culverts, invasive species
removal at various locations along the channel and improving culvert inlet/outlet
conditions by grading and clearing. The capital improvement alternative proposes
increased culvert and channel capacity to pass the 100-year storm event. The two
alternatives concluded that neither maintaining nor upsizing culverts alone is enough to
mitigate risk.
ANALYSIS
The recommended improvements are a combination of the maintenance and capital
improvement alternatives and include sediment and debris removal, channel grading and
increased culvert capacity. A map outlining the final recommended improvements can be
found in Appendix G of Attachment A. The final recommended improvements and their
associated costs are described in the table on the following page.
Amec Foster Wheeler performed a Benefit Cost Analysis (BCA) and calculated a Benefit
Cost Ratio (BCR) of 0.02 for the final recommended improvements. A BCR is the ratio
of benefits, which are the monetary value of damages prevented due to mitigation
implementation, relative to the cost to construct those mitigation measures. It is not
uncommon for flood improvement projects to have a BCR of less than 1.0 because of the
higher cost of capital improvements in an urban environment compared to the relatively
lower cost to reconstruct residential structures. Additionally, in this study, the structures
removed from risk primarily experience shallow flooding, which results in a lower
benefit value.
The Best Available Information Model highlights areas of flood risk not previously
identified in the current 100-year floodplain. Where the current 100-year floodplain
identifies approximately 35 structures within its bounds, the Best Available Information
Model identifies 194 structures that would potentially sustain damage, the majority of
which are located in the area between Broadway and Moorhead Avenue. Please see
Attachment D for a comparison of the floodplain boundaries.
The recommended improvements would reduce the number of potentially damaged
primary structures from 194 to 154. The BCA for this study only accounts for losses
avoided to residential structures and did not quantify other social and environmental
benefits such as emergency access during a storm event, safer routes to schools, reduced
flood insurance premiums, or improved habitat and vegetation. Amec Foster Wheeler’s
BCA calculations can be found in Appendix H of Attachment A.
Agenda Item 4 Page # 3
Bear Canyon Creek Recommended Flood Mitigation Improvements
Reach Location Recommendation Estimated Cost
Reach
1
Wildwood Road Remove sediment in culvert, including gravel bars
and vegetation blocking inlet and outlet
*work completed
by UDFCD
Wildwood Road Grade channel and widen floodplain from Wildwood
Road to Ithaca Drive $467,000
Ithaca Drive
Remove steel culvert and grade channel in
conjunction with stormwater improvement project at
Ithaca Drive
$47,000
Reach
2A
Lehigh Street Increase culvert size to 7.5ft x 28ft concrete box $1,454,000
Table Mesa Drive
Remove sediment in culverts at Ithaca Drive, Yale
Road, Gillaspie Drive and Stanford Avenue including
gravel bars and vegetation blocking inlet and outlet
$25,000 (each)
Stanford Avenue Increase channel capacity from Stanford Avenue to
Harvard Lane $307,000
Harvard Lane Increase culvert size to (2) 7.5ft x 10ft concrete boxes $711,000
Reach
2B
Broadway Modify inlet conditions to increase capacity $67,500
Broadway Sediment and debris removal from Broadway to
Martin Drive $1,057,000
Martin Drive Continue good maintenance -
Reach
3A
Moorhead Avenue Continue good maintenance -
US 36
Increase culvert size to (2) 8.5ft x 14ft concrete boxes
and reconfigure pedestrian separator wall in
underpass and grade multi-use path and channel
downstream to improve the inlet and outlet condition
$950,000
US 36 to CDOT right
of way
Increase channel capacity and reconfigure multi-use
path $30,600
University of Colorado Increase channel capacity in conjunction with CU
Master Plan $1,584,000
Upstream of Church Increase channel capacity $56,000
Saint Andrew Church Replace culverts with 40ft driveway bridge $493,000
Downstream of Church Increase channel capacity $52,000
Reach
3B
Baseline Road Increase culvert size to (2) 7.5ft x 28ft concrete box $2,730,000
Gilpin Drive Increase channel capacity near Gilpin Drive $102,000
Gilpin Drive Increase culvert size to (2) 8ft x 20ft concrete boxes $785,000
Mohawk Drive Continue good maintenance -
TOTAL $11,000,00
The Gilpin Drive and Baseline Road box culverts are the key pinch points in the
drainageway. Without upsizing these culverts, improvements upstream of Baseline Road
will create negative impacts downstream of Gilpin Drive. Recommended phasing for
improvements is shown on page 17 of Attachment A. Generally, improvements go from
Agenda Item 4 Page # 4
downstream to upstream in accordance with engineering best practices. However, there
are some recommended improvements that can be constructed out of sequence with no
negative downstream impacts. These projects include; sediment removal at the Wildwood
Culvert, removal of the Ithaca Drive steel culvert and sediment and debris removal
throughout the drainageway.
When prioritizing and budgeting flood mitigation projects throughout the city the benefits
previously mentioned should be taken into account in addition to the BCR. The city’s
flood management program is comprised of Boulder Creek and fourteen major
drainageways, where over $160M of flood mitigation improvements have been identified
city wide. Based on current funding levels, it is anticipated that it will require more than
80 years to complete these projects. In the Stormwater and Flood Management Utility,
the majority of the project funding is prioritized by life safety (high hazard) and critical
facility (vulnerable population) hazard mitigation issues but other factors apply, such as:
Flood emergency response capability
Property damage mitigation
Collaboration with other Greenways Program Objectives
Potential for operation and maintenance cost savings
Accommodating new growth and development
Opportunities to leverage outside funding
The current six-year Capital Improvements Program (CIP) includes approximately
$500,000 for Bear Canyon Creek.
NEXT STEPS:
Next steps include:
If recommended by the WRAB, the final Bear Canyon Creek Flood Mitigation
Plan will be presented to City Council for acceptance.
Once accepted by City Council, recommended improvements in the Bear Canyon
Creek Flood Mitigation Plan will be scheduled into the CIP as funding is
available.
ATTACHMENTS
Attachment A: Bear Canyon Creek Flood Mitigation Plan
Attachment B: Public Comment General Themes and Responses
Attachment C: Initial Scope of Flood Mitigation Analysis
Attachment D: Existing Conditions FLO-2D and Current Floodplain
Agenda Item 4 Page # 5
BEAR CANYON CREEK FLOOD MITIGATION PLAN Project SponsorsOctober 17, 2016Attachment A: Bear Creek MItigation Plan
BEAR CANYON CREEK FLOOD MITIGATION PLAN 1 CONTENTS Executive Summary .......................................................................................................................................................... 2 Purpose and Objective .................................................................................................................................................. 2 Study Area & Project Need ........................................................................................................................................... 2 Alternatives Analysis .................................................................................................................................................... 2 Recommended Improvements....................................................................................................................................... 3 Next Steps & Phasing ................................................................................................................................................... 3 Section 1: Introduction ...................................................................................................................................................... 4 Study Area Description ................................................................................................................................................. 4 Previous Studies, Plans & Reports ................................................................................................................................ 4 Previously Completed Projects ..................................................................................................................................... 4 Flood History ................................................................................................................................................................ 4 Additional Data Collection ........................................................................................................................................... 5 Public Involvement ....................................................................................................................................................... 6 Section 2: Creation of the Best Available Information Model ......................................................................................... 7 Updating Hydrologic Data ............................................................................................................................................ 7 Updating Hydraulic Data .............................................................................................................................................. 8 Section 3: Alternative Analysis......................................................................................................................................... 9 Maintenance Alternative ............................................................................................................................................... 9 Capital Improvement Alternative .................................................................................................................................. 9 Section 4: Recommended Improvements ....................................................................................................................... 10 Development ............................................................................................................................................................... 10 Resulting Floodplain & Benefits ................................................................................................................................. 10 Benefit Cost Analysis ................................................................................................................................................. 10 Recommended Improvements by Study Reach .......................................................................................................... 11 Reach 1: Upstream City Limits to Upstream of Lehigh Street ............................................................................... 12 Reach 2A: Lehigh Street Culvert to Upstream of Broadway .................................................................................. 13 Reach 2B: Broadway to Upstream of Moorhead Avenue ....................................................................................... 14 Reach 3A: Moorhead Avenue to Upstream of Baseline Road ................................................................................ 15 Reach 3B: Baseline Road to Upstream of Foothills Parkway ................................................................................. 16 Section 5: Phasing & Next Steps .................................................................................................................................... 17 Project Phasing ............................................................................................................................................................ 17 Vegetation Management & Maintenance Plan ........................................................................................................... 17 Future Funding ............................................................................................................................................................ 17 Mitigation Planning & Climate Change ...................................................................................................................... 18 Section 6: References & Acknowledgements ................................................................................................................. 19 References ................................................................................................................................................................... 19 Acknowledgements ..................................................................................................................................................... 19 TABLES AND FIGURES Table 1: Summary of Recommended Improvements ....................................................................................................... 3 Table 2: Manning's n-values ............................................................................................................................................. 8 Table 3: Recommended Improvements by Reach .......................................................................................................... 10 Table 4: Recommended Improvements Phasing Plan .................................................................................................... 17 Figure 1: Study Area & 100-year Floodplain ................................................................................................................... 2 Figure 2: Summary of Recommended Improvements Map .............................................................................................. 3 Figure 3: Pinch Point Locations ........................................................................................................................................ 5 Figure 4:Flood Insurance Study Design Point Changes ................................................................................................... 7 Figure 5: FLO-2D Model Output Compared to 2013 Flood Extents ................................................................................ 8 Figure 6: Study Reaches ................................................................................................................................................. 11 APPENDICES Appendix A: Bear Canyon Creek Watershed Information Appendix B: Wetland Evaluations Appendix C: Relevant Planning Document Excerpts Appendix D: Environmental Report & Habitat Assessment Appendix E: Culvert Blockages Appendix F: Alternative Analysis Data Appendix G: Recommended Improvements Data Appendix H: Benefit Cost Analysis Attachment A: Bear Creek MItigation Plan
BEAR CANYON CREEK FLOOD MITIGATION PLAN 2 EXECUTIVE SUMMARY PURPOSE AND OBJECTIVE The purpose of this study is to analyze the existing conditions within the Bear Canyon Creek floodplain, develop drainageway planning concepts to mitigate flood damages and prepare recommended flood mitigation improvements including prioritization and costs. This plan will also be beneficial in completing grant applications and securing funding for future projects. STUDY AREA & PROJECT NEED The study area and current 100-year floodplain for Bear Canyon Creek, shown on the figure at right, extends just west of city limits downstream to Foothills Parkway. The September 2013 flood brought to light some key issues which contributed to property damage and safety concerns. In general, problems stemmed from areas of hydraulic limitation, in which the creek experienced limited conveyance capabilities, debris blockage or lack of effective flow return zones. Following the 2013 flood, the community expressed a strong desire for flood mitigation improvements along Bear Canyon Creek. Amec Foster Wheeler was selected as the engineering consultant team to help develop flood mitigation alternatives and this mitigation plan. ALTERNATIVES ANALYSIS Amec Foster Wheeler analyzed Bear Canyon Creek with several modeling techniques and mitigation opportunities were identified. Improvements were analyzed based on a bookend approach: maintenance measures, such as sediment and debris removal, were evaluated and compared to capital improvements, which included increasing culvert capacities to accommodate the 100-year storm. The final recommended improvements are a combination of maintenance and capital improvements that create the greatest reduction in flood risk. Amec Foster Wheeler performed a Benefit Cost Analysis (BCA) and calculated a Benefit Cost Ratio (BCR) of 0.02 for the final recommended improvements. It is not uncommon for flood improvement projects to have a BCR of less than 1.0 because the BCR is calculated using financial factors of losses avoided and costs to construct. The higher costs of capital improvements compared to the relatively lower costs to reconstruct residential structures generally yields a lower BCR. FEMA’s BCA tool does not completely quantify other social and environmental benefits such as emergency access during a storm event, safer routes to schools, public desire for project completion, reduced flood insurance premiums, water quality, tree canopy, improved habitat and vegetation. However, these other benefits should be taken into account when prioritizing and budgeting flood mitigation projects throughout the city. Figure 1: Study Area & 100-year Floodplain Attachment A: Bear Creek MItigation Plan
BEAR CANYON CREEK FLOOD MITIGATION PLAN 3 RECOMMENDED IMPROVEMENTS Amec Foster Wheeler and city staff created final recommended improvements that include sediment and debris removal, channel grading and widening, stormwater reconfiguration and increased culvert capacity. The recommended improvements are described in the table below and illustrated on the figure at right: Table 1: Summary of Recommended Improvements Recommendation Cost Culvert Improvements: Increase culvert capacity at multiple locations along drainageway. $7,200,000 Channel Improvements: Increase channel capacity to convey the 100-year storm and accommodate new culverts and bridges. $3,800,000 Channel Maintenance: Remove sediment and debris, clear and grade culvert inlet/outlet Incorporate into city maintenance plan Reconfigure Stormwater Outfall: Re-align stormwater outfalls at three locations along drainageway TBD Total: $11,000,000 NEXT STEPS & PHASING Some recommended improvements will undergo public process during the design phase which can include; a Community and Environmental Assessment Process (CEAP), input and recommendation from the Water Resources Advisory Board (WRAB), input and recommendation from other advisory boards such as Planning Board, and City Council. Once design is fully approved, funding for construction can be pursued. There may be opportunity for collaborative funding efforts with transportation projects, the University of Colorado or the Federal Emergency Management Agency (FEMA). Other recommended improvements can be completed as major maintenance activities, removing rather than replacing infrastructure. These projects include the removal of the Ithaca Drive steel culvert or sediment clearing in the Wildwood Road culvert. The maintenance and vegetation removal schedules for Bear Canyon Creek can also be updated to clear sediment and debris, remove weeds, mow grass and cut trees that threaten to fall into the channel and block flow with greater frequency. The city is currently working on an asset management system to better plan and execute maintenance activities in all the drainageways including Bear Canyon Creek. It is important to note that the improvements downstream of Baseline Road have priority for design and construction. Gilpin Drive is the main pinch point for the entire downstream section. Without increasing capacity at this culvert, any upstream improvements will cause negative downstream impacts, particularly near Mohawk Drive. Figure 2: Summary of Recommended Improvements Map Attachment A: Bear Creek MItigation Plan
BEAR CANYON CREEK FLOOD MITIGATION PLAN 4 SECTION 1: INTRODUCTION STUDY AREA DESCRIPTION Bear Canyon Creek originates in City of Boulder Open Space. From the city limits at Bear Creek Trail to its confluence with Boulder Creek, Bear Canyon Creek is approximately 6.3 miles in length and ranges in elevation from approximately 6170 feet to 5235 feet USGS. The watershed associated with this creek is approximately 5.3 square miles. West of city limits, the upper part of the watershed is covered with a variety of rock outcroppings and thick soils on bedrock. These sandy composition soils contribute to sediment deposition downstream. Within city limits, the creek generally flows to the northeast through developed neighborhoods, crossing both public and private land. Historically, the area surrounding Bear Canyon Creek within city limits was used for farming and agriculture. These areas have experienced natural springs and shallow groundwater. During the late 1950’s and early 1960’s, the area was developed for residential use. This urban environment lends itself to increased runoff and higher flow velocities. Although much of Bear Canyon Creek has undergone mitigation improvements to pass 100-year storm events. The development surrounding the drainageway contributes to higher cost for improvements and a lower Benefit Cost Ratio. Please see Appendix A for more details on soils, land use, and notable landmarks for the Bear Canyon Creek watershed. PREVIOUS STUDIES, PLANS & REPORTS 1970: Wright-McLaughlin Engineers prepared a Major Drainageway Planning document for South Boulder. This document recommended channel reconstruction primarily from Broadway to Wellman Canal, most of which has been constructed 1985: A Master Plan document for Boulder Creek Tributaries was prepared and outlined culvert and stream capacity improvement locations that are included in and expanded upon in this mitigation plan. 1985: A Flood Insurance Study (FIS) was conducted that produced detailed hydrologic and hydraulic information for the City of Boulder and its vicinity. 1987: Greenhorne & O’Mara, Inc. developed a final Hydrologic Analysis Report that developed a Flood Hazard Area Delineation (FHAD), or the effective 100-year floodplain for Bear Canyon Creek. 2004: a functional evaluation of individual wetlands was completed for the City of Boulder. According to the evaluation, the wetlands upstream of Lehigh Street are characterized as relatively high quality riparian corridor. Downstream of Lehigh Street to the confluence with Boulder Creek, the wetlands are described as having lower functional value. Wetland evaluation summaries are included in Appendix B. The Boulder Valley Comprehensive Plan, the Comprehensive Flood and Stormwater Utility Master Plan, the Urban Drainage and Flood Control District (UDFCD) Drainage Criteria Manual and the Greenways Master Plan all contain policies related to floodplain preservation, development, and mitigation and guide flood mitigation master planning. Relevant excerpts can be found in Appendix C. PREVIOUSLY COMPLETED PROJECTS Several improvements have been constructed on Bear Canyon Creek including: 1991: Construction of an underpass at Baseline Road with trail connections to the CU main campus. 1992: Trail reconstruction between the Wellman Canal and Mohawk Drive. 1993: Trail extension between Mohawk Drive and Gilpin Drive, including riparian habitat widening and restoration, wetland creation, landscaping, the construction of an underpass at Arapahoe Avenue, and a low water crossing downstream of Mohawk Drive. 1995: Construction of an underpass beneath Mohawk Drive. 1996: Construction of flood capacity improvements, trail connections and underpasses beneath Martin Drive and Moorhead Avenue. In cooperation with the UDFCD, additional flood improvements were completed and a pedestrian and bicycle underpass was added at Gilpin Drive. 1998: Modification of Martin Park to provide 100-year flood containment, removing approximately 200 properties from the 100-year floodplain. A pedestrian/bicycle underpass and associated flood improvements were completed at South Broadway. 2000: Construction of a path connection 36th Street to the Bear Creek path. 2003: Completion of improvements to the levee along Bear Canyon Creek on Harrison Drive and capacity improvements along Foothills Parkway in conjunction with the development of the new hospital site at Foothills and Arapahoe. 2004-2006: Plantings on west bank in Martin Park. 2007: Construction of a new bicycle/pedestrian underpass and flood mitigation improvements at Foothills Parkway and Arapahoe Avenue. 2009: City Council accepted a Letter of Map Revision (LOMR) for Bear Canyon Creek from Foothills Parkway to Boulder Creek. The LOMR was prepared to reflect new mapping, an underpass at Arapahoe Avenue, and improvements to the Harrison Avenue Levee. FLOOD HISTORY Bear Canyon Creek, like much of Boulder, is highly susceptible to flash flooding because of its location at the base of the foothills. Significant flooding has occurred over the decades but most recently in September of 2013. During the September 2013 event, the National Oceanic and Atmospheric Association and the National Weather Service reported that precipitation totals in many parts of the Boulder Creek watershed had annual exceedance probabilities of a 1,000-year rainfall event. Wright Water Engineers prepared a “Rainfall-Runoff Analysis for the September 2013 Flood in the City of Boulder, Colorado”, which was publicly released in September of 2014. According to this study, “the rocky soils and shallow bedrock in the Attachment A: Bear Creek MItigation Plan
BEAR CANYON CREEK FLOOD MITIGATION PLAN 5 upper sub-watersheds limit infiltration, and intense periods of rainfall later in the event, when soils were saturated, produced significant runoff and debris flows.” The significant amount of rocks, sediment and debris blocking the culverts along Bear Canyon Creek the extent of flooding in September 2013 was beyond what would be normally mapped for a 25 to 50-year “clear water” flood. To determine runoff during the September 2013 event, Wright Water analyzed the city’s inundation mapping which indicated that runoff during the event was generally contained with the 100-year floodplain boundary, with peak flows approaching 50-year levels at Broadway and Table Mesa Drive and further downstream, near Baseline Road, on the order of 25-year levels. The notable exception was Broadway north of Table Mesa Drive, where flows split to the north, flooding some areas in the Martin Park neighborhood that were not mapped in the 100-year floodplain. It is significant that the Table Mesa Drive channel, which was known to be undersized for major flood events, fared well despite overtopped banks and high flow velocities down Table Mesa Drive. “During the 2013 flood, the Bear Canyon Creek channel and boulder drop structures held up well… several drop structures were damaged and bank erosion exposed a natural gas line; however, Table Mesa Drive remained passable throughout all but the most intense parts of the multi-day flood event” (A September to Remember). Along the creek, many culverts became partially or mostly clogged with rocks, sediment, and debris which forced the floodwaters to leave the stream banks and flow down the streets. The storm sewer system and sanitary sewer systems were also overwhelmed due to the flood waters and elevated groundwater. The 2013 flood highlighted key pinch points that hydraulically limited the flow capacity of the drainageway. These pinch points are illustrated in the figure on the following page and are the main focus of this mitigation plan’s alternative analysis. After the September 2013 flood, the city commissioned a study to analyze the source of and amount of damage caused by the flood. The results are a compilation of data obtained via an online survey and also of claims submitted to FEMA for reimbursement. In the Bear Canyon Creek watershed, it is estimated that the total amount of damages exceeded just over $18,000,000. The primary sources of damage in the floodplain was a result of major drainageway flooding, flooding from local drainage, and sanitary sewer backups. It is estimated that approximately $1.5M in damage was caused in the 100-year floodplain, $3.5M in damage was caused in the 500-year floodplain, and the remainder was outside of the designated floodplains. (Summary Report of Private Property and Resident Flood Impact Survey and Analysis, September 2013 Flood Disaster) ADDITIONAL DATA COLLECTION Elevation data for the study area was taken from 2013 Light Detection and Ranging (LiDAR) data that was sponsored by FEMA and collected after the September 2013 flood event. In addition, survey collected as part of previous hydraulic studies or as-built construction drawings was also incorporated in the analysis. Figure 3: Pinch Point Locations Attachment A: Bear Creek MItigation Plan
BEAR CANYON CREEK FLOOD MITIGATION PLAN 6 In the fall of 2015, Amec Foster Wheeler completed an environmental and habitat assessment of Bear Canyon Creek (Appendix D). The assessment indicates that certain non-native species negatively contribute to the system function within city limits. Specifically, what is commonly known as crack willow: a tree that easily breaks off twigs and branches with an audible crack. These broken twigs and branches readily take root in waterways, causing increased vegetation and debris in the drainageway. In addition, some of the stream banks are incised with exposed roots and are not conducive to plant growth without additional bank stabilization. PUBLIC INVOLVEMENT One open house was held in 2014 and two open houses were held in 2015 to present potential alternatives and to solicit feedback from the public. Information items providing status updates of the Bear Canyon Creek Flood Mitigation Plan were submitted to the Water Resources Advisory Board (WRAB) in April and November of 2015. Comments received at the open house and the WRAB meeting were assimilated and the mitigation plan was further refined based on these comments, where feasible and practical. Recommended improvements were developed by Amec Foster Wheeler based on the feedback from public meetings, project stakeholders, staff input and preliminary discussions with the WRAB. The recommended improvements work to minimize identified flooding issues along Bear Canyon Creek and includes improvements able to accommodate a 100-year storm event. A fourth open house was held on June 20, 2016 to present the recommended improvements to the public. That same evening, a presentation was given to the WRAB. Feedback from the WRAB and the public at these meetings was used for final refinement of the recommended improvements. Attachment A: Bear Creek MItigation Plan
BEAR CANYON CREEK FLOOD MITIGATION PLAN 7 SECTION 2: CREATION OF THE BEST AVAILABLE INFORMATION MODEL A complete hydraulic model for the entire reach of Bear Canyon Creek (from city limits to its confluence with Boulder Creek) did not exist at the beginning of this study. Smaller hydraulic models had been developed for segments of Bear Canyon Creek, but did not seamlessly connect as one cohesive model. In order to fully analyze flows and potential improvements in the area of Bear Canyon Creek, a hydraulic model of the entire drainageway was needed. The city and the UDFCD transferred all available modeling data to Amec Foster Wheeler who developed a “Best Avalable Information” existing conditions model. While refining the Best Available Information model and comparing it to actual inundation areas from 2013, Amec Foster Wheeler and city staff noted the need for further refinement in areas where spill flows occur. During a major storm event, overtopping of Bear Canyon Creek is present at several major crossings along this creek, creating spill flows that become hydraulically disconnected from the main channel, flow overland through streets and neighborhoods and then rejoin the floodplain downstream. It was determined that the city’s current two-dimensional model (FLO-2D) approach to define major flow paths and spill flows should be used. Traditionally, regulatory models are developed in HEC-RAS, which is a one dimensional model that analyzes flow only in the longitudinal direction and represents the terrain in a sequence of cross sections. In two dimensional models, such as FLO-2D, flows are allowed to move in both the longitudinal and lateral directions. FLO-2D is ideal for identifying flow paths that split away from the main channel. UPDATING HYDROLOGIC DATA The FLO-2D output did not reflect spill flow paths observed during the September 2013 flood. Adjustments were made to two hydrological design points (shown in the figure at right): Design Point 402: peak discharge for this design point (1,600cfs) was originally applied at the upstream limit of the FIS, which yielded highly conservative flows upstream of Lehigh Street. In the Best Available Information model, the original design point application points and values were assigned. Design Point 401 was applied at the upstream limits and was assigned the correct flow of Design Point 402 was applied at Table Mesa Drive and Ithaca Drive, and was assigned the correct flow of 1,600cfs. Design Point 402 was applied at Table Mesa Drive and Ithaca Drive, and was assigned the correct flow of 1,600cfs. Design Point 405: peak discharge for this design point (540cfs) was applied near Moorhead Avenue along Bear Canyon Creek and represents of a 240-acre sub-basin near Baseline Road and Dartmouth Avenue. In the Best Available Information model, Design Point 405 was applied at the outlet of its sub-basin. Staff also questioned whether flows from Skunk Creek, located north and west from Bear Canyon Creek, had any effect on Bear Canyon Creek flows. The effective 100-year flood mapping for these two drainageways shows a branch of Skunk Creek that extends into Bear Canyon Creek along US 36 and Figure 4:Flood Insurance Study Design Point Changes Attachment A: Bear Creek MItigation Plan
BEAR CANYON CREEK FLOOD MITIGATION PLAN 8 Moorhead Avenue. The topography in this area, however, creates a high point between the two creeks, indicating that this connection arm is not caused by overflow of either drainageway. The flooding experienced in this area is most likely due to surface runoff from Design Point 405 (mentioned above), located near Dartmouth Avenue. UPDATING HYDRAULIC DATA The 1987 FHAD, which established the original limits of flooding for Bear Canyon Creek, utilized a range of blockage values but did not give any explanation for them. The Lehigh Street and Broadway culverts were set at seventy-five percent, while the crossings along Table Mesa Drive were set at fifty percent, for example. Existing culvert blockages were determined by culvert size and location, but also through several field reconnaissance trips to assess existing culvert conditions. Fifteen of the creek crossings carry traffic, and all were considered to be culverts from a hydraulic perspective. The four pedestrian bridges were considered to be clear spans with minor constrictions caused by their abutments, and were assumed to have no blockage for the purposes of hydraulic modeling. The two low flow crossings, a 60-inch steel pipe installed at Ithaca Drive between Lehigh Street and Wildwood Road and a pair of 18-inch culverts which cross Bear Canyon Creek on the CU Campus north of US 36, were assumed to be completely blocked during a significant event. Also, city staff directed Amec Foster Wheeler to use a minimum blockage of 15% in other culverts throughout the drainageway where feasible. The blockages for the crossings were updated in the Best Available Information model to reflect the conditions identified in the field and was used as the baseline hydraulic condition for this analysis. The assumed existing blockage values compared to the original FHAD blockage values can be found in Appendix E. Manning’s n-values were adjusted based on the surrounding land use and are listed in the table below: Table 2: Manning's n-values Land use Description Manning’s n Value Residential 0.20 Forested 0.10 Forested, Dense Brush 0.09 Forested, Sparse 0.08 Landscaping, Light Brush 0.06 Scattered Brush 0.04 Pasture, no brush, short grass, open space 0.03 Streets 0.013 In general, the FLO-2D model confirmed regulatory model flood extents while identifying spill flows similar to what was observed during the September 2013 storm event. The FLO-2D model also confirmed the areas to focus efforts for the mitigation plan. Figure 5: FLO-2D Model Output Compared to 2013 Flood Extents Attachment A: Bear Creek MItigation Plan
BEAR CANYON CREEK FLOOD MITIGATION PLAN 9 SECTION 3: ALTERNATIVE ANALYSIS City staff and Amec Foster Wheeler analyzed alternatives based on a bookend approach, evaluating the least costly mitigation (maintenance) and the costliest (increase culvert capacity at major intersections to accommodate the 100-year storm). The recommended improvements are a combination of the maintenance and capital improvement alternatives and include sediment and debris removal, channel grading and increased culvert capacity. MAINTENANCE ALTERNATIVE A maintenance alternative was created and input into the FLO-2D model for analysis. Maintenance activities included sediment and debris removal within the culverts and their surrounding channel area as well as vegetative thinning of invasive species to eliminate potential debris generation. The maintenance alternative assumed an initial overhaul of the channel and culverts with recurring annual maintenance at higher blockage locations (such as Lehigh Street) and recurring maintenance based on need in other locations. The city performs an annual inspection of all drainageway infrastructure which collects required culvert maintenance activities and the city’s future asset management software will help coordinate activities with city maintenance teams. The maintenance alternative did not include any structural improvements to the channel such as grading or widening, and did not include any upsized culverts. FLO-2D model output for the maintenance alternative followed the same general flow path as the existing regulatory model run, but resulted in more shallow flooding. A map of the FLO-2D output can be found in Appendix F as well as a summary table, prepared by Amec Foster Wheeler, displaying the existing and maintenance condition culvert blockages. The maintenance alternative does not convey the 100-year storm throughout the channel and key pinch point areas remain. Although maintenance will be a part of the recommended alternative, maintenance alone is not enough to mitigate flood risk. This alternative removes 12 structures from flood risk with the most benefit corresponding to the reach 3B, between Baseline Road and Foothills Parkway as described in the graph on the following page. The maintenance alternative highlighted culverts where upsizing is necessary to mitigate risk. To understand the impacts of increasing culvert capacities, a capital improvements alternative, which included new culverts to pass the 100-year storm event, was created and analyzed. CAPITAL IMPROVEMENT ALTERNATIVE A capital improvement alternative, which increased culvert and channel capacity to pass the 100-year storm event, was created and analyzed. The capital improvement alternative included the previously established maintenance alternative. Each major culvert was isolated for evaluation to determine which improvement areas would provide the most significant positive impact to the remainder of the stream. When all culvert improvements were analyzed together, the total structures removed from risk (22) totaled higher than the maintenance run (12). However, the capital improvement alternative also added 10 structures to the 100-year floodplain in Reach 3B, north of Baseline Road. Originally, Reach 3B was not a part of this mitigation plan. Upon running the 100-year improvement alternative, however, it was discovered that the culvert at Gilpin Drive was a major pinch point and negatively impacted structures downstream. These 10 structures would be added to the flood risk because opening up and expanding culverts upstream allows for higher flows to traverse down the channel. Without corresponding channel improvements and sediment/debris maintenance, or increased capacity at the Gilpin Drive culvert, the flows collect and pool at the low topography located near Pitkin Drive. This model run prompted staff to include Gilpin Drive in the recommended alternative. The final analysis indicated Baseline Road and Gilpin Drive culverts as the primary hydraulic limitation points for Bear Canyon Creek north of US 36. Improvements at these two culverts and surrounding channel area need to be combined with improvements in Reach 3A (between US 36 and Baseline Road) in order to provide a 100-year flood mitigation benefit for the entire drainageway. A map of FLO-2D model output for this alternative can be found in Appendix F. Attachment A: Bear Creek MItigation Plan
BEAR CANYON CREEK FLOOD MITIGATION PLAN 10 SECTION 4: RECOMMENDED IMPROVEMENTS DEVELOPMENT Both the maintenance and capital improvement alternatives concluded that neither maintaining nor upsizing culverts alone is enough to mitigate risk. A combination of these two alternatives was needed. The recommended improvements are a combination of channel grading, debris and sediment removal and increasing culvert capacities. The recommended improvements are based on responding to and rectifying the issues highlighted during the 2013 flood and considers benefits to property, life safety, and cost effectiveness. Most of the recommendations are located on city owned property or right of way, with the exception of the University of Colorado (in Reach 3A). The table at right describes the recommendations and associated costs. A map of these improvements can be found in Appendix G. RESULTING FLOODPLAIN & BENEFITS The recommended alternative improvements were input into FLO-2D and the resulting floodplain depths were analyzed. A figure of the FLO-2D model output results can be found in Appendix G. The Best Available Information Model highlights areas of flood risk not previously identified in the current 100-year floodplain. Where the current 100-year floodplain identifies approximately 35 structures within its bounds, the Best Available Information Model identifies 477 primary structures of which 194 would potentially sustain damage (the majority of which are located in the area between Broadway and Moorhead Avenue). The recommended improvements would reduce the number of primary structures in the Best Available Information Model from 477 to 288 and would reduce the number of potentially damaged primary structures from 194 to 154. Amec Foster Wheeler performed a Benefit Cost Analysis (BCA) utilizing FEMA’s BCA tool. The Best Available Information model output was used for existing conditions and the recommended alternative model output was used for future conditions. The recommended alternative was determined by utilizing a loss analysis spreadsheet, originally developed by FEMA Region VIII and modified by Amec Foster Wheeler to summarize flood impacts associated with multiple structures for input into the BCA tool. The screening level loss analysis allowed for the determination of the alternatives that resulted in the greatest losses avoided. The BCA tool was then utilized to calculate the final benefit cost ratio or BCR. FEMA’s BCA tool compares the difference in the damages from the existing and future conditions (post project) floodplains and compares the costs associated with the improvements needed to lessen impacts to structures. The BCA tool also annualizes the damages from the 50, 100 and 500-year events and incorporates maintenance costs over the useful life of the project, which assumed the FEMA default value of fifty years. This process yields a final BCR. Many flood mitigation projects do not always receive a high BCR, particularly if there is minimal risk to the 50-year or more frequent events, which is generally the case along the Bear Canyon Creek corridor. Structure damage under existing conditions along Bear Canyon Creek is generally associated with shallow flooding, and due to the highly urbanized nature of the drainageway, it was not possible to completely eliminate all residual flood risk, even with the recommended Table 3: Recommended Improvements by Reach Reach Location Recommendation Estimated Cost Reach 1 Wildwood Road Remove sediment in culvert, including gravel bars and vegetation blocking inlet and outlet *work completed by UDFCD Wildwood Road Grade channel and widen floodplain from Wildwood Road to Ithaca Drive $467,000 Ithaca Drive Remove steel culvert and grade channel in conjunction with stormwater improvement project at Ithaca Drive $47,000 Reach 2A Lehigh Street Increase culvert size to 7.5ft x 28ft concrete box $1,454,000 Table Mesa Drive Remove sediment in culverts at Ithaca Drive, Yale Road, Gillaspie Drive and Stanford Avenue including gravel bars and vegetation blocking inlet and outlet $25,000 (each) Stanford Avenue Increase channel capacity from Stanford Avenue to Harvard Lane $307,000 Harvard Lane Increase culvert size to (2) 7.5ft x 10ft concrete boxes $711,000 Reach 2B Broadway Modify inlet conditions to increase capacity $67,500 Broadway Sediment and debris removal from Broadway to Martin Drive $1,057,000 Martin Drive Continue good maintenance ‐ Reach 3A Moorhead Avenue Continue good maintenance ‐ US 36 Increase culvert size to (2) 8.5ft x 14ft concrete boxes and reconfigure pedestrian separator wall in underpass and grade multi-use path and channel downstream to improve the inlet and outlet condition $950,000 US 36 to CDOT right of way Increase channel capacity and reconfigure multi-use path $30,600 University of Colorado Increase channel capacity in conjunction with CU Master Plan $1,584,000 Upstream of Church Increase channel capacity $56,000 Saint Andrew Church Replace culverts with 40ft driveway bridge $493,000 Downstream of Church Increase channel capacity $52,000 Reach 3B Baseline Road Increase culvert size to (2) 7.5ft x 28ft concrete box $2,730,000 Gilpin Drive Increase channel capacity near Gilpin Drive $102,000 Gilpin Drive Increase culvert size to (2) 8ft x 20ft concrete boxes $785,000 Mohawk Drive Continue good maintenance ‐ TOTAL $11,000,00 Attachment A: Bear Creek MItigation Plan
BEAR CANYON CREEK FLOOD MITIGATION PLAN 11 improvements. The higher costs of flood mitigation improvements in an urbanized environment also contributes to the lower BCR. The final BCR for the recommended improvements is 0.02. Reducing losses to residential structures was the primary benefit analyzed; factoring in benefits to city infrastructure, roadways, emergency vehicle access, and life safety could result in a much improved BCR and is a noted limitation of this analysis. While these benefits are not accounted for in the BCA, it should be noted that the recommended alternative provides additional benefits, such as: Safer emergency access on Table Mesa Drive and Broadway during a major storm event, including safer emergency access to Bear Canyon Creek Elementary, Partnership and coordination with CU that allows for greater flood control measures on CU property, Safer multi-use underpass configurations, and Safer access on Baseline Road for emergency vehicles during a major storm event. Amec Foster Wheeler’s flood loss estimation calculations can be found in Appendix H. RECOMMENDED IMPROVEMENTS BY STUDY REACH The drainageway was divided into five reaches described below and illustrated on the figure at right. Reach 1: City Limits to Lehigh Street Reach 2A: Lehigh Street to Broadway Reach 2B: Broadway to Moorhead Avenue Reach 3A: Moorhead Avenue to Baseline Road Reach 3B: Baseline Road to Wellman Ditch Recommended improvements for each reach are detailed in the following pages. A map of all recommended improvements is located in Appendix G. Figure 6: Study ReachesAttachment A: Bear Creek MItigation Plan
BEAR CANYON CREEK FLOOD MITIGATION PLAN 12 REACH 1: UPSTREAM CITY LIMITS TO UPSTREAM OF LEHIGH STREET There are two culverts in Reach 1 located at Wildwood Road and Ithaca Drive. Culvert R1-1: Concrete Box Culvert at Wildwood Road Improvement Size Width (ft) Shape Length (ft) % of 100-year Storm Existing (2) 7’ x 12’ 12 Box 100 74% Maintenance (2) 7’ x 12’ 12 Box 100 100% During the September 2013 flood, the Wildwood Road culvert became almost entirely blocked by sediment. The flood waters pooled upstream of the culvert until they overtopped Wildwood Road. Maintenance of this culvert, including removal of sediment in the culvert, gravel bars and vegetation blocking the inlet and outlet was performed by UDFCD in 2016. Similar maintenance should be repeated every 2 to 5 years. The city owns a 20-foot access easement on the upstream side of the culvert that allows maintenance vehicles access. Culvert R1-2: Steel Pipe Crossing at Ithaca Drive Improvement Size Width (ft) Shape Length (ft) % of 100-year Storm Existing 5’ Diameter 5 Steel Pipe 16 0% Remove Remove steel culvert and grade channel in conjunction with stormwater improvement project at Ithaca Drive 100 100% The existing steel pipe was originally used as a farmer’s crossing over the creek. Today, it acts as a social trail for the community. In major storm events, the steel pipe completely clogs with debris and creates high erosion impacts downstream. After the 2013, flood the steel pipe was cleaned and repaired, but the next heavy rain event in the summer of 2014 eroded the repair. The city owns the property where the culvert is located and there are no access issues. A stormwater reconfiguration project is planned for Ithaca Drive and the outfall located upstream of the steel culvert. The steel culvert removal would be more cost effective and cause less disruption to stream and neighborhood activities if completed in conjunction with the Ithaca Drive stormwater project. Reach 1: Channel Improvements & Stormdrain Reconfiguration Location Improvement Length (ft) % of 100-year Storm Wildwood Road Culvert Grade channel and widen floodplain downstream of culvert 760 100% Bear Condominiums Reconfigure stormdrain n/a n/a Ithaca Drive Reconfigure stormdrain n/a n/a The channel downstream of Wildwood Road is shallow with dense vegetation and trees. Widening the floodplain bench, deepening the low flow channel area, and removing nuisance trees and sediment deposits from the floodplain will greatly increase the channel’s capacity. Stabilizing channel banks, specifically on the south side of the creek, will work to protect property owners in that area. A storm drain at the US National Center for Atmospheric Research (NCAR) property outfalls into the creek opposite of Bear Condominiums, downstream of Wildwood Road, and deposits sediment directly into the channel. The re-alignment of this storm drain, by pointing the outfall parallel to creek flows instead of perpendicular, should be considered during the design phase of these channel improvements. The channel in this area is on city owned property and there are no access issues. Culvert R1-2: Ithaca Drive Steel Pipe Attachment A: Bear Creek MItigation Plan
BEAR CANYON CREEK FLOOD MITIGATION PLAN 13 REACH 2A: LEHIGH STREET CULVERT TO UPSTREAM OF BROADWAY Bear Canyon Creek exits Lehigh Street culvert into the center median of Table Mesa Drive where it passes through numerous culverts until it re-joins the multi-use path and crosses under Broadway. Table Mesa Drive to Lehigh Street is a primary access route for Bear Canyon Creek Elementary School and Mesa Elementary School. Construction of improvements should occur during the summer months so as not to disrupt students’ school commute. Culvert R2-1: Concrete Box Culvert at Lehigh Street Improvement Size Width (ft) Shape Length (ft) % of 100-year Storm Existing (2) 4’ x 8’ 16 Box 191 9% Replace (1) 7.5’ x 28’ 28 Box 191 100% The 4-foot high openings for the Lehigh Street culvert are easily blocked with debris and difficult for maintenance crews to enter. During the September 2013 flood, the Lehigh Street culvert became entirely blocked by sediment and the flood waters overtopped Lehigh Street and Table Mesa Drive. The city owns an access easement upstream of the culvert and right of way downstream for construction and maintenance access. Culvert R2-2 to R2-5: Box Culverts on Table Mesa Drive Improvement Size Width (ft) Shape Length (ft) % of 100-year Storm Existing (2) 4’ x 8’ 16 Box 60 20% Maintenance (2) 4’ x 8’ 16 Box 60 30% From Lehigh Street, Bear Canyon Creek flows north and east along the center of Table Mesa Drive where it passes through four culverts at Ithaca Drive, Yale Road, Gillaspie Drive and Stanford Avenue. These culverts act as roadway crossings over the drainageway and are sized for approximately a 10-year storm event. However, the roadway itself is designed to carry 100-year storm events and conveyed flood waters during the September 2013 flood event. The culverts are located in the median of Table Mesa Drive. There are no access issues. Culvert R2-6: Box Culvert at Harvard Lane Improvement Size Width (ft) Shape Length (ft) % of 100-year Storm Existing (2) 4.5’ x 8’ 16 Box 116 15% Replace (2) 7.5’ x 10’ 20 Box 116 100% The existing culvert at Harvard Lane needs to be replaced with a larger capacity culvert in order to pass a 100-year storm event. During the design phase of this culvert, it is highly recommended to review the inlet and outlet conditions for reconfiguration. The current angle from Table Mesa Drive to the Broadway underpass could be less acute and create a smoother transition with less overtopping at Harvard Lane. The upstream portion of this culvert is on city right of way and the downstream portion is located on city property. There are no access issues. Harvard Lane Existing Culvert Configuration Reach 2A: Channel Improvements Location Improvement Length (ft) % of 100-year Storm Stanford Avenue to Harvard Lane Grade channel and widen floodplain to create better inlet conditions at Harvard Lane culvert. 822 100% Attachment A: Bear Creek MItigation Plan
BEAR CANYON CREEK FLOOD MITIGATION PLAN 14 REACH 2B: BROADWAY TO UPSTREAM OF MOORHEAD AVENUE From Harvard Lane, Bear Canyon Creek passes under Broadway alongside a multi-use path and extends north through Martin Acres Neighborhood and Martin Park. Culvert R2-7: Concrete Underpass at Broadway Improvement Size Width (ft) Shape Length (ft) % of 100-year Storm Existing 7.5’ x 23’ 23 Box 83 58% Reconfigure Reconfigure inlet 23 Box 83 100% Culvert R2‐7: Broadway Underpass In order to pass 100-year storm events at Broadway, an additional foot of rise is required in the culvert. This additional rise can be acquired by modifying the existing wingwalls and should be analyzed in greater detail at the time of design. The culvert in located on city owned property and there are no access issues. Culvert R2-8: Box Culvert at Martin Drive Improvement Size Width (ft) Shape Length (ft) % of 100-year Storm Existing 7.5’ x 24’ multi-use underpass 6.5’ x 7.5’ channel 31.5 Box 62 81% No Improvement The underpass at Martin Drive was constructed in 1996 and has held up well in previous large-scale storm events such as September 2013. No capacity increases are recommended for this culvert. However, the roadway at Martin Drive directly above the underpass should be noted as having a low topographic point at approximately Martin Drive and 35th Street. Surface nuisance drainage flows away from the creek and the street could be re-graded to direct flows back towards the creek and off of street surfaces. Reach 2B: Channel Improvements Location Improvement Length (ft) % of 100-year Storm Broadway to Dartmouth Avenue Remove sediment and debris, channel mowing, boulder edging and channel modification 1942 100% Culvert R2-8: Martin Drive Attachment A: Bear Creek MItigation Plan
BEAR CANYON CREEK FLOOD MITIGATION PLAN 15 REACH 3A: MOORHEAD AVENUE TO UPSTREAM OF BASELINE ROAD From Moorhead Avenue, Bear Canyon Creek passes under US 36 and extends north through University of Colorado property towards Baseline Road. Culvert R3-1: Concrete Underpass at Moorhead Avenue Improvement Size Width (ft) Shape Length (ft) % of 100-year Storm Existing 7.5’ x 24’ 24 Box 120 61% No Improvement The underpass at Moorhead Avenue has performed well during previous storm events. The Best Available Information model indicates that if downstream improvements are in place, any upstream improvements will not create additional damage at Moorhead Avenue or downstream. The culvert is located on city owned property and there are no access issues. No improvements are recommended at this time. Culvert R3-2: Concrete Underpass at US 36 Improvement Size Width (ft) Shape Length (ft) % of 100-year Storm Existing (2) 7’ x 14’ 28 Box 112 22% Increase capacity and remove pedestrian separator wall (2) 8.5’ x 14’ 28 Box 112 100% At the US 36 culvert, the pedestrian underpass and drainageway are separated upstream and downstream by a rock separator wall (shown in photo below). The separator wall prevents flows from the multi-use path from entering the channel, creates ponding on the path and effectively cuts capacity of this culvert in half. In addition to increasing culvert capacity, removing the pedestrian separator wall and grading the inlet and outlet conditions for the creek and path would allow greater flows to pass through this culvert unencumbered. Pedestrian and creek separation and safety will be addressed during the design phase. It is anticipated that the multi-use path will carry some flow during smaller events such as a 2-year storm. The culvert in located on city right of way and there are no access issues. Culvert R3‐2: Underpass at US 36 Culvert R3-3: Steel Pipe Culverts at Saint Andrew Church Driveway Improvement Size Width (ft) Shape Length (ft) % of 100-year Storm Existing (2) 43” x 68” 12.5 Elliptical 40 0% Replace Driveway Bridge 40 Bridge 40 100% The driveway culverts at Saint Andrew Presbyterian Church are undersized and become completely blocked during flood events. During the September 2013 flood event, waters passed over the driveway, peeling away asphalt and blocking main access to the church from Baseline Road. Removing these culverts and replacing with a driveway bridge will alleviate the hydraulic limitation and allow larger storm event flow to pass more easily through this area. The culvert in located on private property and an easement agreement will be needed. Reach 3A: Channel Improvements Location Improvement Length (ft) % of 100-year Storm US 36 to CDOT Right of Way Increase channel capacity and re-grade multi-use path 142 100% CU Property Increase channel capacity in conjunction with CU Master Plan 2004 100% Church Property (upstream of driveway) Mowing, grading, edging with boulders and channel widening 56 100% Church Property (downstream of driveway) Mowing, grading, edging with boulders and channel widening 94 100% Culvert R3-3: Saint Andrew Church Driveway Attachment A: Bear Creek MItigation Plan
BEAR CANYON CREEK FLOOD MITIGATION PLAN 16 REACH 3B: BASELINE ROAD TO UPSTREAM OF FOOTHILLS PARKWAY Bear Canyon Creek crosses under Baseline Road and then through culverts at Gilpin Drive and Mohawk Drive. The drainageway then passes over Wellman Ditch, past Foothills Parkway and confluences with Boulder Creek near the intersection of Arapahoe Avenue and Foothills Parkway. Culvert R3-4: Concrete Underpass at Baseline Road Improvement Size Width (ft) Shape Length (ft) % of 100-year Storm Existing (2) 7’ x 12’ 25 Box 186 27% Replace (2) 7.5’ x 28’ 56 Box 186 100% Culvert R3‐4: Underpass at Baseline Road The underpass and culvert at Baseline Road are at an acute angle that can be uncomfortable for multi-use path users and do not pass 100-year storm flows. This culvert should have increased capacity and a wider angle in the path that can provide improved line of sight for users. The culvert in located on city right of way and there are no access issues. Culvert R3-5: Concrete Underpass at Gilpin Drive Improvement Size Width (ft) Shape Length (ft) % of 100-year Storm Existing 7’ x 20’ 20 Box 51 43% Replace (2) 8’ x 20’ 40 Box 51 100% The culvert at Gilpin Drive is a major pinch point for the entire Bear Canyon Creek drainageway. Increasing capacity at this location will allow for improvements upstream to take place without increasing damage downstream. Gilpin Drive is also a heavily used secondary access for High Peaks Elementary School and construction should occur during the summer months to prevent disruption of students’ school commute. Culvert R3-6: Concrete Underpass at Mohawk Drive Improvement Size Width (ft) Shape Length (ft) % of 100-year Storm Existing 7’ x 20’ 20 Box 72 41% No Improvements The underpass at Mohawk Drive has performed well in previous large-scale storm events such as September 2013. The Best Available Information model indicates that upstream improvements will not create additional risk at this location. No capacity increases are recommended for this culvert. Reach 3B: Channel Improvements & Stormdrain Reconfiguration Location Improvement Length (ft) % of 100-year Storm Near Gilpin Drive Channel grading and widening including multi-use path reconfiguration 613 100% Gilpin Drive Culvert Reconfigure stormdrain on upstream end in conjunction with box culvert replacement n/a 100% The channel at Gilpin Drive needs to be extensively graded and widened to accommodate the proposed Gilpin Drive underpass. In addition, there is a stormdrain outfall on the upstream headwall of the culvert. Should design and construction ensue, this stormdrain should be moved to the downstream end of the culvert and reconfigured to point more in parallel with the creek flows. The culvert in located on city owned property and there are no access issues. Attachment A: Bear Creek MItigation Plan
BEAR CANYON CREEK FLOOD MITIGATION PLAN 17 SECTION 5: PHASING & NEXT STEPS PROJECT PHASING The Gilpin Drive and Baseline Road box culverts are the key pinch points in the drainageway. Without upsizing these culverts, improvements upstream of Baseline Road will create negative impacts downstream of Gilpin Drive. Recommended phasing for improvements is described in the table at right. Generally, improvements go from downstream to upstream in accordance with engineering best practices. However, there are some recommended improvements that can be constructed out of sequence with no negative downstream impacts. These projects include; sediment removal at the Wildwood Culvert, removal of the Ithaca Drive steel culvert and sediment and debris removal throughout the drainageway. VEGETATION MANAGEMENT & MAINTENANCE PLAN Proper vegetation management in riparian, wetland, and stream areas can provide many benefits to ecosystems including wildlife habitat, bank stabilization, water filtration and can assist with preventing or reducing the impacts of flooding. Mitigation design needs to contain vegetation seeding and planting plans that are comprised of native plants that provide habitat for wildlife, debris transport, treatment and removal of non-native species and monitoring of vegetation following implementation to ensure condition is not compromised over time. The city is currently implementing new asset management software that will provide greater accuracy in determining maintenance needs and improved efficiency when scheduling for regular maintenance activities. FUTURE FUNDING The city’s flood management program is comprised of Boulder Creek and fourteen major drainageways, where over $160M of flood mitigation improvements have been identified city wide. Based on current funding levels, it is anticipated that it will require more than 80 years to complete these projects. In the Stormwater and Flood Management Utility, the majority of the project funding is prioritized by life safety (high hazard) and critical facility (vulnerable population) hazard mitigation issues but other factors apply, such as: Flood emergency response capability Property damage mitigation Collaboration with other Greenways Program Objectives Potential for operation and maintenance cost savings Accommodating new growth and development Opportunities to leverage outside funding The current six-year Capital Improvements Program (CIP) includes approximately $500,000 for improvements along Bear Canyon Creek. The city will seek all opportunities for collaborative funding efforts including; adjacent transportation projects, the University of Colorado or the Federal Emergency Management Agency (FEMA). Table 4: Recommended Improvements Phasing Plan Phase Location Recommendation Phase Cost 1 Gilpin Drive Increase channel capacity near Gilpin Drive $3,617,000 Gilpin Drive Increase culvert size to (2) 8ft x 20ft concrete boxes Baseline Road Increase culvert size to (2) 7.5ft x 28ft concrete box 2 Downstream of Church Increase channel capacity $601,000 Saint Andrew Church Replace culverts with 40ft driveway bridge Upstream of Church Increase channel capacity 3 University of Colorado Increase channel capacity in conjunction with CU Master Plan $1,584,000 4 US 36 to CDOT right of way Increase channel capacity and reconfigure multi-use path $980,600 US 36 Increase culvert size to (2) 8.5ft x 14ft concrete boxes and reconfigure pedestrian separator wall in underpass and grade multi-use path and channel downstream to improve the inlet and outlet condition 5 Broadway Sediment and debris removal from Broadway to Martin Drive $2,142,500 Broadway Modify inlet conditions to increase capacity Harvard Lane Increase culvert size to (2) 7.5ft x 10ft concrete boxes Stanford Avenue Increase channel capacity from Stanford Avenue to Harvard Lane 6 Table Mesa Drive Remove sediment in culverts at Ithaca Drive, Yale Road, Gillaspie Drive and Stanford Avenue including gravel bars and vegetation blocking inlet and outlet $1,554,000 Lehigh Street Increase culvert size to 7.5ft x 28ft concrete box none Wildwood Road Grade channel and widen floodplain from Wildwood Road to Ithaca Drive $514,000 Ithaca Drive Remove steel culvert and grade channel in conjunction with stormwater improvement project at Ithaca Drive none Wildwood Road Remove sediment in culvert, including gravel bars and vegetation blocking inlet and outlet n/a Martin Drive Continue good maintenance Moorhead Avenue Continue good maintenance Mohawk Drive Continue good maintenance TOTAL $11,000,000 Attachment A: Bear Creek MItigation Plan
BEAR CANYON CREEK FLOOD MITIGATION PLAN 18 MITIGATION PLANNING & CLIMATE CHANGE “The mean global surface temperature has risen by about 0.7- 1.5º F during the last century. This increased temperature contributes to rising sea levels, increased summer drought in some areas, more intense precipitation and weather events, habitat disruption that could lead to species extinction, and other possible serious effects. For Colorado, climate change will likely mean diminished snow pack, increased drought, more insect outbreaks in forests, an earlier and longer wildfire season, reduced habitat for native species, and less economic growth, according to studies on the impacts of climate change on the Rocky Mountain region.” -City of Boulder Climate Action Plan Traditional floodplain models utilize historic flood events for hydrologic input. Because of climate change, variations in temperature and precipitation are anticipated, although the impact of these changes on flooding and flood risk in the front range are unknown. Climate change and future flood risk should be taken into account during design of mitigation measures outlined in this document. Attachment A: Bear Creek MItigation Plan
BEAR CANYON CREEK FLOOD MITIGATION PLAN 19 SECTION 6: REFERENCES & ACKNOWLEDGEMENTS REFERENCES A September to Remember; Urban Drainage and Flood Control District, 2014. Boulder Valley Comprehensive Plan; 2010; https://www-static.bouldercolorado.gov/docs/boulder-valley-comprehensive-plan-2010-1-201410091122.pdf City of Boulder-Greenways Master Plan; 2010; https://www-static.bouldercolorado.gov/docs/2011-greenways-master-plan-update-1-201304221316.pdf Climate Action Plan; 2006; https://www-static.bouldercolorado.gov/docs/city-2006-climate-action-plan-1-201305081127.pdf Flood Hazard Area Delineation- Boulder and Adjacent County Drainageways; Greenhorne and O’Mara, 1987. Major Drainageway Planning Study - Boulder and Adjacent County Drainageways ‘Phase A’; Greenhorne and O’Mara, 1984. Major Drainageway Planning Study - Boulder and Adjacent County Drainageways ‘Phase B’; Greenhorne and O’Mara, 1987. Rainfall-Runoff Analysis for the September 2013 Flood in the City of Boulder, Colorado; Prepared by Wright Water Engineers for the City of Boulder and released in Sept. of 2014. Soil Survey of Boulder County Area, Colorado, United States Department of Agriculture Soil Conservation Service in cooperation with Colorado Agriculture Experiment Station, 1975 Summary Report of Private Property and Resident Flood Impact Survey and Analysis, September 2013 Flood Disaster prepared by the City of Boulder-Utilities Division; Dec. 3, 2014: https://www-static.bouldercolorado.gov/docs/summary-report-private-property-resident-september-2013-flood-impact-survey-analysis-1-201412031729.pdf ACKNOWLEDGEMENTS This report was completed with the support and input from various individuals at the City of Boulder, the UDFCD and Amec Foster Wheeler. The key participants in the development of this memorandum are shown in the following table: Project Team Affiliation Role Ward Bauscher City of Boulder Project Manager Annie Noble City of Boulder Flood and Greenways Engineering Coordinator Christin Shepherd City of Boulder Civil Engineer I Ryan Martin City of Boulder GIS Analyst Shea Thomas UDFCD Project Manager Joel McGuire Amec Foster Wheeler Senior Water Resource Engineer Jeff Brislawn Amec Foster Wheeler Lead Associate Melissa Greulich Amec Foster Wheeler Biologist and GIS Analyst Sara Johnson Amec Foster Wheeler Staff Engineer Attachment A: Bear Creek MItigation Plan
BEAR CANYON CREEK FLOOD MITIGATION PLAN APPENDIX A: BEAR CANYON CREEK WATERSHED INFORMATION Attachment A: Bear Creek MItigation Plan
LAND USE Upstream of the city limits, most of the land within the Bear Canyon Creek watershed is preserved as city Open Space. Within the city limits, the majority of the property is comprised of low density, residential zoning districts (RE, RL-1 and RL-2). Density intensifies at major intersections, such as Table Mesa and Broadway as well as Foothills Parkway and Baseline Road where property is zoned Mixed and High Residential (RM-1, RM-2, and RH-4) as well as commercial (BC-1 and BC-2). The land areas zoned Public (P) contain the National Institute of Standards and Technology (NIST), the University of Colorado, and Boulder Community Hospital. There is a small segment of Agricultural land (A) where Bear Canyon Creek converges with Boulder Creek. The southeast corner of Table Mesa Drive and Broadway is currently developed as commercial property only but is zoned as commercial property with a mixed use buffer. Should future development occur in this area, it would provide an opportunity to increase flow capacity in Bear Canyon Creek along Table Mesa Drive as well as the culvert below Broadway. The Bear Canyon Creek watershed is fully developed within city limits and future land use will be similar to existing conditions. Limited in-fill and development opportunities are available and areas within the floodplain are subject to city flood regulations which includes a ban on construction in the high hazard zone. Attachment A: Bear Creek MItigation Plan
SOILS According to the Soil Survey of Boulder County Area, Colorado (United States Department of Agriculture Soil Conservation Service in cooperation with Colorado Agriculture Experiment Station (1975)), the land within the Bear Canyon Creek watershed is comprised of the following soil classifications: Baller Stony Sandy Loam (BaF), Colluvial Land (Cu), Fern Cliff-Allens Park-Rock Outcrop Complex (FcF), Godvale Rock Outcrop Complex (Gfr), Juget-Rock outcrop complex (Jrf), McClave Clay Loam (Mm), Nederland Series (NdD), Niwot Series (Nh), Nunn Clay Loam (NuB), Rock Outcrop (Ro), Terrace Escarpments (Te), and Valmont Clay Loam (VaB). The upper portion of the watershed is predominantly Fern Cliff-Allens Park-Rock Outcrop Complex (FcF) and Juget-Rock outcrop complex (Jrf). These soils consist of stony sandy loam, gravely sandy loam and rock outcrops on mountain side slopes. The runoff potential is medium to rapid and the erosion potential is high. The central part of the watershed contains Rock Outcrop (Ro) and Godvale Rock Outcrop Complex (Gfr). Steep rock outcrops with exposed bedrock dominate. Pockets of gravely, loamy sand allow roots to penetrate to depths of 40 to 60 inches or more. These areas provide ideal habitat for wildlife. A band of Baller Stony Sandy Loam (BaF) exists along the city limits in the middle watershed. These soils are shallow and well drained with rapid permeability, high erosion hazard and rapid runoff potential Further down in the watershed, as Bear Canyon Creek enters the City of Boulder, Nederland Series (NdD) is the predominant soil type with pockets of Colluvial Land (Cu), McClave Clay Loam (Mm), and Terrace Escarpments (Te). The Nederland series (NdN) is made up of deep, well-drained soils that formed on old high terraces and alluvial fans. The soils developed on loamy alluvium that contains many cobblestones and other stones. These soils have moderate permeability and roots can penetrate to a depth of 60 inches or more. These areas have many stones and cobblestones on the surface. Runoff is slow to medium on this soil and the hazard is slight. Cu soils vary widely in depth, texture, color, and stoniness due to the runoff from adjacent slopes that these lands receive. Most areas of Colluvial land have stones and cobbles on the surface. The erosion hazard associated with Cu soils is high. McClave Clay Loam soils are made up of deep, somewhat poorly drained soils with moderate permeability. Runoff is slow and erosion hazard is slight. Te soils have many cobbles and stones on the surface. Runoff is rapid and the erosion hazard is high. Nunn Series (NuB, NuC, and NuD) soils are located at the confluence with Boulder Creek. The Nunn series is made up of deep, well drained soils that have slow and moderately slow permeability. Roots can penetrate to a depth of 60 inches or more. Runoff ranges from medium to rapid on these soils and the erosion hazard is moderate to high. Bear Canyon Creek Watershed Attachment A: Bear Creek MItigation Plan
NOTABLE LANDMARKS & HISTORY Notable Landmarks within the watershed include the Frederick W. Kohler Homestead, the William Martin Farmhouse, Green Mountain Cemetery, the NIST Facility, Martin Acres Neighborhood, Boulder Fire Station #3, the NCAR Building, the George Reynolds Branch Library, and Fairview High School. FREDERICK W. KOHLER HOMESTEAD Built in 1862, Frederick W. Kohler and family homestead was an 800-acre farm along Baseline Road in Boulder. Kohler became a large stockholder in the Boulder National Bank and served two terms as Boulder County Commissioner. Kohler Reservoir was named after him and was originally used as a watering hole for his cattle. WILLIAM MARTIN FARMHOUSE Built in 1875, William Martin built a farmhouse on an old campsite used in the 1860’s by prospectors on their way to the mines. GREEN MOUNTAIN CEMETERY In 1904, the first burial at Green Mountain Cemetery took place. Graves from Columbia Cemetery, which was seen as a less desirable place for burial, were exhumed and brought to the new cemetery. POST WWII DEVELOPMENT From the 1950’s-1960’s, South Boulder saw the addition of 2,500 residential houses immediately following the end of World War II. NATIONAL INSTITUTE OF STANDARDS &TECHNOLOGY FACILITY In 1954, President Eisenhower dedicated the National Institute of Standards and Technology (NIST) facility. Attachment A: Bear Creek MItigation Plan
MARTIN ACRES NEIGHBORHOOD In 1955, George and Everett Williams developed the Martin Acres neighborhood, named after William Martin, who used to operate a ranch in the area. BOULDER FIRE STATION #3 In 1964, architects Thomas Nixon and Lincoln Jones designed Boulder Fire Station #3 in the Usonian style. NCAR BUILDING In 1966, Walter Orr Roberts worked with I.M. Pei to design the NCAR building. A ballot measure was passed to allow its construction on Table Mesa. GEORGE REYNOLDS BRANCH LIBRARY In 1969, the George Reynolds Branch Library, named after the CU literature professor, is the city’s first branch library. FAIRVIEW HIGH SCHOOL In 1971, modernist architect Hobart Wagener designed Fairview High School, Boulder’s second high school. Attachment A: Bear Creek MItigation Plan
BEAR CANYON CREEK FLOOD MITIGATION PLAN APPENDIX B: WETLAND EVALUATIONS Attachment A: Bear Creek MItigation Plan
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BEAR CANYON CREEK FLOOD MITIGATION PLAN APPENDIX C: RELEVANT PLANNING DOCUMENT EXCERPTS Attachment A: Bear Creek MItigation Plan
BOULDER VALLEY COMPREHENSIVE PLAN The following applicable policies are included in the BVCP: 3.19 Preservation of Floodplains Undeveloped floodplains will be preserved or restored where possible through public land acquisition of high hazard properties, private land dedication and multiple program coordination. Comprehensive planning and management of floodplain lands will promote the preservation of natural and beneficial functions of floodplains whenever possible. 3.20 Flood Management The city and county will protect the public and property from the impacts of flooding in a timely and cost‐effective manner while balancing community interests with public safety needs. The city and county will manage the potential for floods by implementing the following guiding principles: a) Preserve floodplains b) Be prepared for floods c) Help people protect themselves from flood hazards d) Prevent unwise uses and adverse impacts in the floodplain e) Seek to accommodate floods, not control them. The city seeks to manage flood recovery by protecting critical facilities in the 500‐year floodplain and implementing multi hazard mitigation and flood response and recovery plans. 3.21 Non‐Structural Approach The city and county will seek to preserve the natural and beneficial functions of floodplains by emphasizing and balancing the use of non‐structural measures with structural mitigation. Where drainageway improvements are proposed, a non‐structural approach should be applied wherever possible to preserve the natural values of local waterways while balancing private property interests and associated cost to the city. 3.22 Protection of High Hazard Areas The city will prevent redevelopment of significantly flood‐damaged properties in high hazard areas. The city will prepare a plan for property acquisition and other forms of mitigation for flood‐damaged and undeveloped land in high hazard flood areas. Undeveloped high hazard flood areas will be retained in their natural state whenever possible. Compatible uses of riparian corridors, such as natural ecosystems, wildlife habitat and wetlands will be encouraged wherever appropriate. Trails or other open recreational facilities may be feasible in certain areas. 3.23 Larger Flooding Events The city recognizes that floods larger than the 100‐year event will occur resulting in greater risks and flood damage that will affect even improvements constructed with standard flood protection measures. The city will seek to better understand the impact of larger flood events and consider necessary floodplain management strategies including the protection of critical facilities COMPREHENSIVE FLOOD AND STORMWATER UTILITY MASTER PLAN The CFS contains the following guiding principles for flood management: 1. Preserve Floodplains (Preservation); 2. Be Prepared for Floods (Preparedness); 3. Help People Protect Themselves from Flood Hazards (Education); 4. Prevent Adverse Impacts and Unwise Uses in the Floodplain (Regulation); 5. Seek to Accommodate Floods, Not Control Them (Mitigation). More detail about each of these guiding principles can be found in Chapter 3 of the CFS. The fifth principal, as listed above, is directly related to mitigation and, in the CFS, more completely states: Seek to accommodate floods, not control them through planned and monitored system maintenance, nonstructural flood proofing, opening non‐containment corridors, overbank land shaping to train flood waters, and limited structural measures at constrained locations. Possible tools for implementation include: o Update mitigation master plans to emphasize nonstructural measures. o Re‐evaluate mitigation priorities to eliminate bottlenecks, acquire land to avoid channel improvements, provide non‐structural overbank grading, target limited flood protection improvements for high hazards, and research alternative mitigation approaches. o Assess any need for structural improvements with evaluation of multiple alternatives. o Focus on mitigating high hazard locations citywide and give priority to areas of the greatest risk. URBAN DRAINAGE AND FLOOD CONTROL DISTRICT (UDFCD) DRAINAGE CRITERIA MANUAL The UDFCD Drainage Criteria Manual contains the following basic policies: The major drainageway system shall be capable of conveying water without flooding buildings and shall remain relatively stable during a 100‐year flood. Public safety is fundamental to the major drainageway system. Public acceptance of the major drainageway system depends on a multitude of factors such as public perception of flood protection, channel aesthetics, right‐of‐way, open space preservation, and channel maintenance. Identify areas with potential for recreational use. Consider environmental impacts and benefits and examine the advantages and disadvantages. Open channels are more desirable than underground conduits in urban areas because they are closer in character to natural drainageways and offer multiple use benefits. Consider two‐stage channels. In some cases, it may be desirable to balance the 100‐year flow between a formal channel and the adjacent floodplain. GREENWAYS MASTER PLAN The Greenways Program in the City of Boulder was an outgrowth of the Boulder Creek Corridor Project. It was created on the basis of recognition that stream corridors are a vital link in the larger environmental system and Attachment A: Bear Creek MItigation Plan
that each stream is a natural and cultural resource. The purpose of the Greenways Program is to extend the stewardship of the City of Boulder to the important riparian areas along the tributaries of Boulder Creek. The objects of the Greenways Program include: Protect and restore riparian, floodplain and wetland habitat; Enhance water quality; Mitigate storm drainage and floods; Provide alternative modes of transportation routes or trails for pedestrians and bicyclists; Provide recreation opportunities; Protect cultural resources. Objectives and goals core to the Greenways Master Plan and related to the vegetation management portion of the project include: • Protect and enhance areas with high habitat value • Restore habitat for native species • Protect areas for species of concern • Protect and restore high quality wetlands • Maintain and enhance stream channel stability • Preserve and enhance stream corridor water quality function Attachment A: Bear Creek MItigation Plan
BEAR CANYON CREEK FLOOD MITIGATION PLAN APPENDIX D: ENVIRONMENTAL REPORT & HABITAT ASSESSMENT Attachment A: Bear Creek MItigation Plan
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x 5HVWRUHKLVWRULFDOVWUHDPPHDQGHULQJx 5HJUDGHVORSHVWRDOORZYHJHWDWLRQWRWUDQVLWLRQIURPULSDULDQWRXSODQGKDELWDWx 5HFRQQHFWWKHIORRGSODLQZKHUHWKHFKDQQHOLVLQFLVHGDQGFRQVWUDLQHGE\GHYHORSPHQWRQERWKVLGHV%DQNHURVLRQLQFLVHGFKDQQHOVDQGVHGLPHQWDWLRQRIWKHFUHHNZHUHQRWHGDWPDQ\RIWKHSORWV'DWDIRUPVLQ$SSHQGL[%SURYLGHPRUHLQIRUPDWLRQDERXWHDFKSORWORFDWLRQDQGVSHFLILFLVVXHVVHHQDQGSKRWRVRIK\GURORJLFIHDWXUHVFDQEHIRXQGLQ$SSHQGL[& +$%,7$748$/,7<,QIRUPDWLRQUHJDUGLQJKDELWDWTXDOLW\DQGYHJHWDWLRQKHDOWKZHUHDOVRGRFXPHQWHGEXWQRWLQDVPXFKGHWDLO$VXPPDU\RIJHQHUDOILQGLQJVLQFOXGH x 9HJHWDWLRQVWUDWDZHUHZHOOUHSUHVHQWHGWKURXJKRXWWKH5HDFKHV5HDFKKDGPXFKGHQVHUYHJHWDWLRQDQGGLYHUVLW\WKDQ5HDFK5HDFKDOVRJHQHUDOO\KDGPRUHQRQQDWLYHVSHFLHVSUHVHQWx 1DWLYHSODQWKDELWDWFRXOGEHHQKDQFHGZLWKUHVWRUDWLRQEXWFXUUHQWO\LVODFNLQJEHFDXVHRIWKHGHQVLW\RIDQGFRPSHWLWLRQIURPQRQQDWLYHVSHFLHVx %LUGKDELWDWLVSUHVHQWDORQJWKHHQWLUHFUHHNDQGVHYHUDOVSHFLHVZHUHVHHQDQGKHDUGGXULQJWKHVXUYH\5HDFKKDVOHVVGLYHUVLW\DQGPRUHGLVWXUEDQFHIURPPRZLQJRIQHDUE\XSODQGJUDVVODQGVZKLFKLVOLNHO\WRGLVUXSWQHVWLQJLQWKHDUHD5HDFKDQGDUHYHU\QDUURZDQGVSHFLHVWKDWUHTXLUHODUJHVZDWKVRIFRQWLJXRXVKDELWDWZLOOQRWXVHWKHVHDUHDV$PHF)RVWHU:KHHOHU3URMHFW1R x $TXDWLFKDELWDWTXDOLW\ZDVYDULDEOHWKURXJKRXW5HDFKDQG3RVLWLYHKDELWDWTXDOLW\FKDUDFWHULVWLFVGRFXPHQWHGZHUHWKHSUHVHQFHRIFRYHUIURPIDOOHQORJVDQGRYHUKDQJLQJYHJHWDWLRQULIIOHVIURPURFNVLQVWUHDPDQGFUHHNPHDQGHULQJ+RZHYHUVRPHDUHDVFRPSOHWHO\ODFNHGWKHVHSRVLWLYHFKDUDFWHULVWLFV$GGLWLRQDOO\VRPHRIWKHVHFKDUDFWHULVWLFVVXFKDVWKHSUHVHQFHRIYHJHWDWLYHDQGIDOOHQORJFRYHUFRPSURPLVHWKHIORZRIWKHVWUHDP$EDODQFHEHWZHHQDTXDWLFKDELWDWDYDLODELOLW\DQGKHDOWK\VWUHDPJHRPRUSKRORJ\PXVWEHPHWxPreble’s meadow jumping mouse habitat potentially occurs at some of the plot locations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x 3URWHFWDQGHQKDQFHDUHDVZLWKKLJKKDELWDWYDOXHAttachment A: Bear Creek MItigation Plan
$PHF)RVWHU:KHHOHU3URMHFW1R x 5HVWRUHKDELWDWIRUQDWLYHVSHFLHVx 3URWHFWDUHDVIRUVSHFLHVRIFRQFHUQx 0DLQWDLQDQGHQKDQFHVWUHDPFKDQQHOVWDELOLW\x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ttachment A: Bear Creek MItigation Plan
BEAR CANYON CREEK FLOOD MITIGATION PLAN APPENDIX E: CULVERT BLOCKAGES Attachment A: Bear Creek MItigation Plan
The table below lists the culvert blockages used in the 1987 FHAD and the culvert blockages used in the Best Available Information model. Existing Conditions Culvert Blockages Culvert ID Location FHAD Blockage Existing Condition Blockage R1-1 Wildwood Road 40% 55% R1-2 Ithaca Drive 100% 100% None Pedestrian Bridge upstream of Lehigh Street 30% 0% R2-1 Lehigh Street 75% 75% R2-2 Ithaca Drive 50% 50% R2-3 Yale Road 50% 50% R2-4 Gillaspie Drive 50% 50% None Pedestrian Bridge at Stanford Avenue 0% 0% R2-5 Stanford Avenue 50% 50% R2-6 Harvard Lane 0% 60% R2-7 Broadway Street 75% 30% None Pedestrian Bridge at Dartmouth Avenue 75% 0% R2-8 Martin Drive 50% 50% R3-1 Moorhead Avenue 20% 20% R3-2 US 36 0% 65% None Pedestrian Bridge downstream of US 36 0% 0% None University of Colorado ‐ 100% R3-3 Saint Andrew Church 30% 75% R3-4 Baseline Road 50% 50% R3-5 Gilpin Drive 10% 15% R3-6 Mohawk Drive 0% 15% Attachment A: Bear Creek MItigation Plan
BEAR CANYON CREEK FLOOD MITIGATION PLAN APPENDIX F: ALTERNATIVE ANALYSIS DATA Attachment A: Bear Creek MItigation Plan
FloodMitigationMasterPlanBearCanyonCreekMitigationAlternativeInventoryReachLocationCodeMitigationTypeCountCodeEffort CountUpdated: jsmv2.21A CityLimitstoBearCanyonPark CR CrossingImprovement 24MAMaintenance71B BearCanyonParktoLehigh EC ErosionControl/ChannelStabilization 16CMCapitalMaintenance262A LehightoBroadway DM DebrisManagementArea 4CICapitalImprovement162B BroadwaytoMoorheadFC FloodplainConnection/StorageArea 5NINoImprovement113AMoorheadtoBaselineSC SpillControl63BBaselinetoMohawkRM RiparianManagement5RecordCount: 59123456 78 9101112131415 16 171819202122 23 24 252627Id SiteMitCodeReach No.ConͲceptualEffortCode MitigationTypeLocationUSRiverStationDSRiverStation Midpoint ExistingConditionsDescription100ͲYearDischarge(cfs)FHADBlockageReportedFHADCulvert/BridgeFlow(cfs)TheoreticalCapacity(noblockage)(cfs)Theoretical%of100ͲYrCapacity15%(City)Capacity(cfs)City%of100ͲYrCapacityExistingConditionsBlockageExistingConditionsCapacity(cfs)Existing%of100ͲYrCapacityMinimumBlockage(GoodMaintenance)MaintͲenanceCapacity(cfs)MaintͲenance%of100ͲYrCapacity 100ͲYrMitigationConceptLevelofEffort4CRͲR1Ͳ1.2CR1 1.2MACrossingWildwoodRoadCulvert204+61 203+61 204+11Debrisblockage 1063 40% 1600 2002 188% 55% 792 74% 40% 1098 103%Removevegetation,gravelbars Maintenance10CRͲR1Ͳ2.1CR 1 2.1CMCrossingBoilerCulvertatIthacaDrive(W)188+16 188+00 188+081cellculvert:5' 1063 100%Ͳ Ͳ Ͳ Ͳ100% 1063 100% 100%Ͳ ͲRemoveculvertCapitalMaintenance11CRͲR1Ͳ3.1CR 1 3.1NICrossingPedestrianBridgeUSofLehigh186+31 186+01 186+1650'WBridge,NoPiers 1063 30%Ͳ Ͳ Ͳ Ͳ0% 1193 112% 0% 1193 112%NoImprovementNoImprovement13CRͲR2Ͳ1.1CR 2 1.1CICrossingLehighStreetCulvert177+39 173+57 175+482cellculvert:4'R×8'S1600 75% 35262339% 520 32% 75% 138 9% 30% 420 26%IncreaseCapacityCapitalImprovement17CRͲR2Ͳ2.1CR 2 2.1NICrossingIthacaDrive(E)Culvert167+65 166+51 167+082cellculvert:4'R×8'S1600 50% 42764740% 581 36% 50% 322 20% 20% 542 34%NoImprovementNoImprovement21CRͲR2Ͳ3.1CR 2 3.1NICrossingYaleRoadCulvert160+82 159+62 160+222cellculvert:4'R×8'S1655 50% 41568141% 566 34% 50% 313 19% 20% 528 32%NoImprovementNoImprovement23CRͲR2Ͳ4.1CR 2 4.1NICrossingGillaspieDriveCulvert154+59 153+39 153+992cellculvert:4'R×8'S1745 50% 40145226% 450 26% 50% 241 14% 20% 418 24%NoImprovementNoImprovement25CRͲR2Ͳ5.1CR 2 5.1NICrossingStanfordAvenuePedestrianBridge148+64 148+46 148+5540'WBridge,NoPiers 1835 0%Ͳ Ͳ Ͳ Ͳ0%Ͳ Ͳ0%Ͳ ͲNoImprovementNoImprovement27CRͲR2Ͳ6.1CR 2 6.1CICrossingStanfordAvenueCulvert147+43 146+23 146+832cellculvert:4'R×8'S1835 50% 37854129% 435 24% 50% 219 12% 20% 402 22%IncreaseCapacityCapitalImprovement28CRͲR2Ͳ7.1CR 2 7.1CICrossingHarvardLaneCulvert142+97 140+65 141+812cellculvert:4.5'R×8'S1930 0% 25866935% 550 28% 60% 297 15% 20% 512 27%IncreaseCapacityCapitalImprovement31CRͲR2Ͳ8.1CR 2 8.1CICrossingBroadwayStreetCulvert139+32 137+66 138+49Singlecellculvert:7.5'R×23'S1930 75% 1930176291% 1429 74% 30% 1119 58% 20% 1324 69%IncreaseCapacityCapitalImprovement41CRͲR2Ͳ10.1CR 2 10.1CICrossingDartmouthPedestrianBridge128+88 128+78 128+83Singlecellculvert:7.5'R×23'S2100 75% NA142968% 1119 53% 0%Ͳ Ͳ20%Ͳ ͲIncreaseCapacityCapitalImprovement32CRͲR2Ͳ9.1CR 2 9.1NICrossingMartinDriveCulvert117+10 116+48 116+79LeftCulvert:7.5'R×24'SRightCulvert:6.5'R×7.5'S2210 50% 1398 1652 75% 1346 61% 50% 679 31% 20% 1243 56%NoImprovementNoImprovement33CRͲR3Ͳ1.1CR 3 1.1NICrossing MooreheadAvenueCulvert109+21 108+01 108+61Singlecellculvert:7.5'R×24'S2210 20% 2210150068% 1350 61% 20% 1350 61% 20% 1350 61%NoImprovementNoImprovement36CRͲR3Ͳ2.1CR 3 2.1CICrossingUSͲ36Culvert106+36 104+12 105+242cellculvert:7'R×14'S2925 0% 2925221476% 1817 62% 65% 651 22% 50% 975 33%IncreaseCapacityCapitalImprovement39CRͲR3Ͳ3.1CR 3 3.1NICrossingBikeBridgeDSofUSͲ36103+28 104+12 103+7040'WBridge,NoPiers 2925 0%Ͳ Ͳ Ͳ Ͳ0% 583 20% 0%Ͳ ͲNoImprovementNoImprovement42CRͲR3Ͳ4.1CR 3 4.1CICrossingCUCampus90+45 90+55 90+502cellculvert:18"Dia 2925Ͳ Ͳ Ͳ Ͳ Ͳ100% 0Ͳ100%Ͳ ͲReplaceexistinglowflowcrossingCapitalImprovement44CRͲR3Ͳ5.1CR 3 5.1CICrossingChurchDrivewayCulvert84+46 83+66 84+062ellipticalcellculvert:68"R×43"S 2925 30% 126743%Ͳ75% 10 0% 50% 35 1%InstallbridgeCapitalImprovement45CRͲR3Ͳ6.1CR 3 6.1CICrossingBaselineRoadCulvert80+98 79+22 80+102cellculvert:7'R×12'S2925 50% 716177461% 1451 50% 50% 798 27% 20% 1387 47%IncreaseCapacityCapitalImprovement46CRͲR3Ͳ7.1CR 3 7.1CICrossingGilpinDriveCulvert74+81 74+58 74+70Singlecellculvert:7'R×20'S3065 10% 1407156451% 1307 43% 15% 1307 43% 15% 1307 43%IncreaseCapacityCapitalImprovement47CRͲR3Ͳ8.1CR 3 8.1NICrossingMohawkDriveCulvert54+70 53+26 53+98Singlecellculvert:7.5'R×20'S3065 0% 3065151349% 1243 41% 15% 1243 41% 15% 1243 41%NoImprovementNoImprovementColExplanation:131987FHADdischargedata141987FHADreportedstructureblockage151987FHADreportedstructurecapacity16Theoreticalcapacity(noblockage)ascalculatedbasedonfieldmeasurements(HYͲ8v7.40)17Col16/Col13(%)18CapacitybasedonCityrequirementtoassume15%blockage20Blockagebasedonfieldobservations(see"BlockageMemo",2/2/16)21Capacityasdeterminedwithexistingconditionsblockage(HYͲ8v7.40)22Col21/Col13(%)23Blockagebasedon"GoodMaintenance";riparianmanagement,routinedebriscontrol,regularstructureinspection/maintenance24Capacityasdeterminedwithgoodmaintenanceblockage(HYͲ8v7.40)25Col24/Col13(%)26100ͲYrMitigationconcept27Levelofeffort(Maintenance,CapitolMaintenance,CapitalImprovementorNoImprovement)3/30/16ReachIndex MitigationTypeIndex ConceptualLevelofEffortIndexAttachment A: Bear Creek MItigation Plan
Bear Canyon CreekSkunk CreekAnderson Ditch ExtensionAndersonDitchWellmanDitchBr oadw
a
y US Hwy 36Moorhead AvBaseline Rd30th St28th StGillaspie
Dr
Foothills
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Lehigh St27th WyTable Mesa DrBroad
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MaintenanceFLO-2D Model Flood DepthsLegendCreekDitchCity Limits±01,000500FeetFlood Depths0.010 - 0.5000.501 - 1.5001.501 - 3.5003.501 - 6.5006.501 - 11.000Bear Canyon CreekSkunk CreekAnderson Ditch ExtensionAndersonDitchWellmanDitchBroad
w
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y US Hwy 36Moorhead AvBaseline Rd30th St28th StGillaspie DrFoothills Py
Lehigh St27th WyTable Mesa DrBroadway
Capital ImprovementsFLO-2D Model Flood DepthsLegendCreekDitchCity Limits±01,000500FeetFlood Depths0.010 - 0.5000.501 - 1.5001.501 - 3.5003.501 - 6.5006.501 - 11.000Attachment A: Bear Creek MItigation Plan
BEAR CANYON CREEK FLOOD MITIGATION PLAN APPENDIX G: RECOMMENDED IMPROVEMENT MAPS Attachment A: Bear Creek MItigation Plan
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Exst : 7.5 x 24 box and 6.5 x 7.5 boxRec : MaintenanceExst : Pedestrian BridgeRec: No ChangeExst : 7.5 x 23 boxRec : Reconfigure InletExst : (2) 4.5 x 8 boxRec : (2) 7.5 x 10 boxExst : Pedestrian BridgeRec : No Change
Exst : (2) 4 x 8 boxRec : 7.5 x 28 box
Exst : Pedestrian BridgeRec : No Change
Exst : 5ft Diameter Steel Pipe Rec : Remove
Exst : (2) 7 x 12 boxRec : MaintenanceBear Canyon Creek Exst : (2) 4 x 8 boxRec : Maintenance
Exst : (2) 4 x 8 boxRec : Maintenance
Gillaspie DrIthaca DrLehigh StBroadway
Darley Av
Dartmouth AvVassar Dr
Yale RdEmerson AvKohler DrStanford Av
Judson DrMartin DrDover Dr
Hartford DrS 38th StTa
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Heidelberg Dr
Iliff St Berea DrS 35th StEdinboro DrBe
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Endicott Dr
Juilliard StS 33rd StKenwood Dr S 32nd StS 39th StWildwood RdS 31st StFindlay WyS 34th StStephens Rd
Curie Cr
Kendall DrFairfield DrNorton StS 36th StAlbi
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yClaremont DrArmer Av
Britting Av
Everett Dr Carlock DrGeorgetown RdGoddard PlHi
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Hillsdale WyMiam
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r Drake StLoyola CtOverlook DrKenyon Cr
Howard Pl Dennison LnChase Ct
Yale CrFurman WyLan
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Broadw
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Hartford Dr
Table Mesa Dr
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Legend
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Ditch
City Limits
Channel Maintenance
Culvert Analyzed
Increase Channel Capacity
§Reconfigure Stormwater
0 500 1,000250 Feet
Bear Canyon Creek Mitigation PlanRecommended ImprovementsMap 1 of 2
Culvert Size in FeetHeight x Width
Attachment A: Bear Creek MItigation Plan
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Exst : 7 x 20 boxRec : (2) 8 x 20 box
Exst : (2) 7 x 12 boxRec : (2) 7.5 x 28 box
Exst : (2) 4 x 6 ellipticalRec : 40ft Driveway Bridge
Exst : Pedestrian BridgeRec : Replace in conjunctionwith CU Master Plan
Exst : (2) 7 x 14 boxRec : (2) 8.5 x 14 box and Remove Pedestrian Separator Wall
Exst : 7.5 x 24 boxRec : Maintenance
Exst : 7.5 x 24 box and 6.5 x 7.5 boxRec : Maintenance Bear Canyon CreekSkunk CreekExst : 7.5 x 20 boxRec : MaintenanceWellman Ditch(limits of study area)30th StUS
H
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Baseline Rd
E Aurora Av
Colorado Av
Moo
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v35th StMar
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r36th St37th St34th StInca PyAsh Av Hopi PlFox DrS 35th St31st StMohawk DrLipan WyApa
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dErie Dr38th St33rd StCh
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p
p
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Madison Av
39th St32nd StGilpin DrFoothills PyKiowa PlEvans DrS 31st St29th StS 32nd StDiscovery DrE Euclid Av
Eut
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S 33rd StInca PkHarrison AvS 38th StCa
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S 34th StBixby Av
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S 36th StKent StQuinn StO
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rPitkin DrSioux Dr
Denton Av
Morgan DrE College AvShadow Creek Dr
Fuller CtPennsylvania AvAdams Cr Innovation DrChase CtDavidson PlTalbot DrThomas DrFox Ct
Canyon Creek Rd
Apache C
tHolly PlDallas Pl
30th St38th StM
o
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a
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k
D
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31st St38th StFoothills Py
Inca PyDiscovery Dr
³
Legend
Creek
Ditch
City Limits
Channel Maintenance
Culvert Analyzed
Increase Channel Capacity
§Reconfigure Stormwater
0 500 1,000250 Feet
Bear Canyon Creek Mitigation PlanRecommended ImprovementsMap 2 of 2
Culvert Size in FeetHeight x Width
Attachment A: Bear Creek MItigation Plan
BEAR CANYON CREEK FLOOD MITIGATION PLAN APPENDIX H: BENEFIT COST ANALYSIS Attachment A: Bear Creek MItigation Plan
Flood Mitigation Master Plan Bear Canyon CreekPhase 2: Existing Conditions 50, 100 & 500 year Flood Loss EstimationRun Date: 8/24/2016Return PeriodWet Centroid CountDamaged Building CountBuilding DamageContents DamageTotal DamagesDisplacement Days 1 Total500-year Flood1223 50,364$ 9,413$ 59,777$ 0 Days100-Year Flood632 6,110$ 2,268$ 8,378$ 0 Days50-Year Flood412 6,110$ 2,268$ 8,378$ 0 DaysTotal2267 62,584$ 13,949$ 76,533$ 0 Days 2A Total500-year Flood6520 326,597$ 151,390$ 477,988$ 0 Days100-Year Flood3611 36,085$ 14,643$ 50,728$ 0 Days50-Year Flood175 14,672$ 3,580$ 18,253$ 0 DaysTotal11836 377,354$ 169,614$ 546,968$ 0 Days 2B Total500-year Flood414206 1,524,530$ 547,750$ 2,072,280$ 0 Days100-Year Flood282151 790,314$ 307,864$ 1,098,178$ 0 Days50-Year Flood224121 627,895$ 248,536$ 876,432$ 0 DaysTotal920478 2,942,739$ 1,104,151$ 4,046,890$ 0 Days3A Total500-year Flood3313 341,716$ 165,057$ 506,773$ 0 Days100-Year Flood2512 296,538$ 154,222$ 450,759$ 0 Days50-Year Flood2111 272,208$ 144,966$ 417,174$ 0 DaysTotal7936 910,462$ 464,245$ 1,374,707$ 0 Days 3B Total500-year Flood9022 243,404$ 76,347$ 319,751$ 315 Days100-Year Flood7118 206,372$ 65,937$ 272,308$ 225 Days50-Year Flood6817 180,633$ 58,322$ 238,956$ 225 DaysTotal22957 630,409$ 200,606$ 831,015$ 765 DaysGrand Total500-year Flood724264 2,486,611$ 949,958$ 3,436,569$ 315 Days100-Year Flood477194 1,335,418$ 544,934$ 1,880,352$ 225 Days50-Year Flood371156 1,101,519$ 457,673$ 1,559,192$ 225 DaysGrand Total1572614 4,923,548$ 1,952,565$ 6,876,112$ 765 DaysTotal Damages for Study Area by Return PeriodReach 1; US Study Limit to LehighReach 2A; Lehigh to BroadwayReach 2B; Broadway to MoorheadReach 3A; Moorhead to BaselineReach 3B; Baseline to Foothills PkwyFlood Mitigation Master Plan Bear Canyon CreekPhase 2: Recommended 50, 100 & 500 year Flood Loss EstimationRun Date: 8/24/2016Return PeriodWet Centroid CountDamaged Building CountBuilding DamageContents DamageTotal DamagesDisplacement Days 1 Total500-year Flood1213 50,364$ 9,413$ 59,777$ 0 Days100-Year Flood11 1,385$ -$ 1,385$ 0 Days50-Year Flood11 1,385$ -$ 1,385$ 0 DaysTotal1235 53,134$ 9,413$ 62,547$ 0 Days 2A Total500-year Flood5717 268,842$ 131,993$ 400,835$ 0 Days100-Year Flood2310 30,767$ 12,091$ 42,858$ 0 Days50-Year Flood124 13,088$ 3,580$ 16,668$ 0 DaysTotal9231 312,698$ 147,664$ 460,362$ 0 Days 2B Total500-year Flood382202 1,467,246$ 529,354$ 1,996,600$ 0 Days100-Year Flood245139 738,842$ 286,086$ 1,024,929$ 0 Days50-Year Flood175108 575,660$ 225,423$ 801,084$ 0 DaysTotal802449 2,781,749$ 1,040,863$ 3,822,612$ 0 Days3A Total500-year Flood284 100,891$ 84,858$ 185,750$ 0 Days100-Year Flood100-$ -$ -$ 0 Days50-Year Flood90-$ -$ -$ 0 DaysTotal474 100,891$ 84,858$ 185,750$ 0 Days 3B Total500-year Flood4411 182,101$ 52,314$ 234,415$ 315 Days100-Year Flood94 131,464$ 35,373$ 166,838$ 225 Days50-Year Flood54 109,773$ 29,702$ 139,475$ 225 DaysTotal5819 423,339$ 117,389$ 540,728$ 765 DaysGrand Total500-year Flood632237 2,069,445$ 807,932$ 2,877,377$ 315 Days100-Year Flood288154 902,459$ 333,550$ 1,236,009$ 225 Days50-Year Flood202117 699,906$ 258,706$ 958,612$ 225 DaysGrand Total1122508 3,671,810$ 1,400,188$ 5,071,998$ 765 DaysTotal Damages for Study Area by Return PeriodReach 1; US Study Limit to LehighReach 2A; Lehigh to BroadwayReach 2B; Broadway to MoorheadReach 3A; Moorhead to BaselineReach 3B; Baseline to Foothills PkwyAttachment A: Bear Creek MItigation Plan
BearCanyonCreekFloodMitigationMasterPlanPreliminaryCostEstimateSiteCode:UDFCDCostingTab:ModelUSStation:ModelDSStation:ModelLength:Span: 0Removeexisting5ͲftCMPRise: 0ExistingStructureLength: 16 LFNumberofBarrels: 0ExistingTotalStructureWidth: 5 ftLength: 0 LF/BarrelExistingStructureHeight: 5 ftWingwalls? NoExistingStructureVolume: 400ft3ProposedStructureVolume: 0ft3ProposedVolumeRemoval=ProposedExcavationProposedExcavation: 15 CYProposedStructureRemoval: 16 LF/BarrelCapitalImprovementSubtotal:11,380.00$CostFrequency(LS)(peryear)Dewatering: LS$5,000.00Culvert:LF$1.00 $0.00Mobilization: 5%$569.00Inlet:EA$52.00 $0.00TrafficControl: LS$2,500.00Channel:150 LF$2.00 $100.00UtilityCoordination: LS$10,000.00Mowing:ACRES $52.00 $0.00ErosionControl: 5%$569.00Trails:LF$5.00 $0.00AdditionalCostsSubtotal:$18,638.00MaintenanceCostsSubtotal:$100.00Engineering: 15%$4,503.00Legal/Administrative: 5%$1,501.00ConstructionMgmt: 10%$3,002.00Contingency: 25%$7,505.00OtherCostsSubtotal: $16,511.00TotalCapitalImprovementCost:46,529$TotalOperationandMaintenanceCostsOver50Years:2,148$TheexistingculvertatIthacaDriveisproposedtoberemovedbutnotreplaced.Thecostingconsiders2channelimprovementsaftertheculvertremoval:1.75LFof24"boulderedging2.Groutedboulderdropstructure(14squareyardsof18"boulders)CapitalImprovementCostSummaryCRͲR1Ͳ2.1BoilerCulvertatIthacaDriveGeneralInformationBoilerCulvertatIthacaDriveCRͲR1Ͳ2.1R1ͲReach2.1188161880016ProposedCrossingModificationProposedCBCDesignProposedCulvertRemovalandExcavationAdditionalCapitalImprovementCostsMaintenanceCosts%ofSubtotalQuantity Units UnitCost CostBearCanyonCreekFloodMitigationMasterPlanPreliminaryCostEstimateSiteCode:UDFCDCostingTab:ModelUSStation:ModelDSStation:ModelLength:Mowing: 1493 LFChannelModificationReach: 760 LF10ͲftͲWideTrail/Path: 0 LF10ͲftͲWideSidewalk: 0 LFBridges: 0Culverts: 50 LFExcavation(CY)ECͲR1Ͳ1.13711CapitalImprovementSubtotal:215,291.00$CostFrequency(LS)(peryear)Dewatering: 10%$21,529.00Culvert: 1 50 LF$1.00 $50.00Mobilization: 5%$10,765.00Inlet:0 EA$52.00 $0.00TrafficControl: 10%$21,529.00Channel:1760 LF$2.00 $1,520.00UtilityCoordination: 10%$21,529.00Mowing: 1 0.17 ACRES $52.00 $9.00ErosionControl: 5%$10,765.00Trails:0 LF$5.00 $0.00AdditionalCostsSubtotal:$86,117.00MaintenanceCostsSubtotal:$1,579.00Engineering: 15%$45,211.00Legal/Administrative: 5%$15,070.00ConstructionMgmt: 10%$30,141.00Contingency: 25%$75,352.00OtherCostsSubtotal: $165,774.00TotalCapitalImprovementCost:467,182$TotalOperationandMaintenanceCostsOver50Years:33,920$ECͲR1Ͳ1.1UpperBearCreekParkGeneralInformationUpperBearCreekParkECͲR1Ͳ1.1760ProposedChannelModificationR1ͲReach1.12051219752(acres)(acres)BoulderEdging(LF)(acres)1493MaintenanceCosts%ofSubtotalQuantity Units UnitCost CostAdditionalCapitalImprovementCosts0.2230.0560.167CapitalImprovementCostSummarySiteCodeAreaDisturbedWetlandsPlantings ReclamationSeedingAttachment A: Bear Creek MItigation Plan
BearCanyonCreekFloodMitigationMasterPlanPreliminaryCostEstimateSiteCode:UDFCDCostingTab:ModelUSStation:ModelDSStation:ModelLength:Span: 28Removetwo8'S×4'RCBC'sspaced9feetoncenterRise: 7.5ExistingStructureLength: 191 LFNumberofBarrels: 1ExistingTotalStructureWidth: 17 ftLength: 191 LF/BarrelExistingStructureHeight: 4 ftWingwalls? Yes,atInletExistingStructureVolume: 12988ft3ProposedStructureVolume: 40110ft3ProposedVolumeIncrease=ProposedExcavationProposedExcavation: 1005 CYProposedStructureRemoval: 191 LF/BarrelExistingPavementRemoval: 20 SYProposedPavementThickness: 4 inProposedPavementWeight: 4.4 tonsPavementRemoveandReplace:1,078.00$($16.50/SYRemoved,$170/tonReplaced)CapitalImprovementSubtotal:646,746.00$CostFrequency(LS)(peryear)Dewatering: 10%$64,675.00Culvert: 1 191 LF$1.00 $191.00Mobilization: 5%$32,337.00Inlet:EA$52.00 $0.00TrafficControl: 10%$64,675.00Channel:LF$2.00 $0.00UtilityCoordination: 15%$97,012.00Mowing:ACRES $52.00 $0.00ErosionControl: 5%$32,337.00Trails:LF$5.00 $0.00AdditionalCostsSubtotal:$291,036.00MaintenanceCostsSubtotal:$191.00Engineering: 15%$140,667.00Legal/Administrative: 5%$46,889.00ConstructionMgmt: 10%$93,778.00Contingency: 25%$234,446.00OtherCostsSubtotal: $515,780.00TotalCapitalImprovementCost:1,453,562$TotalOperationandMaintenanceCostsOver50Years:4,103$CRͲR2Ͳ1.1LehighStreetCulvertGeneralInformationR2AͲReach1.117543LehighStreetCulvertCRͲR2Ͳ1.117352191CapitalImprovementCostSummaryAdditionalCapitalImprovementCostsMaintenanceCostsProposedCBCDesignProposedCulvertRemovalandExcavationTheproposeddimensionswerenotavailablefromtheCDOTM&SStandards,sotheproposedculvertwasinputastwo14'S×8'RCBCBarrelsforaninitialestimate.%ofSubtotalQuantityUnitsUnitCost CostProposedCrossingModificationBearCanyonCreekFloodMitigationMasterPlanPreliminaryCostEstimateSiteCode:UDFCDCostingTab:ModelUSStation:ModelDSStation:ModelLength:Mowing: 822 LFChannelModificationReach: 337 LF10ͲftͲWideTrail/Path: 0 LF10ͲftͲWideSidewalk: 0 LFBridges: 0Culverts: 0 LFExcavation(CY)ECͲR2Ͳ6.13024CapitalImprovementSubtotal:141,268.00$CostFrequency(LS)(peryear)Dewatering: 10%$14,127.00Culvert:0 LF$1.00 $0.00Mobilization: 5%$7,063.00Inlet:0 EA$52.00 $0.00TrafficControl: 10%$14,127.00Channel:1337 LF$2.00 $674.00UtilityCoordination: 10%$14,127.00Mowing: 1 0.09 ACRES $52.00 $5.00ErosionControl: 5%$7,063.00Trails:0 LF$5.00 $0.00AdditionalCostsSubtotal:$56,507.00MaintenanceCostsSubtotal:$679.00Engineering: 15%$29,666.00Legal/Administrative: 5%$9,889.00ConstructionMgmt: 10%$19,778.00Contingency: 25%$49,444.00OtherCostsSubtotal: $108,777.00TotalCapitalImprovementCost:306,552$TotalOperationandMaintenanceCostsOver50Years:14,586$ECͲR2Ͳ6.1StanfordAvenuetoHarvardLaneGeneralInformationR2AͲReach6.1214643StanfordAvenuetoHarvardLaneECͲR2Ͳ6.1CapitalImprovementCostSummaryAdditionalCapitalImprovementCostsMaintenanceCosts0.2138220.0530.160AreaDisturbedBoulderEdgingWetlandsPlantings ReclamationSeedingProposedChannelModification14306337%ofSubtotalQuantity Units UnitCost Cost(acres)(LF)(acres)(acres)SiteCodeAttachment A: Bear Creek MItigation Plan
BearCanyonCreekFloodMitigationMasterPlanPreliminaryCostEstimateSiteCode:UDFCDCostingTab:ModelUSStation:ModelDSStation:ModelLength:Span: 10Removetwo8'S×4.5'RCBC'sspaced9feetoncenterRise: 7.5ExistingStructureLength: 116 LFNumberofBarrels: 2ExistingTotalStructureWidth: 17 ftLength: 116 LF/BarrelExistingStructureHeight: 4 ftWingwalls? Yes,atInletandOutletExistingStructureVolume: 7888ft3ProposedStructureVolume: 17400ft3ProposedVolumeIncrease=ProposedExcavationProposedExcavation: 352 CYProposedStructureRemoval: 116 LF/BarrelExistingPavementRemoval: 20 SYProposedPavementThickness: 4 inProposedPavementWeight: 4.4 tonsPavementRemoveandReplace:1,078.00$($16.50/SYRemoved,$170/tonReplaced)CapitalImprovementSubtotal:316,393.00$CostFrequency(LS)(peryear)Dewatering: 10%$31,639.00Culvert: 1 232 LF$1.00 $232.00Mobilization: 5%$15,820.00Inlet:EA$52.00 $0.00TrafficControl: 10%$31,639.00Channel:LF$2.00 $0.00UtilityCoordination: 15%$47,459.00Mowing:ACRES $52.00 $0.00ErosionControl: 5%$15,820.00Trails:LF$5.00 $0.00AdditionalCostsSubtotal:$142,377.00MaintenanceCostsSubtotal:$232.00Engineering: 15%$68,816.00Legal/Administrative: 5%$22,939.00ConstructionMgmt: 10%$45,877.00Contingency: 25%$114,693.00OtherCostsSubtotal: $252,325.00TotalCapitalImprovementCost:711,095$TotalOperationandMaintenanceCostsOver50Years:4,984$CRͲR2Ͳ7.1HarvardLaneCulvertGeneralInformationHarvardLaneCulvertCRͲR2Ͳ7.1R2AͲReach7.114161CapitalImprovementCostSummaryAdditionalCapitalImprovementCostsMaintenanceCostsTheproposeddimensionswerenotavailablefromtheCDOTM&SStandards,sotheproposedculvertwasinputastwo10'S×8'RCBCBarrelsforaninitialestimate.TheproposedculvertisbrokenͲbacked;thiswasassumedtohaveminimaleffectoncostingandwasnotaddressedforcostestimatingpurposes.%ofSubtotalQuantityUnitsUnitCost Cost14045116ProposedCrossingModificationProposedCBCDesignProposedCulvertRemovalandExcavationBearCanyonCreekFloodMitigationMasterPlanPreliminaryCostEstimateSiteCode:UDFCDCostingTab:ModelUSStation:ModelDSStation:ModelLength:Span: 23Modify23'S×7.5'RCBCRise: 8.6ExistingStructureLength: 83 LFNumberofBarrels: 1ExistingTotalStructureWidth: 23 ftLength: 83 LF/BarrelExistingStructureHeight: 7.5 ftWingwalls? Yes,atInletandOutletExistingStructureVolume: 14317.5ft3ProposedStructureVolume: 16417.4ft3ProposedVolumeIncrease=ProposedExcavationProposedExcavation: 78 CYProposedStructureRemoval: 0 LF/BarrelCapitalImprovementSubtotal:30,000.00$CostFrequency(LS)(peryear)Dewatering: 10%$3,000.00Culvert: 1 83 LF$1.00 $83.00Mobilization: 5%$1,500.00Inlet:EA$52.00 $0.00TrafficControl: 10%$3,000.00Channel:LF$2.00 $0.00UtilityCoordination: 15%$4,500.00Mowing:ACRES $52.00 $0.00ErosionControl: 5%$1,500.00Trails:LF$5.00 $0.00AdditionalCostsSubtotal:$13,500.00MaintenanceCostsSubtotal:$83.00Engineering: 15%$6,525.00Legal/Administrative: 5%$2,175.00ConstructionMgmt: 10%$4,350.00Contingency: 25%$10,875.00OtherCostsSubtotal: $23,925.00TotalCapitalImprovementCost:67,425$TotalOperationandMaintenanceCostsOver50Years:1,783$CRͲR2Ͳ8.1BroadwayStreetCulvertGeneralInformationBroadwayStreetCulvertCRͲR2Ͳ8.1R2BͲReach8.1137911370883ProposedCrossingModificationProposedCBCDesignProposedCulvertRemovalandExcavationTheproposedculvertdesigndoesnotinvolvefullstructureremoval/replacement,justamodificationoftheculvertrise.Thisworkwasassumedtocostbetween$50,000and$100,000.CapitalImprovementCostSummaryAdditionalCapitalImprovementCostsMaintenanceCosts%ofSubtotalQuantity Units UnitCost CostAttachment A: Bear Creek MItigation Plan
BearCanyonCreekFloodMitigationMasterPlanPreliminaryCostEstimateSiteCode:UDFCDCostingTab:ModelUSStation:ModelDSStation:ModelLength:Mowing: 3967 LFChannelModificationReach: 1942 LF10ͲftͲWideTrail/Path: 0 LF10ͲftͲWideSidewalk: 0 LFBridges: 2Culverts: 0 LFExcavation(CY)ECͲR2Ͳ8.16275CapitalImprovementSubtotal:470,223.00$CostFrequency(LS)(peryear)Dewatering: 10%$47,022.00Culvert:0 LF$1.00 $0.00Mobilization: 5%$23,511.00Inlet:0 EA$52.00 $0.00TrafficControl: 10%$47,022.00Channel:11942 LF$2.00 $3,884.00UtilityCoordination: 15%$70,533.00Mowing: 1 0.46 ACRES $52.00 $24.00ErosionControl: 5%$23,511.00Trails:0 LF$5.00 $0.00AdditionalCostsSubtotal:$211,599.00MaintenanceCostsSubtotal:$3,908.00Engineering: 15%$102,273.00Legal/Administrative: 5%$34,091.00ConstructionMgmt: 10%$68,182.00Contingency: 25%$170,456.00OtherCostsSubtotal: $375,002.00TotalCapitalImprovementCost:1,056,824$TotalOperationandMaintenanceCostsOver50Years:83,952$ECͲR2Ͳ8.1BroadwaytoDartmouthGeneralInformationBroadwaytoDartmouthECͲR2Ͳ8.1R2BͲReach8.1213688117461942ProposedChannelModificationAreaDisturbedSiteCodeBoulderEdgingWetlandsPlantings ReclamationSeeding(acres)(LF)(acres) (acres)Cost0.401CapitalImprovementCostSummaryAdditionalCapitalImprovementCostsMaintenanceCosts0.53539670.134%ofSubtotalQuantity Units UnitCostBearCanyonCreekFloodMitigationMasterPlanPreliminaryCostEstimateSiteCode:UDFCDCostingTab:ModelUSStation:ModelDSStation:ModelLength:Span: 14Removetwo14'S×6'RCBC'sspaced15feetoncenterRise: 8.5ExistingStructureLength: 112 LFNumberofBarrels: 2ExistingTotalStructureWidth: 29 ftLength: 112 LF/BarrelExistingStructureHeight: 6 ftWingwalls? Yes,atInletandOutletExistingStructureVolume: 19488ft3ProposedStructureVolume: 26656ft3ProposedVolumeIncrease=ProposedExcavationProposedExcavation: 290 CYProposedStructureRemoval: 112 LF/BarrelExistingPavementRemoval: 46 SYProposedPavementThickness: 4 inProposedPavementWeight: 10.0 tonsPavementRemoveandReplace:2,459.00$($16.50/SYRemoved,$170/tonReplaced)CapitalImprovementSubtotal:422,033.00$CostFrequency(LS)(peryear)Dewatering: 10%$42,203.00Culvert: 1 224 LF$1.00 $224.00Mobilization: 5%$21,102.00Inlet:EA$52.00 $0.00TrafficControl: 10%$42,203.00Channel:LF$2.00 $0.00UtilityCoordination: 15%$63,305.00Mowing:ACRES $52.00 $0.00ErosionControl: 5%$21,102.00Trails:LF$5.00 $0.00AdditionalCostsSubtotal:$189,915.00MaintenanceCostsSubtotal:$224.00Engineering: 15%$91,792.00Legal/Administrative: 5%$30,597.00ConstructionMgmt: 10%$61,195.00Contingency: 25%$152,987.00OtherCostsSubtotal: $336,571.00TotalCapitalImprovementCost:948,519$TotalOperationandMaintenanceCostsOver50Years:4,812$CRͲR3Ͳ2.1R3AͲReach2.1CRͲR3Ͳ2.1US36CulvertGeneralInformationUS36CulvertTheproposeddimensionswerenotavailablefromtheCDOTM&SStandards,sotheproposedculvertwasinputastwo14'S×9'RCBCBarrelsforaninitialestimate.112ProposedCrossingModificationProposedCBCDesignProposedCulvertRemovalandExcavation1051210400CapitalImprovementCostSummaryAdditionalCapitalImprovementCostsMaintenanceCosts%ofSubtotalQuantity Units UnitCost CostAttachment A: Bear Creek MItigation Plan
BearCanyonCreekFloodMitigationMasterPlanPreliminaryCostEstimateSiteCode:UDFCDCostingTab:ModelUSStation:ModelDSStation:ModelLength:Mowing: 221 LFChannelModificationReach: 142 LF10ͲftͲWideTrail/Path: 0 LF10ͲftͲWideSidewalk: 0 LFBridges: 1Culverts: 0 LFExcavation(CY)ECͲR3Ͳ1.1110CapitalImprovementSubtotal:14,118.00$CostFrequency(LS)(peryear)Dewatering: 10%$1,412.00Culvert:0 LF$1.00 $0.00Mobilization: 5%$706.00Inlet:0 EA$52.00 $0.00TrafficControl: 10%$1,412.00Channel:1142 LF$2.00 $284.00UtilityCoordination: 10%$1,412.00Mowing: 1 0.03 ACRES $52.00 $2.00ErosionControl: 5%$706.00Trails:0 LF$5.00 $0.00AdditionalCostsSubtotal:$5,648.00MaintenanceCostsSubtotal:$286.00Engineering: 15%$2,965.00Legal/Administrative: 5%$988.00ConstructionMgmt: 10%$1,977.00Contingency: 25%$4,942.00OtherCostsSubtotal: $10,872.00TotalCapitalImprovementCost:30,638$TotalOperationandMaintenanceCostsOver50Years:6,144$ECͲR3Ͳ1.1R3AͲReach1.1ECͲR3Ͳ1.1US36toCDOTRightͲofͲWayGeneralInformationUS36toCDOTRightͲofͲWay142ProposedChannelModification1043510293AdditionalCapitalImprovementCostsMaintenanceCosts%ofSubtotalQuantity Units UnitCost Cost0.042840.0100.030CapitalImprovementCostSummarySiteCodeAreaDisturbedBoulderEdgingWetlandsPlantings ReclamationSeeding(acres)(LF)(acres)(acres)BearCanyonCreekFloodMitigationMasterPlanPreliminaryCostEstimateSiteCode:UDFCDCostingTab:ModelUSStation:ModelDSStation:ModelLength:Mowing: 3675 LFChannelModificationReach: 2004 LF10ͲftͲWideTrail/Path: 0 LF10ͲftͲWideSidewalk: 0 LFBridges: 1Culverts: 0 LFExcavation(CY)ECͲR3Ͳ2.116564CapitalImprovementSubtotal:704,673.00$CostFrequency(LS)(peryear)Dewatering: 10%$70,467.00Culvert:0 LF$1.00 $0.00Mobilization: 5%$35,234.00Inlet:0 EA$52.00 $0.00TrafficControl: 10%$70,467.00Channel:12004 LF$2.00 $4,008.00UtilityCoordination: 15%$105,701.00Mowing: 1 0.42 ACRES $52.00 $22.00ErosionControl: 5%$35,234.00Trails:0 LF$5.00 $0.00AdditionalCostsSubtotal:$317,103.00MaintenanceCostsSubtotal:$4,030.00Engineering: 15%$153,266.00Legal/Administrative: 5%$51,089.00ConstructionMgmt: 10%$102,178.00Contingency: 25%$255,444.00OtherCostsSubtotal: $561,977.00TotalCapitalImprovementCost:1,583,753$TotalOperationandMaintenanceCostsOver50Years:86,573$%ofSubtotalQuantity Units UnitCost CostSiteCodeAreaDisturbedBoulderEdgingWetlandsPlantings ReclamationSeeding(acres)(LF)(acres)(acres)0.53636750.1340.402CapitalImprovementCostSummaryAdditionalCapitalImprovementCostsMaintenanceCostsECͲR3Ͳ2.1CUCampusbetweenUS36andChurchPropertyGeneralInformationCUCampusbetweenUS36andChurchECͲR3Ͳ2.1R3AͲReach2.121044084362004ProposedChannelModificationAttachment A: Bear Creek MItigation Plan
BearCanyonCreekFloodMitigationMasterPlanPreliminaryCostEstimateSiteCode:UDFCDCostingTab:ModelUSStation:ModelDSStation:ModelLength:Mowing: 105 LFChannelModificationReach: 56 LF10ͲftͲWideTrail/Path: 0 LF10ͲftͲWideSidewalk: 0 LFBridges: 0Culverts: 0 LFExcavation(CY)ECͲR3Ͳ3.1677CapitalImprovementSubtotal:24,871.00$CostFrequency(LS)(peryear)Dewatering: 10%$2,487.00Culvert:0 LF$1.00 $0.00Mobilization: 5%$1,244.00Inlet:0 EA$52.00 $0.00TrafficControl: 10%$2,487.00Channel:156 LF$2.00 $112.00UtilityCoordination: 15%$3,731.00Mowing: 1 0.01 ACRES $52.00 $1.00ErosionControl: 5%$1,244.00Trails:0 LF$5.00 $0.00AdditionalCostsSubtotal:$11,193.00MaintenanceCostsSubtotal:$113.00Engineering: 15%$5,410.00Legal/Administrative: 5%$1,803.00ConstructionMgmt: 10%$3,606.00Contingency: 25%$9,016.00OtherCostsSubtotal: $19,835.00TotalCapitalImprovementCost:55,899$TotalOperationandMaintenanceCostsOver50Years:2,427$ECͲR3Ͳ3.1ChurchPropertyUSofDrivewayGeneralInformationChurchPropertyUSofDrivewayECͲR3Ͳ3.1R3AͲReach3.18484842856ProposedChannelModificationSiteCodeAreaDisturbed%ofSubtotalQuantity Units UnitCost Cost(acres)(acres)0.0181000.0050.014CapitalImprovementCostSummaryBoulderEdgingWetlandsPlantings ReclamationSeeding(acres)(LF)AdditionalCapitalImprovementCostsMaintenanceCostsBearCanyonCreekFloodMitigationMasterPlanPreliminaryCostEstimateSiteCode:UDFCDCostingTab:ModelUSStation:ModelDSStation:ModelLength:Removetwo5.67'S×3.58'RellipticalculvertpipesExistingStructureLength: 40 LFExistingTotalStructureWidth: 12.5 ftExistingStructureHeight: 3.58 ftExistingStructureVolume: 1790ft3ProposedStructureVolume: 0ft3ExistingStructureVolume=ProposedExcavationProposedExcavation: 67 CYProposedStructureRemoval: 80 LFExistingPavementRemoval: 6 SYProposedPavementThickness: 4 inProposedPavementWeight: 1.4 tonsPavementRemoveandReplace:337.00$($16.50/SYRemoved,$170/tonReplaced)CapitalImprovementSubtotal:219,435.00$CostFrequency(LS)(peryear)Dewatering: 10%$21,944.00Culvert: 1 80 LF$1.00 $80.00Mobilization: 5%$10,972.00Inlet:EA$52.00 $0.00TrafficControl: 10%$21,944.00Channel:LF$2.00 $0.00UtilityCoordination: 15%$32,915.00Mowing:ACRES $52.00 $0.00ErosionControl: 5%$10,972.00Trails:LF$5.00 $0.00AdditionalCostsSubtotal:$98,747.00MaintenanceCostsSubtotal:$80.00Engineering: 15%$47,727.00Legal/Administrative: 5%$15,909.00ConstructionMgmt: 10%$31,818.00Contingency: 25%$79,546.00OtherCostsSubtotal: $175,000.00TotalCapitalImprovementCost:493,182$TotalOperationandMaintenanceCostsOver50Years:1,719$CRͲR3Ͳ5.1ChurchDrivewayCulvertGeneralInformationChurchDrivewayCulvertCRͲR3Ͳ5.1R3BͲReach5.18428838840ProposedCrossingModificationProposedBridgeDesignProposedCulvertRemovalandExcavationThechurchdrivewaycrossingwillbeexpandedtospanabout40feetoverBearCanyonCreek.Thisalternativemaybeabridgecrossing,butthedesignisyettobedetermined.Forpreliminarycostingpurposes,thiscrossingwasmodeledastwo20'S×8'RCBC's.AdditionalCapitalImprovementCostsMaintenanceCostsUnitCost Cost%ofSubtotalQuantity UnitsCapitalImprovementCostSummaryAttachment A: Bear Creek MItigation Plan
BearCanyonCreekFloodMitigationMasterPlanPreliminaryCostEstimateSiteCode:UDFCDCostingTab:ModelUSStation:ModelDSStation:ModelLength:Mowing: 84 LFChannelModificationReach: 94 LF10ͲftͲWideTrail/Path: 0 LF10ͲftͲWideSidewalk: 0 LFBridges: 0Culverts: 80 LF(DoubleͲBarrel)Excavation(CY)ECͲR3Ͳ3.2658CapitalImprovementSubtotal:23,235.00$CostFrequency(LS)(peryear)Dewatering: 10%$2,324.00Culvert: 1 80 LF$1.00 $80.00Mobilization: 5%$1,162.00Inlet:0 EA$52.00 $0.00TrafficControl: 10%$2,324.00Channel:194 LF$2.00 $188.00UtilityCoordination: 15%$3,485.00Mowing: 1 0.01 ACRES $52.00 $1.00ErosionControl: 5%$1,162.00Trails:0 LF$5.00 $0.00AdditionalCostsSubtotal:$10,457.00MaintenanceCostsSubtotal:$269.00Engineering: 15%$5,054.00Legal/Administrative: 5%$1,685.00ConstructionMgmt: 10%$3,369.00Contingency: 25%$8,423.00OtherCostsSubtotal: $18,531.00TotalCapitalImprovementCost:52,223$TotalOperationandMaintenanceCostsOver50Years:5,779$ECͲR3Ͳ3.2ChurchPropertyDSofDrivewayGeneralInformationChurchPropertyDSofDrivewayECͲR3Ͳ3.2R3BͲReach3.28428833494ProposedChannelModificationWetlandsPlantings ReclamationSeedingSiteCodeAreaDisturbedBoulderEdging(acres)(LF)%ofSubtotalQuantity(acres)AdditionalCapitalImprovementCostsMaintenanceCosts0.031840.0080.023(acres)CapitalImprovementCostSummaryUnits UnitCost CostBearCanyonCreekFloodMitigationMasterPlanPreliminaryCostEstimateSiteCode:UDFCDCostingTab:ModelUSStation:ModelDSStation:ModelLength:Span: 28Removetwo12'S×7'RCBC'sspaced15feetoncenterRise: 7.5ExistingStructureLength: 186 LFNumberofBarrels: 2ExistingTotalStructureWidth: 25 ftLength: 186 LF/BarrelExistingStructureHeight: 7 ftWingwalls? Yes,atInletandOutletExistingStructureVolume: 32550ft3ProposedStructureVolume: 78120ft3ProposedVolumeIncrease=ProposedExcavationProposedExcavation: 1688 CYProposedStructureRemoval: 186 LF/BarrelExistingPavementRemoval: 47 SYProposedPavementThickness: 4 inProposedPavementWeight: 10.2 tonsPavementRemoveandReplace:2,510.00$($16.50/SYRemoved,$170/tonReplaced)CapitalImprovementSubtotal:CostFrequency(LS)(peryear)Dewatering: 10%$121,426.00Culvert: 1 372 LF$1.00 $372.00Mobilization: 5%$60,713.00Inlet:EA$52.00 $0.00TrafficControl: 10%$121,426.00Channel:LF$2.00 $0.00UtilityCoordination: 15%$182,139.00Mowing:ACRES $52.00 $0.00ErosionControl: 5%$60,713.00Trails:LF$5.00 $0.00AdditionalCostsSubtotal:$546,417.00MaintenanceCostsSubtotal:$372.00Engineering: 15%$264,101.00Legal/Administrative: 5%$88,034.00ConstructionMgmt: 10%$176,068.00Contingency: 25%$440,169.00OtherCostsSubtotal: $968,372.00TotalCapitalImprovementCost:2,729,048$TotalOperationandMaintenanceCostsOver50Years:7,991$CRͲR3Ͳ6.1BaselineRoadCulvertGeneralInformationBaselineRoadCulvertCRͲR3Ͳ6.1R3BͲReach6.1AdditionalCapitalImprovementCostsMaintenanceCosts%ofSubtotalQuantity Units UnitCost CostTheproposeddimensionswerenotavailablefromtheCDOTM&SStandards,sotheproposedculvertwasinputasfour14'S×8'RCBCBarrelsforaninitialestimate.80137827186ProposedCrossingModificationProposedCBCDesignProposedCulvertRemovalandExcavationCapitalImprovementCostSummary$1,214,259.00Attachment A: Bear Creek MItigation Plan
BearCanyonCreekFloodMitigationMasterPlanPreliminaryCostEstimateSiteCode:UDFCDCostingTab:ModelUSStation:ModelDSStation:ModelLength:Mowing: 807 LFChannelModificationReach: 613 LF10ͲftͲWideTrail/Path: 0 LF10ͲftͲWideSidewalk: 345 LFBridges: 1Culverts: 51 LFExcavation(CY)ECͲR3Ͳ7.1330CapitalImprovementSubtotal:48,810.00$CostFrequency(LS)(peryear)Dewatering: 10%$4,881.00Culvert: 1 51 LF$1.00 $51.00Mobilization: 5%$2,441.00Inlet:0 EA$52.00 $0.00TrafficControl: 10%$4,881.00Channel:1613 LF$2.00 $1,226.00UtilityCoordination: 10%$4,881.00Mowing: 1 0.09 ACRES $52.00 $5.00ErosionControl: 5%$2,441.00Trails: 1 345 LF$5.00 $1,725.00AdditionalCostsSubtotal:$19,525.00MaintenanceCostsSubtotal:$3,007.00Engineering: 15%$10,250.00Legal/Administrative: 5%$3,417.00ConstructionMgmt: 10%$6,834.00Contingency: 25%$17,084.00OtherCostsSubtotal: $37,585.00TotalCapitalImprovementCost:102,138.00$TotalOperationandMaintenanceCostsOver50Years:64,597.00$(LF)(acres) (acres)ECͲR3Ͳ7.1NearGilpinAdditionalCapitalImprovementCostsMaintenanceCosts%ofSubtotalQuantity Units UnitCost Cost0.2985200.0750.224CapitalImprovementCostSummary78337220613ProposedChannelModificationSiteCodeAreaDisturbedBoulderEdgingWetlandsPlantings ReclamationSeeding(acres)NOTE:TheGilpinculvertmayberemoved.Thisanalysisassumestheculvertisstillinplaceduringchannelmodifications.GeneralInformationBaselineRoadtoNorthofGilpinECͲR3Ͳ7.1R3BͲReach7.12BearCanyonCreekFloodMitigationMasterPlanPreliminaryCostEstimateSiteCode:UDFCDCostingTab:ModelUSStation:ModelDSStation:ModelLength:Span: 20Remove20'S×7'RCBCRise: 8ExistingStructureLength: 51 LFNumberofBarrels: 2ExistingTotalStructureWidth: 20 ftLength: 51 LF/BarrelExistingStructureHeight: 7 ftWingwalls? NoExistingStructureVolume: 7140ft3ProposedStructureVolume: 16320ft3ProposedVolumeRemoval=ProposedExcavationProposedExcavation: 264 CYProposedStructureRemoval: 51 LF/BarrelExistingPavementRemoval: 39 SYProposedPavementThickness: 4 inProposedPavementWeight: 8.5 tonsPavementRemoveandReplace:2,089.00$($16.50/SYRemoved,$170/tonReplaced)CapitalImprovementSubtotal:349,108.00$CostFrequency(LS)(peryear)Dewatering: 10%$34,911.00Culvert: 1 102 LF$1.00 $102.00Mobilization: 5%$17,455.00Inlet:EA$52.00 $0.00TrafficControl: 10%$34,911.00Channel:LF$2.00 $0.00UtilityCoordination: 15%$52,366.00Mowing:ACRES $52.00 $0.00ErosionControl: 5%$17,455.00Trails:LF$5.00 $0.00AdditionalCostsSubtotal:$157,098.00MaintenanceCostsSubtotal:$102.00Engineering: 15%$75,931.00Legal/Administrative: 5%$25,310.00ConstructionMgmt: 10%$50,621.00Contingency: 25%$126,552.00OtherCostsSubtotal: $278,414.00TotalCapitalImprovementCost:784,620$TotalOperationandMaintenanceCostsOver50Years:2,191$ProposedCBCDesignProposedCulvertRemovalandExcavationCapitalImprovementCostSummaryAdditionalCapitalImprovementCostsMaintenanceCosts%ofSubtotalQuantity Units UnitCost CostCRͲR3Ͳ7.1GilpinDriveCulvertGeneralInformationGilpinDriveCulvertCRͲR3Ͳ7.1R3BͲReach7.17471742051ProposedCrossingModificationAttachment A: Bear Creek MItigation Plan
ATTACHMENT B: General Public Comments and Responses
General Theme Response
Storm sewer outfall
issues
Storm sewer outfalls have been identified at Bear Creek Condominiums,
Ithaca Drive and Gilpin Drive. Recommendations for reconfiguration are
included in the final mitigation plan document.
Sanitary sewer
backup in Frasier
Meadows
neighborhood
The sanitary and storm sewer system in Frasier Meadows neighborhood is
complex. The area was historically used for farming and agriculture, has
shallow groundwater and is topographically lower than surrounding areas.
The neighborhood has potential connection to Bear Canyon Creek via an
inlet located on CU property (a historical natural spring that was used to fill
Thunderbird lake). It is believed that by containing the 100-year floodplain
within the channel on CU property, flows from the creek will not enter the
Frasier Meadows neighborhood at this location.
Construction timeline
is too long
Some recommended improvements will undergo public process during the
design phase which can include; a Community and Environmental
Assessment Process (CEAP), input and recommendation from the WRAB,
input and recommendation from other advisory boards such as Planning
Board, and City Council. This process can take time for design to be fully
approved, at which point funding for construction can be pursued. There
may be opportunity for collaborative funding efforts with transportation
projects, the University of Colorado or FEMA.
Inadequate funding
Remove steel culvert
at Ithaca Drive
Included in recommended improvements.
Do not decrease
traffic lanes on Table
Mesa Drive
The recommended improvements increase capacity at the Lehigh Street and
Harvard Lane culverts without altering the number of traffic lanes on Table
Mesa Drive. This approach reduces flows in the roadway and would not
increase vehicular congestion to and from Bear Creek Elementary School.
Increase capacity at
Saint Andrew Church
driveway
Included in recommended improvements.
Do not remove
habitat, vegetation
and trees
Increased channel capacity can sometimes require removal of vegetation
and trees, but it is also essential to the success of the recommended
improvements. Every effort will be made to protect the natural habitat
during design and construction of the recommended improvements. Remove trees and
vegetation
Deepen the channel
Provide a concrete
lined channel
Concrete lined channels technically stabilize against erosion, but would not
work to create natural streams and well-vegetated floodplains that are
physically and biologically healthy. Concrete lined channels remove
vegetation and habitat, increase flow velocity and can create negative
impacts to property and habitat downstream.
Attachment B: General Public Comments
ATTACHMENT C: Initial Scope of Flood Mitigation Analysis
Attachment C: Initial Scope of Flood Mitigation Analysis
ATTACHMENT D: Existing Conditions FLO-2D and Current Floodplain
Attachment D: Existing Conditions and Current Floodplain
CITY OF BOULDER
WATER RESOURCES ADVISORY BOARD
AGENDA ITEM
MEETING DATE: October 17, 2016
AGENDA TITLE: Information Item - Next Steps Related to Phase 2 Analysis for the
Utility Rate Study
PRESENTER/S
Jeff Arthur, Director of Public Works for Utilities
Ken Baird, Utilities Financial Manager
Eric M. Ameigh, Public Works Projects Coordinator
PURPOSE
The purpose of this item is to follow up on the August and September 2016 WRAB discussions
related to the Utility Rate Study Phase 1 analysis and confirm support for the proposed water rate
structure alternatives to be studied in Phase 2.
Through the August and September discussions, WRAB provided feedback related to Phase 1
findings. This included generally affirming the key findings related to each of the three utility
rate structures. Areas of discussion included Commercial, Industrial, Institutional (CII) water
budgets, the residential indoor water budget allocation, the fixed-service charge in the
wastewater fee, and alternative calculations for the stormwater/flood management fee.
In September, WRAB expressed support for studying rate structure alternatives in the
wastewater and stormwater/flood management utilities. Staff also sought and received additional
feedback related to issues in the water rate structure which assisted in the development of
alternatives for study. Those water rate structure alternatives are described in this memo.
BACKGROUND
WRAB has received regular memos about the project since early 2015. A full project
background can be found in the August 2016 meeting packet.
In 2014, Utilities Division staff met with customers to better understand the impacts of proposed
2015 utility rate increases. Many customers indicated they did not understand utility rate
structures and/or had questions and concerns about the calculation of the charges on their utility
bills. These findings, along with the fact that regular review of rate structures is an accepted best
practice, led staff to propose an evaluation of the rate structure and associated calculations for
water, wastewater, and stormwater/flood management utilities as part of the 2015 work plan.
Staff implemented a public engagement process in spring of 2015 and WRAB endorsed utility
guiding principles and the project’s areas of study at the June 2015 meeting. Based on WRAB
feedback and guidance related to guiding principles and areas of study, staff developed a scope
of work for the analysis phase of the project. The scope of work informed a request for
Agenda Item 5 Page #1
consultant proposals (RFP) which was issued in early November 2015. Raftelis Financial
Consultants (RFC) was selected to assist with the project.
The analysis component of the project is roughly divided into three phases, as follows:
Phase 1 – Investigation and Assessment
Phase 2 – Analysis of Potential Alternatives
Phase 3 – Recommendations
At the August 2016 WRAB meeting, consultants from RFC presented their preliminary findings,
the most significant of which are outlined below at a summary level.
Water Utility, including Water Budgets
RFC identified the following five key issues relative to the existing water utility rate structure.
1. Water budget rate structures do not work well for diverse commercial, industrial and
institutional (CII) customers.
2. Blocks 1 and 2 could be combined into a single block to provide for more consistent
monthly water budgets. Alternatively, a modified definition could be applied where, quite
simply, block 1 is defined as the indoor budget and block 2 as the outdoor budget.
3. Residential indoor water allocations exceed recent indoor water use.
4. Reliance on revenue generated in Blocks 3, 4 and 5 results in a level of revenue instability
that could adversely impact utility operations.
5. Block width and block pricing may not be aligned with City pricing objectives.
Wastewater Utility
RFC identified the following two key issues relative to the existing wastewater utility rate
structure.
1. Revenue insufficiency due to:
a. declining volume sales and
b. amount of revenue recovered through monthly service charge.
2. Industrial Pre-Treatment fees do not recover the costs incurred.
Stormwater/Flood Management Utility
RFC identified the following two key issues relative to the existing stormwater utility rate
structure.
1. Non-single family rate structure is unnecessarily complex.
2. The current rate structure penalizes individual large lot customers.
At its September 2016 meeting, WRAB expressed support for studying rate structure alternatives
in the wastewater and stormwater/flood management utilities. More information on those
alternatives can be found in the September 2016 memo. Staff also sought and received additional
feedback related to issues in the water rate structure which assisted in the development of
alternatives for study, as described in the following section.
Agenda Item 5 Page #2
ANALYSIS
The goal of Phase 1 is to determine which alternatives should be investigated for each of the
three utilities during Phase 2. At the August meeting, a consensus appeared to emerge for how to
proceed with studying alternatives for stormwater/flood management and wastewater. Due to a
lack of time, however, the discussion of key issues in the water rate structure did not result in a
similarly clear consensus. At the subsequent WRAB meeting, staff sought and received
additional board feedback on water rate structure issues, which led to the development of a
proposed list of options to study.
CII Water Budgets
At the August WRAB discussion, RFC presented information related to the issues with assigning
water budgets to the city’s CII customers. CII customers traditionally experience much higher
usage in Blocks 3,4, and 5, which represents out of budget use, than do residential customers and
therefore effectively pay a higher unit cost for water than residential customers. A higher unit
cost indicates that CII customers are inherently less efficient than residential customers but there
is no evidence that this is the case in reality.
Variations of use from budget are not uncommon in the CII customer class. Around 30% of CII
customers in 2015 had annual usage at less than half of their water budget, and 13% had usage of
more than one and one-half times their budget. This variation is not seen in residential
customers, for which indoor and outdoor water usage patterns are relatively well understood. The
manner in which CII water budgets have been set appears to have caused some customers to be
charged in the upper rate tiers and others to be charged only at the discounted block one rate.
These outcomes should occur only if customers are either inefficient water users or very efficient
users, respectively. But, it is not clear that all CII water budgets are accurate and thus the
determination of efficiency may also be inaccurate. If this is the case, there is a potential equity
imperative for addressing the issue of CII water budgets.
The rate structure discourages wasteful use by sending a price signal when a customer exceeds
the budget. However, the annual trends show usage in the upper blocks has stayed fairly
consistent over the years and correlates strongly with the weather with little evidence of behavior
change due to pricing. CII customers also have the option of changing how their water budget is
calculated, but relatively few have taken advantage of this option.
Two conclusions may be drawn from these findings: first, some substantial portion of CII
customers are not heeding the price signal and second, their budgets are likely not properly set,
making the price signal unclear even it is received.
Residential Indoor Water Budgets
The preliminary analysis clearly showed that the average residential customer, both for single
family and multifamily, uses far less than the base allocations of 7,000 and 4,000 gallons
respectively. The original single family allocation was established with an assumption of a four-
person household, a per capita usage of approximately 55 gallons per day, and some winter
outdoor watering needs. Over time, however, indoor water use has steadily declined but the base
allocation has not been adjusted downward to align with the new reality. As a result, the lowest
priced water, which is meant for regular indoor needs, has been able to be used for outdoor
Agenda Item 5 Page #3
watering. This has undermined the price signal effect and potentially decreased the conservation
impact of water budgets.
Options for Addressing Issues in Water Rate Structure
There was general consensus at the September 2016 WRAB meeting that staff and RFC should
develop and evaluate options to address issues with CII water budgets and residential indoor
water budgets. In all cases, alternatives should focus on the established guiding principles,
including revenue stability, equity, and conservation. Alternatives proposed to be studied include
the following:
Update the fixed service charge for 2017.
o The cost basis for the fixed charge will be updated with the most recent
information.
Move all CII customers currently using the Average Monthly Use (AMU) water budget
option to the Indoor/Outdoor option.
o Many of the issues discovered in CII water budgets are related to the AMU
option, which requires frequent updates to remain accurate.
o The Indoor/Outdoor option, which uses average winter consumption (AWC) as a
basis for calculating indoor budgets, is more responsive in measuring actual use
and is self-updating over time.
o All customers who have made a choice to use the Historical Monthly Use (HMU)
water budget option would remain under the HMU option.
Combine Blocks 1 and 2.
o The blocks would be combined and redefined as “in budget” use.
o The new block would be adjusted seasonally to more accurately account for
current indoor and outdoor use.
o This combination would make the system simpler while still allowing for seasonal
flexibility related to outdoor watering needs.
Reduce the residential indoor allocation
o The indoor allocations for single-family (SFR) and multi-family residential
(MFR) customers will be decreased to reflect current water usage patterns and
preserve a price signal for conservation.
o The current allocation for SFR is 7,000 gallons per month. RFC will test the
impacts of decreasing it to both 6,000 and 5,000 gallons.
o The current allocation for MFR is 4,000 gallons per month. RFC will test the
impacts of decreasing it to 3,000 gallons.
Update basis for pricing tiers and multipliers and adjust accordingly.
o Tiers are the percentage thresholds of budget use that push usage from one block
into another (e.g. using 151% of one’s budget instead of 150% moves usage from
Block 3 into Block 4).
Agenda Item 5 Page #4
o Multipliers are the differences in price per 1,000 gallons between the blocks (e.g.
Block 3 usage is charged at twice the base rate while Block 4 usage is charged at
three times the base rate).
o Tiers and multipliers will be updated to better reflect the city’s pricing objectives,
as reflected in the guiding principles.
The alternatives will be analyzed in different combinations to create scenarios. Within all the
alternatives and scenarios, RFC will also calculate customer bill impacts. The analysis of bill
impacts will examine the following:
Shifts in costs within a class and also between classes. Because total revenue
requirements remain largely the same, a decrease in price for one customer must be made
up by other customers.
Potential impact on highly efficient users. It is possible that the combination of Blocks 1
and 2 could affect the incentive for very efficient users.
Potential impacts on lower-income customers will be evaluated. It is possible that the
combination of Blocks 1 and 2 could increase the price for what is currently the least
expensive water.
To the extent any of these issues do arise in the modeling of alternatives, staff and RFC will
present pros and cons along with potential mitigation strategies. For example, staff may explore
programmatic possibilities for low income water users who could be affected.
Additional Areas of Study
At the September meeting, WRAB expressed some interest in pursuing additional related lines of
inquiry that fall outside the scope of the current study. One of these topics is how behavioral
economics might be better utilized in the water utility’s customer communications in order to
positively impact conservation. WRAB and staff are following up to determine next steps on the
idea, including a discussion at the WRAB retreat later this year.
Staff is also seeking further comment and insight from RFC on other rate structure ideas that
have been proposed through the board’s discussions. The expert feedback from the city’s
consultant will help inform future WRAB conversations. Longer term thinking about
fundamental changes to the rate structures, instead of modifications to the current structures,
could result in new projects in future years. If WRAB is interested in pursuing new rate structure
ideas over time, the board’s retreat would be a venue to discuss potential future efforts.
NEXT STEPS
December – Staff and RFC will present WRAB with the results of the Phase 2 analysis related to
wastewater and stormwater/flood management and seek feedback on which rate structure
adjustments to refine for final recommendation.
Agenda Item 5 Page #5
January 2017 – Staff and RFC will present WRAB with the results of the Phase 2 analysis
related to the water rate structure and seek feedback on which rate structure adjustments to refine
for final recommendation.
February 2017 – The final report and recommendations will be presented to WRAB for final
feedback and recommendation to City Council. Depending on WRAB’s recommendations, staff
will evaluate the necessary next steps. If the recommendations fundamentally alter any of the
rate structures, there could be a need for additional public process, customer outreach, and
consultation with City Council. An analysis of implementation needs could also be required.
March 2017 – Staff will present project results, WRAB recommendations, and implementation
next steps to City Council for their consideration.
ATTACHMENTS
None
Agenda Item 5 Page #6
INFORMATION PACKET
MEMORANDUM
To: Members of the Water Resource Advisory Board
From: Jeff Arthur, Director of Public Works for Utilities
Joe Taddeucci, Water Resources Manager
Bret Linenfelser, Water Quality Environmental Services Manager
Russ Sands, Watershed Sustainability and Outreach Supervisor
MaryAnn Nason, Water Conservation and Outreach Coordinator
Date: October 17, 2016
Subject: 2016 Water Efficiency Plan Update
EXECUTIVE SUMMARY:
This memorandum summarizes the City of Boulder’s (city) state mandated 2016 Water Efficiency Plan
(WEP) update which was submitted to WRAB with the September 19, 2016 meeting packet. As no
comments were received, the unchanged WEP (Attachment A) will be used to launch the official
commencement of the state-required 60-day WEP public comment period starting at the October 17, 2016
WRAB meeting. The WEP will be available to the public through www.BoulderSavesWater.net and the
Boulder Public Main Library and the public will be notified through online or print advertisements. Once
the public comment period closes, staff will submit the WEP, with any comments received, to the state to
meet the December 2016 deadline.
Per state requirements to update the WEP every seven years and include specific elements, the WEP
details the city’s historical treated water use, current water efficiency efforts and existing long-term goals.
The 2016 WEP recommends the city maintain its existing water conservation goals as part of a “no
regrets” planning strategy especially as concurrent projects like the 2016 Rate Study and Boulder Creek
Climate model updates may significantly shape long-term water conservation planning goals.
Ultimately, the city’s responsibility is to submit an efficiency plan that conforms to the state’s
requirements, and the state has given a preliminary indication that the 2016 WEP will be satisfactory
based on a cursory review of a draft. Since completion of the previous plan in 2009, staff have checked-
in with WRAB a number of times on water conservation initiatives, most recently at the January 2016
WRAB meeting. Water conservation planning, goals and major recommendations in the 2016 WEP are
reflective of WRAB’s input to date.
BACKGROUND:
The Water Conservation Program (WCP) was created in 1992 with WCP efforts originally directed at
reducing peak demand and developing long-term sustainability goals. From 1992 to 2000, water use
increased significantly with the highest use occurring in 2000. In response, the city developed the 2000
Water Conservation Futures Study (WCFS) which set a program goal of reducing total city water use at
buildout by 10% with a WCP (or 20% without a WCP) as compared to the 1994 to 1996 baseline.1
The 2002 to 2003 drought (among the worst on record in Colorado) marked a stark change in both city
and state water policies that would have significant and lasting impacts on customer water use and the
role of the WCP. Most immediately, watering restrictions and surcharges played a role in altering
customer behavior. However, lasting impacts from the drought also affected policy. The drought spurred
the completion of the city’s Drought Plan (2002), embedded water conservation efforts into utility
planning, integrated climate impacts into water demand forecasting (beginning in 2003) and led to the
approval of a 5-tier inclining block rate, water budget structure (implemented in 2007).
At the state level, the drought triggered the Colorado Water Conservation Board (CWCB) to develop and
pass the 2004 Water Conservation Act. This required, among other things, municipalities to develop a
state approved Water Conservation Plan (now called a Water Efficiency Plan) every seven years that must
contain a list of specific elements. These include a profile of existing water supply systems, historical and
future water demands, water efficiency activities and monitoring of these efforts. The city submitted and
received approval from the CWCB for the original plan in 2009 with the first WEP update due in 2016.
In 2011, the Water Utilities Master Plan (WUMP) Volume 2 identified that the city’s water conservation
goals had largely been met but promoted the continuation of the WCP with several recommendations
including an evaluation of program activities and leveraging resources. Acting on WUMP
recommendations, WCP staff replaced the traditional rebate program with a service-oriented approach
that allowed for greater leveraging of resources with larger sustainability initiatives (e.g. building on the
water-energy nexus) and improved customer service.
More recently, the WCP merged with utility outreach, stormwater quality and inflow and infiltration
mitigation programs to create the Watershed Sustainability & Outreach Program. This has allowed for
enhanced community engagement, integration of WRAB supported efforts to better merge flood and
drought response planning and continues to leverage larger city sustainability and resilience initiatives.
A summary of these most recent WCP activities and other efficiency planning efforts have been
incorporated into the city’s 2016 WEP (see Attachment A). This information was provided to WRAB
with the September 19, 2016 WRAB meeting packet and no comments were received.
ANALYSIS:
The 2016 WEP update follows the CWCB’s Water Efficiency Plan Municipal Guide requirements. This
includes a history of the city’s efficiency planning efforts and historical water demands which have
consistently remained below 2000 water use levels due to a variety of reasons (efficient appliances, block
rates; etc.). However, the WEP also focuses on future water demand forecasting, community trends and
WCP recommendations to address projected increases in water use moving forward.
Drivers That Can Increase Water Use
1 Meeting the WCFS goal would result in 21,690 acre feet or less water use at the then, 2025 buildout.
Increases in future water use are largely due to the following key drivers:
-Demographic and Land Use Projections: Boulder’s projections anticipate an increase in population,
employment and density by 2040 which will increase total water use.
-Climate Change Effects on Project Water Demands: There is general consensus that temperatures are
expected to increase in the future which will likely increase outdoor water use.
-Natural Replacement of Fixtures: Efficient appliance and fixture technology, regulation and remodeling
continues to reduce indoor water in the near-term, but as the population grows and the volume of new
appliances and fixtures increase, long-term projections for indoor water use will increase slightly even if
fixtures and appliances are more efficient.
As a result of the drivers above, maintaining existing WCP efforts are important to advancing
conservation activities and behavior trends. Although there are many educational activities for which it is
difficult to directly attribute water savings, WCP program tracking efforts confirm that service-based
efforts have actively saved approximately 15 acre foot each year.
Projected Water Use and No Regrets Strategy
The combination of the drivers noted above indicate Boulder’s total treated water demand will remain at
current conditions in the short-term, but will likely increase overtime as shown in Figure 1.2 Although the
WCP and other current efficiency practices can meet this near-term demand, the city will need to be
strategic in how it plans to meet its future demands. This is largely because the extent to which any one
driver may impact future demand cannot be said with certainty. In fact, the WEP shows how future water
use could vary by almost 6,000 acre-feet depending on how much factors like climate change influence
water use.
Figure 1: Historical and Projected Demand
2 Climate change impacts have been disaggregated into three outcomes to best reflect the range of climate model
results.
23,717
19,980
23,908
20,997
18,171
16,000
17,000
18,000
19,000
20,000
21,000
22,000
23,000
24,000
25,000
1990 2000 2010 2020 2030 2040 2050 2060 2070 2080Historical Use/Projected Demand (AF)Projected demand with existing (2012-2015 average) per capita use factors
Projected demand with conservation and natural replacement
Projected demand with conservation, natural replacement & climate change (maximum of model results)
Projected demand with conservation, natural replacement & climate change (average of modeled results)
Projected demand with conservation, natural replacement & climate change (minimum of modeled results)
Historical use
Projected demand, WCFS Comprehensive Scenario (did not address climate change)
residential zoning capacity assumed to be reached by 2040
savings from active conservation and natural replacment assumed to reach 100% by 2050
non-residential zoning capacity assumed to be reached by 2078
Following the state’s direction in the Colorado Water Plan, the WEP is using a “no regrets” approach to
evaluating the range of future projections (or scenarios). No regrets strategies are justifiable near-term
actions that make sense under any future scenario from an economic, social and environmental
perspective. Taking a no regrets planning approach for the current WEP allows the city to sustain it’s
existing water conservation goals while monitoring trends and new information that can be used to inform
whether new goals should be set prior to the 2023 WEP update. Any new goals the city would decide to
establish will almost certainly be impacted by other projects the city is currently engaged in that stand to
shape its water conservation goals.
Other Projects That Will Influence Water Conservation Planning
It is important for the WCP to factor in the outcomes of a number of ongoing city efforts prior to setting
any new goals. These include:
-Boulder Creek Climate Model Updates will provide greater granularity and enhance climate projections
that can be used to recalculate water use projections shown in the WEP.
-Revisions to the Green Points Program in 2017, designed to encourage the use of sustainable
technologies via the new-construction and remodeling permit application process, may result in more
stringent water conservation requirements for both indoor and outdoor.
-Completion of the 2016 Rate Study may result in changes to the current billing and water budget system
that could ultimately have an impact on customer behavior with water use.
-Energy Utility Municipalization offers an opportunity to potentially upgrade city water meters with an
integrated metering and billing system that could provide real-time water (and energy) data which could
help reduce water loss.
Each of the items listed above are all expected to be completed prior to the next WEP update in 2023.
Results from these activities will provide the information needed to decide if new city water conservation
goals should be developed.
Maintaining Current Water Conservation Goals
The city has met all water conservation goals in each customer sector except for non-revenue water, also
known as water loss (see Table 1). After reviewing water use trends, water demand drivers and projected
water use, the city has determined that the current water conservation goals represent a no regret planning
strategy which allows the city to continue meeting short-term water demand goals. New water
conservation goals will be evaluated as part of the WEP update in 2023.
Table 1: Status of Boulder’s Attainment of its Water Conservation Goal
WEP Recommendations
In addition to maintaining the city’s existing water conservation goals, the WEP recommends the
following focus areas:
Water Use Sector
1994-1996
Baseline Use
% Reduction
Target
Water Use
Target
2012-2015
Baseline
Water Use
Target Met?Units
Single Family 163 22%127 123 yes gallons per resident per day
Multi Family 87 26%64 58 yes gallons per resident per day
Commercial 62 14%53 44 yes gallons per employee per day
Municipal 6.1 1%6 5.7 yes gallons per capita per day
Non-revenue Water 8.5%29.0%6.0%9.0%no % of treated water production
Water Loss, Customer Categorization and City Metering: The city can continue to focus on reducing
citywide water loss through evaluating real-time reading metering options while continuing to improve
system water loss detection and reduction.
Streamline Sustainability and Resilience Initiatives: Continue to identify and address where there can
be both energy and water savings while also continuing to leverage resources to address multi-hazards
(flood and drought), city climate goals, climate modeling and other resilience strategies.
Advance Green Infrastructure Connections: Green Infrastructure or low-impact development planning
can provide multiple co-benefits for departments across the city. The WCP can play a role in maximizing
these co-benefits while focusing on water conservation opportunities and community engagement.
Continue the Adaptive-Resilient Water Conservation Program: The WCP should continue to adapt to
new data and changing conditions and consider if new water conservation goals should be a part of the
2023 WEP update.
The state recently performed a cursory review and had favorable feedback of the draft plan, which
indicates the plan and and its recommendations will satisfy the state’s requirements once the plan is
formally submitted.
CONCLUSION:
The 2016 WEP update goals and recommendations represent a no regrets strategy for future planning.
Based on preliminary feedback, the plan as drafted is expected to satisfy the state’s requirements. In the
near-term, staff will work to implement WEP recommendations and monitor concurrent efforts that can
inform future water conservation goals (e.g. Rate Study; Green Points; Climate Modeling). The city can
evaluate whether or not new water conservation goals are needed in advance of the next WEP update in
2023.
NEXT STEPS:
Attachment A will be used to launch the state-required 60-day public comment period starting October
17, 2016. Should WRAB have any additional feedback during this time period, it will be included, along
with any other public comments staff receives, into the final WEP state submittal to meet the end of year
deadline. The WEP will be made available through www.BoulderSavesWater.net and the Boulder Public
Main Library. We will also be notifying the public about the public comment period through means such
as newspaper advertisements or utility bill inserts.
ATTACHMENTS:
Attachment A – 2016 Water Efficiency Plan
1
Prepared by: Rozaklis & Associates, LLC 520 Concord Avenue Boulder, CO 80304
Prepared for: City of Boulder Boulder, CO
September 2016
2016 Water Efficiency Plan
Attachment A
Attachment A: Water Efficiency Plan
1
Executive Summary
As required by the 2004 Water Conservation Act, the City of Boulder (city) developed a Water
Efficiency Plan (WEP), previously called a Water Conservation Plan in 2009 (2009 WCP).
The purpose of this 2016 WEP plan is to provide updated guidance for implementing the city’s
Water Conservation Program in a way that is compatible with the city’s water supply system,
adopted water conservation goal and programs, water resources management strategy, and
community values. This update also serves to fulfill the statutory requirements to submit a
revised plan to the Colorado Water Conservation Board every seven years.
Today, the city manages a wide range of water conservation measures designed to implement
the city’s Comprehensive Water Conservation Program, which was adopted by City Council as
the city’s water conservation goal. The intent of the Comprehensive Program is to reduce
indoor and outdoor water uses within each customer class and to reduce the city’s treated water
losses. The Comprehensive Program has been expressed in terms of specific water use
reduction targets including:
22 percent reduction in per meter use for the single-family residential sector;
26 percent reduction in per meter use for multifamily residential sector;
14 percent reduction in per meter use for the commercial/industrial sector;
1 percent reduction in overall municipal use, and
real and apparent losses of water no greater than 6% of treated water use.
Long-term attainment of these targets is intended to achieve an approximate 20% reduction in
overall per capita water demand by buildout. Achievement of the city’s water conservation
goal has largely been accomplished to date through an extensive Water Conservation Program
that continues to develop and adapt to changing conditions.
The city provides potable water to approximately 114,400 residents in its service area (2012-
2015 average), which encompasses a total of just under 26 square miles. The city’s existing
total annual treated water use is approximately 18,200 acre-feet (2012-2015 average), primarily
supplied by surface water withdrawn from Boulder Creek, and secondarily from the Colorado-
Big Thompson and Windy Gap Projects on the western slope. Residential single-family users
make up most of the 29,305 active connections (2012-2015 average) to the city’s water supply
system, and represent about 65 percent of total water use. Across all sectors, citywide annual
demand per connection totaled approximately 201,900 gallons averaged over 2012-2015.
The city’s total daily per capita water use has varied from year to year from a low of 136
gallons per capita per day (gpcd) in 2014 to a high of 209 gpcd in 1988. The city’s average per
capita water use from 2012-2015 is 142 gpcd. From 2000 to 2015, per capita water use has
significantly declined. However, future water use projections suggest total water use will
begin to increase in the coming years.
Given the projected increase in water use and recommended actions that should take place
prior to the city’s next WEP update in 2023, this report demonstrates how attaining and
maintaining the city’s existing 2009 WCP goal and associated water use reduction targets
continues to be a reasonable water conservation strategy. The 2016 WEP outlines this
throughout four core chapters, which are summarized as follow.
Attachment A: Water Efficiency Plan
2016 Water Efficiency Plan
September 2016
2
Historical Treated Water Use
Boulder’s average treated water for 2012-2015 was 22 percent less than in 2000, the year of
Boulder’s maximum annual treated water use (see Figure 4-1).1 Boulder’s treated water use has
declined significantly in response to Boulder’s Water Conservation Program, increased public
awareness of the need for efficient water use in reaction to the drought of 2002-2006, and the
city’s imposition of mandatory water use restrictions in 2002, which contributed to an
approximate 20 percent reduction in Boulder’s treated water use during the ensuing year.
Boulder’s water use has not returned to pre-2002 levels and has continued to decline. See
Chapter 4, Historical Treated Water Use, for more detailed information on indoor vs. outdoor
usage, use by sector, peak day use and per capita use.
Future Water Demand Trends
Projections for Boulder’s future water demands are based on trends in the following key areas:
Demographic and Land Use Projections – Boulder’s demographic projections
anticipate increased population and employment growth and increased housing density.
Given Boulder’s balance of housing, employment and land use projections, it is not
anticipated that densification will result in a significant increase in irrigation or overall
per capita water use in Boulder.
Per Capita Water Uses - Boulder’s historical per capita water uses have declined
significantly since 2006-2009. Boulder’s total treated water used has averaged 142
gallons per capita per day (gpcd) over 2012-2015. Residential indoor use has averaged
48 gpcd. Boulder’s current baseline water use is shown in Table 5-2, disaggregated by
customer sector and indoor vs. outdoor use. It should be noted that residential uses are
shown in two ways: separated into SF and MF components and also as combined
residential uses.
Natural Replacement of Fixtures and Appliances - It is expected that indoor per capita
water use will continue to decline as the majority of aging water fixtures in Boulder are
replaced with more efficient models that meet the EPA WaterSense standard per new
state regulations.
Ongoing Water Conservation Savings – In addition to savings from natural
replacement, the city’s ongoing Water Conservation Program water is expected to
reduce per capita indoor and outdoor uses via installation of fixtures that are more
efficient than EPA WaterSense standards, auditing and efficiency improvements to
commercial, industrial and institutional (CII) uses, xeriscaping and urban irrigation
system improvements.
Climate Change Effects on Projected Water Demands - There is now broad recognition
that the future climate will be different than the past and that this will affect the city’s
water demands. This is specifically true of outdoor water use where increased
temperatures are likely to increase unit irrigation demand (which is consistent with
current customer behavior patterns). Although Boulder’s water supply system seems to
be sufficiently robust to meet its reliability criteria, the effects of climate change
1 Normalizing for irrigation water requirement.
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combined with additional changes in Boulder’s population and employment growth are
likely to create upward pressure on Boulder’s future water demands.
Projected Future Water Demands
Boulder’s projected future water demands, reflecting the combined effects of the city’s updated
demographic projections, expected savings from continued natural replacement of fixtures and
appliances, projected additional savings from the city’s active Water Conservation Program,
and the range of expected climate change effects on outdoor water uses are shown below.
The Adaptive-Resilient Water Conservation Program
Boulder’s current water conservation goal and associated water use reduction targets, coupled
with a “no backsliding” principle, are still valid for curbing future water use increases.
Achieving and maintaining the current Water Conservation Program goal will not cause a
further drop in Boulder’s water use but will instead reduce what would otherwise be a greater
increase in projected water use. Uncertainties in future projections requires the Water
Conservation Program to be adaptive. The Water Conservation Program has worked toward
continuing to meet the water conservation goal but also adding value beyond its immediate
mission through enhanced coordination with larger city efforts. Among other things, the Water
Conservation Program supports the city’s resilience goals, instream flow augmentation in
Boulder Creek, agricultural water leasing, climate goals and stormwater quality.
Recommendations
The 2016 WEP study recommends action (see Chapter 8) in the following areas:
1. Have an Adaptive-Resilient Water Conservation Program
2. Streamline Sustainability and Resilience Initiatives
3. Advance Green Infrastructure Connections
4. Evaluate City Metering, Customer Categorization and Water Loss
units 2040 2050 2078(AF)19,191 18,696 19,980(gpcd)126 123 131(AF)17,920 17,267 18,171(gpcd)118 113 119(AF)19,875 19,478 20,997(gpcd)130 128 138(AF)21,716 21,640 23,908(gpcd)142 142 157
Projected demand with conservation, natural replacement & climate change (minimum of modeled results)Projected demand with conservation, natural replacement & climate change (average of modeled results)Projected demand with conservation, natural replacement & climate change (maximum of model results)
Projected Water Demand
Water Demand Projection ScenarioProjected demand with conservation and natural replacement
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Contents
Executive Summary ........................................................................................................1
1 Introduction .........................................................................................................6
1.1 BACKGROUND ....................................................................................................6
1.2 PURPOSE OF THE 2016 WATER EFFICIENCY PLAN ..............................................8
2 Profile of Existing Water Supply System..........................................................8
2.1 WATER SUPPLY RELIABILITY ..........................................................................10
2.2 SUPPLY-SIDE LIMITATIONS AND FUTURE NEEDS .............................................11
3 Water Conservation Program Overview ........................................................11
3.1 HISTORY OF BOULDER’S WATER CONSERVATION PROGRAM ..........................11
3.2 CURRENT WATER CONSERVATION PROGRAM .................................................13
3.3 STATUS OF BOULDER’S CURRENT WATER CONSERVATION GOAL ...................13
3.4 WATER USE AND THE BLOCK RATE STRUCTURE .............................................15
3.5 WATER RATES AND BUDGETS .........................................................................17
3.6 CII WATER BUDGET STUDY ............................................................................17
4 Historical Treated Water Use ..........................................................................18
4.1 DATA SOURCES AND CALCULATION METHODS USED ......................................18
4.2 REPORTING PERIODS ........................................................................................19
4.3 ISSUES WITH CALCULATING SF AND MF PER CAPITA WATER USES ...............20
4.4 COMBINED TOTAL AND PER CAPITA TREATED WATER USE ............................20
4.5 PEAK DAY USE ................................................................................................22
4.6 WATER USE BY CUSTOMER SECTOR ................................................................23
4.7 INDOOR AND OUTDOOR WATER USE ...............................................................24
5 Future Water Demands ....................................................................................28
5.1 BACKGROUND ..................................................................................................28
5.2 SCENARIO PLANNING .......................................................................................29
5.3 DEMOGRAPHIC AND LAND USE PROJECTIONS ..................................................31
5.4 BASELINE PER CAPITA WATER USES ...............................................................32
5.5 NATURAL REPLACEMENT OF FIXTURES AND APPLIANCES ...............................33
5.6 WATER CONSERVATION SAVINGS....................................................................36
5.6.1 SAVINGS ATTRIBUTED TO BOULDER’S WATER CONSERVATION EFFORTS .......36
5.6.2 PROJECTED FUTURE SAVINGS FROM WATER CONSERVATION .........................36
5.7 CLIMATE CHANGE EFFECTS ON PROJECTED WATER DEMANDS .......................37
5.8 PROJECTED WATER DEMANDS .........................................................................40
6 Planning Considerations ..................................................................................41
7 An Adaptive-Resilient Water Conservation Program...................................44
8 Recommendations .............................................................................................48
9 References ..........................................................................................................49
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List of Figures
Figure 4-1: Annual and Per Capita Treated Water Use .................................................22
Figure 4-2: Boulder’s Peak Day Use, 1971-2015 ...........................................................23
Figure 4-3: Average 2012-2015 Water Use by Customer Sector ..................................23
Figure 4-4: Pre-2002 and Current Water Use by Customer Sector ...............................24
Figure 4-5: Indoor Water Use as a Percent of Total Use ...............................................25
Figure 4-6: Annual and Per Capita Indoor Water Use ...................................................26
Figure 4-7: Per Capita Indoor Water Use by Customer Sector .....................................26
Figure 4-8: Annual Outdoor Water Use and Irrigation Water Requirement .................27
Figure 4-9: Per Capita Outdoor Water Use, Irrigation Water Requirement and
Trends ..........................................................................................................28
Figure 5-1: Adaptive Scenario Planning .........................................................................30
Figure 5-2: Range of Projected Average Monthly Temperature with Climate Change for
Boulder ........................................................................................................38
Figure 5-3: Range of Projected Average Monthly Precipitation with Climate Change for
Boulder ........................................................................................................39
Figure 5-4: Range of Projected Average Monthly IWR with Climate Change for
Boulder ........................................................................................................39
Figure 5-5: Projected Water Demands ............................................................................40
List of Tables
Table 1-1: Summary of Water Supply Planning Activities and Projects ..........................7
Table 3-1: List of Boulder’s Existing Water Conservation Program Elements..............13
Table 3-2: Status of Boulder’s Attainment of its Water Conservation Goal ..................14
Table 3-3: Build-out (2080) Water Demands Assuming Boulder’s Previously Adopted
Water Use Targets (updated and corrected) ................................................14
Table 3-4: Water Budgets and Five-Block Rate Structure .............................................15
Table 3-5: Basis for Water Budgets ................................................................................15
Table 3-6: Summary Results of Water Budget Analysis ................................................16
Table 4-1: Boulder’s Largest Water Use Customers ......................................................24
Table 5-1: The City of Boulder’s Demographic Projections ..........................................32
Table 5-2: Baseline Water Use (Normalized 2012-2015 Average) ................................33
Table 5-3: Expected Reductions in Indoor Per Capita Uses from Natural
Replacement ................................................................................................35
Table 5-4: Estimated Savings from Boulder’s Water Conservation Program Since
2009 .............................................................................................................36
Table 5-5: Expected Reductions in Per Capita Uses from Active Water Conservation .37
Table 5-6: Projected Percent Change in April-October IWR for Boulder ......................38
Table 5-7: Boulder’s Projected Future Water Demands .................................................41
Table 7-1: Boulder’s Near-Term Water Use Targets .....................................................45
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1 Introduction
1.1 Background
This 2016 Water Efficiency Plan (2016 WEP) is an update of the City of Boulder’s (the city’s)
2009 Water Conservation Plan (2009 WCP), and was completed to incorporate new information
in key areas that affect the water demands and conservation activities of the Boulder community
(Boulder), and in accordance with Colorado’s statutory requirements for municipal water
providers to review and update their water conservation plans at least once every seven years.
Water conservation has been an important part of the city’s water management for over twenty-
five years. In 1988, Boulder adopted a three-tiered increasing block rate structure to encourage
water conservation during the peak summer demand season. In 1992, Boulder established its
Water Conservation Program to promote efficient water use throughout the year.
In 2000, Boulder’s Water Conservation Futures Study (WCFS) proposed a Comprehensive
Water Conservation Scenario (Comprehensive Scenario), which included a range of educational
and voluntary program elements to reduce indoor and outdoor uses. The Comprehensive
Scenario was adopted as the city’s water conservation goal as part of the city’s 2000 Treated
Water Master Plan and resulted in substantial revisions to and increased funding of Boulder’s
Water Conservation Program. The Comprehensive Scenario identified a range of Water
Conservation Program elements that would result in an approximate 20 percent reduction in total
per capita water use by buildout, compared to projected water use without water conservation.
The 2009 WCP provided guidance for achieving the Comprehensive Scenario and developed
specific per meter and system-wide water use reduction targets for customer sectors, consistent
with the Comprehensive Scenario’s program elements, to be achieved by buildout. The 2009
WCP was approved by the Colorado Water Conservation Board (CWCB). Boulder’s Water
Utilities Master Plan (WUMP), approved in 2011, expressed the 2009 WCP’s water use
reduction targets as customer sector-specific per capita values, supported continuing the existing
2009 WCP measures and sustaining current program funding, but recommended that efforts be
tailored to address current needs. The WUMP’s conservation recommendations have largely
been met via adjustments to conservation efforts, as discussed in Section 3.3.
Boulder’s treated water use has declined significantly in response to the city’s Water
Conservation Program, public response to the need for efficient water use in reaction to the
drought of 2002-2006, and the city’s mandatory water use restrictions in 2002, which contributed
to an approximate 20 percent reduction in Boulder’s treated water use during the ensuing year.
Boulder’s water use has not returned to pre-2002 levels and has continued to decline.
A detailed list of the city’s Water Conservation Program elements and water conservation
planning efforts is provided in Appendix A. Along with its water conservation-related activities,
the city has completed numerous water supply planning efforts and supply development and
facilities projects that have improved its water supply system reliability. These activities and
projects are summarized in Table 1.1. In addition, the city’s ongoing efforts in infrastructure
rehabilitation and maintenance have maintained and improved water supply system reliability.
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Table 1-1: Summary of Water Supply Planning Activities and Projects
Activity/
Project Date(s) Description
Raw Water Master Plan 1988 Provided water supply system overview, developed raw water supply reliability criteria, projected future water demands, assessed existing system adequacy, evaluated alternative water supply plans.
Water Conservation Futures Study (WCFS) 2000 Characterized Boulder’s water uses, updated Boulder’s water demand projections, assessed the reliability of Boulder’s water supply system and recommended a Comprehensive Water Conservation Scenario.
Treated Water Master Plan Update 2000 Updated the city’s capital improvements planning and budgeting to reflect then-current conditions and integrated the 2000 WCFS’s recommended Comprehensive Scenario.
Acquisition of Barker Reservoir System 2001 Increased Boulder’s municipal water supply storage capacity in Middle Boulder Creek by approximately 3,700 acre-feet and provided for more operational control of Barker Reservoir.
Silver Lake and Lakewood Pipeline Reconstruction
1994-2004 Restored Boulder’s raw water delivery rate from its North Boulder Creek sources from 12 mgd to 20 mgd.
Drought Plan (Volume 1 and 2) 2003
Guides Boulder’s drought recognition and responses, which include voluntary efforts for mild/moderate droughts and mandatory measures for severe droughts. Response measures are designed to build on current WCP efforts and allow for further drought response actions.
Boulder Reservoir Water Treatment Plant Improvements 2006 Increased Boulder’s treated water production capacity at the Boulder Reservoir Water Treatment Plant from 12 mgd to 16 mgd.
Climate Change Vulnerability Study 2009
Evaluated the vulnerability of Boulder’s water supply system to climate change. Examined the effects of a range of climate change scenarios on stream flows and water rights. Incorporated paleo-hydrology derived from tree rings and assessed the reliability of Boulder’s water supply system in the context of potential climate variability.
Water Conservation Plan 2009 Developed numeric water use reduction targets based upon the WCFS. Met
the State’s requirements and provided guidance in updating and implementing the city’s WCP.2
Source Water Master Plan Update 2009
Provides a comprehensive framework for managing Boulder’s water supply to meet future needs through drought periods without violating adopted reliability criteria. Incorporated recent projections of future water demands and the results of the drought plan and climate change vulnerability study. Provides guidance on use of excess municipal water supplies to meet non -municipal needs.
Drought Plan Update (Volume 1) 2010 Integrated Boulder’s water budget rate structure into the Drought Plan as a possible drought response measure.
Water Utility Master Plan 2011 Integrated Boulder's water source, storage, treatment, and delivery master plans to facilitate coordinated capital improvement planning.
In December 2012, the city began updating its 2009 WCP to: (1) incorporate the WUMP’s water
conservation-related recommendations; (2) evaluate recent changes to the city’s demographic
projections, water use patterns and Water Conservation Program activities; (3) reflect recent
enhancements to Boulder’s source water supplies and delivery capabilities; and (4) consider new
2 Municipalities with State approved water conservation plans are eligible for financial assistance from the CWCB
and Colorado Water Resources and Power Development Authority.
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information and technologies that could impact Boulder’s water demands, including the effects
of climate change. The results of these efforts are reflected in this 2016 WEP, which also meets
the CWCB’s water conservation planning requirements.
1.2 Purpose of the 2016 Water Efficiency Plan
The main purpose of the 2016 WEP is to assess the status of Boulder’s efforts to meet its water
conservation goal, as embodied in the Comprehensive Scenario and specified by the water use
reduction targets in the 2009 WCP, considering trends in Boulder’s water use patterns, the city’s
most recent demographic projections and the likely range of effects of climate change upon
Boulder’s water demands and supplies. This effort entailed the following:
Review the city’s existing 2009 WCP and evaluate historical water use from 2000 to 2015 in
order to identify significant water use trends and review program effectiveness.
Address factors that could impact Boulder’s future water demands including updated
demographic and land use projections, effects of natural replacement of fixtures and
appliances with more efficient models, the effects of climate change, and the city’s potential
future decisions involving water demand and supply management.
Develop a range of water demand projections that reflect the city’s most recent demographic
projections, trends in water use factors including the likely effects of natural replacement and
the city’s Water Conservation Program, and the likely range of climate change effects.
Address how conserved water could potentially be used for alternate purposes including
enhancing the reliability of Boulder’s water supply system, maintaining or enhancing
instream flows in Boulder Creek and its tributaries, and increasing water leases to local
community-supported agriculture.
Address how water conservation integrates into other aspects of Boulder’s water supply
system and sustainability goals, including the water-energy nexus, water rights
considerations, quality of life and the quantity and quality of urban landscaping.
Incorporate the results from the city’s study of commercial, industrial and institutional (CII)
water uses.
Evaluate whether Boulder has met its water conservation goal in the short term and the
likelihood that Boulder will continue to meet that goal over the long term.
Recommend follow-up activities and studies to enhance the 2009 WCP and assist Boulder in
meeting and refining its water conservation goal.
2 Profile of Existing Water Supply System
Boulder provides water supply, stormwater and wastewater services to a residential population of
approximately 117,000 persons, a wide variety of CII customers and municipal government uses.
The city’s service area includes approximately 26 square miles of lands within Boulder’s
incorporated boundaries or within Planning Area II as designated by the Boulder Valley
Comprehensive Plan (BVCP). Boulder’s service area population has grown by approximately 8
percent in the past ten years and it is anticipated that it will continue to grow by another 16
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percent until Boulder’s residential zoning capacity is projected to be reached in 2040. There are
currently about 101,400 jobs within the service area, and future employment is projected to
ultimately grow by an additional 54 percent until Boulder’s non-residential zoning capacity is
projected to be reached by 2080.
Boulder’s water supplies include direct flow, storage and exchange water rights in the Boulder
Creek watershed and interests in Colorado-Big Thompson (CBT) and Windy Gap water projects.
Boulder’s direct flow rights include originally decreed municipal rights associated with the Town
of Boulder Ditch, the Boulder City Pipeline and the Boulder City Pipeline No. 3; and changed
irrigation rights of the Anderson, Farmers, Harden, McCarty, Smith & Goss, North Boulder
Farmers, and Lower Boulder ditches; which are diverted from North Boulder Creek via the
Boulder City Pipeline, from Middle Boulder Creek via the City of Boulder Pipeline No. 3, and
from Boulder Creek via the Farmers Ditch.
Boulder’s storage rights are associated with Silver Lake, Island Lake, Goose Lake, Albion
Reservoir and the Green Lakes in the North Boulder Creek watershed; with Barker Reservoir and
Skyscraper Reservoir in the Middle Boulder Creek watershed; and with Baseline Reservoir and
Wittemyer Ponds. The combined storage capacity associated with Boulder’s storage rights is
approximately 20,000 acre-feet. Boulder’s trans-basin supplies include 21,015 CBT units and 37
Windy Gap units. Boulder’s exchange rights allow Boulder to exchange its CBT supplies,
Windy Gap supplies, Baseline Reservoir storage rights, some of its changed irrigation rights and
some of its municipal return flows upstream for direct use or storage and subsequent use at its
Middle Boulder Creek and North Boulder Creek points of diversion.
Water is treated at the city’s Betasso and Boulder Reservoir water treatment plants (WTPs) and
conveyed to customers through over 400 miles of water distribution pipelines. Wastewater is
collected and treated at the 75th Street wastewater treatment facility. A full description of
Boulder’s water supply system is provided in Boulder’s Source Water Master Plan3.
Boulder leases some of its temporarily unused raw supplies to various agricultural users in the
Boulder Creek and Left Hand Creek basins on a year-to-year basis. A relatively small number of
properties within Boulder’s service area, including a few parks and school grounds, the main
University of Colorado campus, the NOAA/NIST campus and several private lots own shares in
irrigation ditch companies and use non-potable irrigation water provided by those ditches.
Boulder’s ability to implement water reuse is limited because most of Boulder’s water rights are
not reusable. A relatively small portion of Boulder’s water supplies is fully consumable and
could be reused. Boulder uses return flows from those supplies to meet its augmentation and
return flow replacement requirements, and as an exchange supply.
Boulder’s water supply system is not in a designated critical water supply area. Boulder is
located in the Boulder County portion of the South Platte Northern Counties as defined by the
Statewide Water Supply Initiative (SWSI) 2010 report. According the SWSI 2010 report,
Boulder County appears to have no 2050 supply gaps.
Boulder has considered and adopted ordinances, regulations and policies that are designed to
encourage efficient water use and to respond effectively to droughts. These include mandatory
metering, Boulder’s water supply reliability criteria, support of the city’s ongoing Water
3 City of Boulder. April 2009.
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Conservation Program, Boulder’s water budgets and associated water rate structure, Boulder’s
Drought Plan and the City Manager’s authority to declare a drought and to restrict water uses,
and Boulder’s Green Points and SmartRegs programs, which “build-in” efficient water use into
new construction, redevelopment and some existing development. The water savings associated
with these ordinances, regulations and policies, while significant, cannot be readily separated
from savings resulting from other factors including the city’s Water Conservation Program.
2.1 Water Supply Reliability
During the development of its 1988 Raw Water Master Plan4, Boulder adopted water supply
reliability criteria, which set performance standards for raw water supply reliability that struck a
balance between the costs and environmental impacts of increased reliability and the
consequences of temporary water supply restrictions. Those criteria are described below.
For water uses deemed essential to the maintenance of basic public health, safety and welfare
such as indoor domestic, commercial and industrial uses and firefighting uses, Boulder shall
make every effort to ensure reliability of supply against droughts with recurrence intervals of
up to 1,000 years.
For that increment of water use needed to provide continued viability of outdoor lawns and
gardens, Boulder shall make every effort to ensure reliability of supply against droughts with
recurrence intervals of up to 100 years. (The phrase ‘continued viability of outdoor lawns and
gardens’ has been defined as provision, at a minimum, of the amount of water necessary to
meet the basic survival needs of outdoor landscaping in general, including trees and shrubs.)
For that increment of water needed to fully satisfy all municipal water needs, Boulder shall
make every effort to ensure reliability of supply against droughts with recurrence intervals of
up to 20 years.
Boulder has utilized the reliability criteria to formally assess the adequacy of its water supply
system and to make water supply planning decisions. In its 2003 Drought Plan, Boulder
developed drought response triggers and related demand reduction strategies for four different
drought stages. Boulder analyzed the reliability of its water supply system, at projected buildout
water demands and assuming attainment of Boulder’s water conservation goal, against 300 years
of paleo-hydrology reconstructed from tree ring data. That analysis showed that Boulder’s water
supply system would be capable of meeting its projected buildout demands (then projected to
occur by 2020), plus a 10 percent safety factor, in a manner consistent with Boulder’s adopted
reliability criteria over the 300-year modeled period.
During 2006-2008 the city participated in a study of the vulnerability of Boulder’s water supply
system to the potential effects of climate change combined with long-term hydrologic variability
(as evidenced by 437 years of paleo-hydrology)5. That study showed that Boulder’s water
supply system appears to be sufficiently robust to meet its two most important reliability criteria
– supplying water uses deemed essential to basic public health, safety and welfare, and ensuring
continued viability of outdoor lawns and gardens - in most of the future possible climate
conditions modeled.
4 WBLA, Inc., 1988.
5 Smith et. al., 2009.
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Both of the aforementioned reliability assessments assumed that Boulder’s projected buildout
water demand would be significantly greater than what is currently projected. Also, while the
Climate Change Vulnerability Study used the best available climate change and hydrology
modeling at that time, newer and significantly improved climate modeling and hydrology data
are available. As described in Section 0, the city is updating its reliability assessment to reflect
attainment of its water conservation goal, its most recent demographic projections, the latest
available climate change information and the resulting updated water demand projections.
There are other factors, which were not explicitly addressed in the above-described reliability
assessments, that could significantly affect the city’s ability to provide municipal water supplies,
including a potential Colorado River compact call, wildland fire, infrastructure failure or a major
contamination event.
2.2 Supply-Side Limitations and Future Needs
Based on Boulder’s previous water supply reliability assessment that considered climate change,
Boulder has sufficient supplies to meet its projected future needs at the standards of its reliability
criteria under a majority of future climate scenarios. This finding will be reviewed and updated
as part of Boulder’s updated reliability assessment, which is scheduled for completion later this
year. The updated assessment will incorporate the results of the Fifth Assessment report from
the Intergovernmental Panel on Climate Change, as well as the most recent downscaled climate
modeling data developed by the State of Colorado in its Colorado Water Availability Study. The
updated assessment will also incorporate Boulder’s most recent projected buildout water
demand, as presented below.
3 Water Conservation Program Overview
3.1 History of Boulder’s Water Conservation Program
Boulder’s initial water conservation efforts included a shift from a flat rate to a quantity charge
for water used by metered customers, and required water meters for all new residential
construction in 1952. The universal metering program was completed by 1964. The
combination of universal metering and a quantity charge resulted in a 33% short-term decline in
Boulder’s overall per capita water use from a 1956-1962 average of 226 gpcd to a 1964-1970
average of 152 gpcd. Overall per capita use gradually increased to an average of 188 gpcd by
the 1980s and 1990s but never returned to pre-1964 levels6.
Faced with increasing peak-day water demands and limited water treatment capacity, in 1988
Boulder moved from a quantity charge to a three-tiered increasing block rate structure to
encourage water conservation during the peak summer demand season. Boulder’s 1990 Treated
Water Master Plan (TWMP) recommended water conservation as the most cost effective means
of increasing system flexibility. In 1990, Boulder’s City Council approved implementation of an
6 WBLA, Inc., 1988
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enhanced Water Conservation Program with the primary purpose of deferring the expansion of
the Boulder Reservoir WTP.
The Water Conservation Program was formally established in May 1992 to direct the efforts of
reducing overall water consumption within the city and to reduce summer peak demand use. The
Water Conservation Program was adopted by City Council as a single staff (one full-time
equivalent) program and is currently managed under the Utilities Division (Utilities) under the
Public Works Department in the Water Quality and Environmental Services (WQES) Group.
In 2000, Boulder completed its Water Conservation Futures Study (WCFS), which characterized
Boulder’s treated water uses, formulated and evaluated several water conservation scenarios, and
projected Boulder’s treated water demands under each of those scenarios from a 1994-1996
baseline condition through buildout, which was then assumed to occur by 2020. Boulder
selected as its water conservation goal the WCFS’s Comprehensive Conservation Scenario
(Comprehensive Scenario), which included a range of program measures aimed at reducing both
indoor and outdoor water uses within each customer sector, as well as reducing system treated
water losses. The Conservation Scenario’s program measures were specified in terms of
adoption rates and expected savings for indoor and outdoor use for each customer sector. The
Comprehensive Scenario did not include a specific goal for Boulder’s total treated water use,
although the WCFS did project that, given the city’s demographic projections at that time,
attainment of the Conservation Scenario’s program measures would reduce Boulder’s projected
buildout water demand by 22 percent compared to projected buildout demand with no additional
water conservation (i.e. no change in 1994-1996 baseline per capita water use factors). The
Comprehensive Scenario was adopted by City Council as part of the 2000 TWMP and required
substantial revisions to the city’s existing Water Conservation Program and an increase in
funding to support adopted water conservation initiatives.
Following the city’s imposition of water use restrictions in response to severe drought conditions
in 2002, the city began examining the use of customer-specific water budgets as an alternate
method for reducing water demand in response to drought while providing more flexibility in
individual customer responses, and as a way to encourage savings in water use in a manner
tailored to individual customer’s circumstances. This process led to Boulder’s adoption of a
water budget-based rate system including a five-tiered rate structure, described in more detail in
Section 3.4.
In 2009, the city submitted the 2009 WCP to the CWCB, to comply with state law requiring
submittals of Water Conservation Plans (now Water Efficiency Plans). The 2009 WCP provided
guidance for implementing the Comprehensive Scenario, and developed customer sector-specific
water use reduction targets, expressed as percent reductions in per meter water use and percent
reductions in real and apparent water losses, compared to WCFS baseline uses, by buildout.
Boulder’s WUMP was approved in 2011 and supported continuing the city’s 2009 WCP
measures and sustaining current program funding but suggested that efforts be tailored to address
current needs. Relevant WUMP recommendations (Volume 2) include:
Evaluating CII water budgets
Coordinating with Boulder’s Climate and Sustainability Division
Targeting high volume water use customers
Reviewing and revamping the water conservation rebate program
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The WUMP’s conservation-related recommendations have been addressed via various
conservation efforts, as discussed in Section 3.3. Appendix B lists the key water conservation
activities implemented since the 1992 Water Conservation Program began. These programs
were designed to lower peak-day demands, delay certain capital improvement projects, reduce
total water use at buildout and meet the water conservation future goal and associated water use
reduction targets discussed above.
3.2 Current Water Conservation Program
Significant changes have been made to the Water Conservation Program since its inception in
1992. The current program focuses on all water customer sectors including single family (SF),
multifamily (MF), CII, municipal and metered irrigation. Some of the activities are implemented
solely by the city while others are in collaboration with other entities (see Section 7.1.5). Many
of these changes have been implemented based on WUMP findings and evaluation of recent
water use and trends as described in the following section. Boulder’s existing Water
Conservation Program elements are listed in Table 3-1. Details are provided in Appendices A
and B.
Table 3-1: List of Boulder’s Existing Water Conservation Program Elements Water Conservation Office Slow the Flow Audits Water Budget Rate Structure Xeriscape Demonstration Plots CII Audits M36 Water Audits & Loss Control Program Xeriscape Seminars Contracted Commercial & Residential Programs Campaigns Customer Education & Outreach Free Ultra-Low Flow Toilet with Install Operation Water Festival Garden-in-a-Box Program Turf Demonstration Plots Water Efficiency Fund Leak Notices
3.3 Status of Boulder’s Current Water Conservation Goal
The city’s WUMP confirmed that most of the water use targets of the city’s water conservation
goal had been met based upon water use and demographic data available at that time. An
updated analysis, summarized in Table 3-2, reaches that same conclusion based upon 2012-2015
data. Only the target of reducing non-revenue water to less than 6 percent of treated water
production remains unmet. Specific details of this updated analysis are provided in Appendix C.
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Table 3-2: Status of Boulder’s Attainment of its Water Conservation Goal
Applying the corrected and updated water use targets shown above to the city’s current
demographic projections, which are described in Section 5.3, results in a projected buildout year
(2080) water demand of 24,973 acre-feet per year, as shown in Table 3-3.
Table 3-3: Build-out (2080) Water Demands Assuming Boulder’s Previously Adopted
Water Use Targets (updated and corrected)
The city’s continued efforts under its Water Conservation Program, combined with the ongoing
effects of natural replacement of existing water-using fixtures and appliances with more efficient
models, are likely to further reduce current per capita water use factors over the short term.
However, Boulder’s future water use may rise over the longer term given the potential effects of
climate change. Expected warmer temperatures are likely to increase outdoor water demands,
which may increase per capita uses in each customer sector. Similarly, if future employment
grows to reach the city’s current zoning capacity, the city’s total per capita use may rise due to
the proportionately greater amounts of CII water use. These issues are discussed in Sections 5.3
and 5.6. Boulder’s existing conservation goal and continued water conservation efforts are
commensurate with a “no-low regrets” strategy as the city continues to move forward on related
planning efforts, which can be reevaluated in the next WEP update in 2023. “no-low regrets” are
further described in Section 5.2.1.
Water Use Sector
1994-1996
baseline use
(corrected
and
updated)1
Water use
percent
reduction
target
Water use
target
(corrected
and
updated)2
2012-
2015
baseline
use3
Water use
target met?Units
Single Family 163 22%127 123 yes gallons per resident per day
Multi Family 87 26%64 58 yes gallons per resident per day
Commercial/Industrial 62 14%53 44 yes gallons per employee per day
Municipal 6.1 1%6.0 5.7 yes gallons per capita per day
Non-revenue water4 8.5%29%6.0%9.0%no % of treated water production
4. Total annual treated water production minus total annual metered water use.
1. Derived from average 1994-1996 water uses, corrected customer sector-specific population calculations, and updated estimates
of 1994-1996 service area population and employment. The outdoor portions of water uses were normalized to represent demand
under average weather conditions.
3. Derived from average 2012-2015 water uses, service area population and employment. The outdoor portions of water uses were
normalized to represent demand under average weather conditions.
2. Derived by applying the sector-specific and system-wide water use reduction goals from the 2009 WCP to the corrected and
updated 1994-1996 baseline use.
Water Use Sector
Water use
target Units
Projected Water
Demand, AF
Single Family 127 gallons per resident per day 49,767 SF residents 7,080
Multi Family 64 gallons per resident per day 86,333 MF residents 6,189
Comm./Ind./ Inst.53 gallons per employee per day 156,500 employees 9,291
Municipal 6.0 gallons per capita per day 136,100 residents 915
Non-revenue water3 6.0%% of treated water production 1,498
Total Treated Water Demand 147 gallons per capita per day 136,100 residents 24,973
Demographic Projection
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3.4 Water Use and the Block Rate Structure
Boulder had a uniform quantity charge water rate structure until 1988 when it first implemented
a three-tiered increasing block rate structure.7 In December 2004, Boulder adopted a new rate
structure that combined an inclining five-tiered block rate structure with customer-specific water
budgets. This new system was not implemented until 2007, in part due to the need to purchase a
new utility billing system that could accommodate water budgets. The five-tiered block rate
structure is based on Utility-established monthly water budgets, which include indoor and
outdoor allocations. As shown in Table 3-4, customers using 60 percent of their water budget or
less are in Block 1 and are charged ¾ of the base rate. Customers within 61 percent to 100
percent of their water budget are charged the base rate while customers exceeding their water
budget are in either Blocks 3, 4 or 5 and are required to pay increasing rates based upon the
degree to which they are over budget. Table 3-5 summarizes how the water budget for each
customer sector is calculated.
Table 3-4: Water Budgets and Five-Block Rate Structure
Rate Block
% of Water
Budget
Block Rate
(per 1,000 gallons) Block 1 0-60% $2.76 (¾ base rate) Block 2 61%-100% $3.68 (base rate) Block 3 101%-150% $7.36 (2 x base rate) Block 4 151%-200% $11.04 (3 x base rate) Block 5 over 200% $18.40 (5 x base rate)
Table 3-5: Basis for Water Budgets
Accounts Monthly Water Budget Calculation
Single Family Indoor allotment (7,000 gallons/month, which assumes a 4-person household) + outdoor allotment (based on customer-specific irrigable area and seasonal watering needs).
Multi- Family
Indoor allotment (4,000 gallons/month/dwelling unit with 1-2 bedrooms) + outdoor allotment (based on customer-specific irrigable area and seasonal watering needs). A dwelling unit with more than two bedrooms may receive an additional 1,000 gallons/month, up to a maximum indoor allocation of 7,000 gallons/month.
Irrigation Only Outdoor allotment is 15 gallons per square foot (based on customer-specific irrigable area and seasonal water needs).
CII and Municipal
CII customers may choose from the following options:
Average Monthly Use (AMU) – (Default option). The AMU budget is calculated using the monthly average of 12 consecutive months of water use for an account, so that each month's water budget is the same. Customers can apply to change the time frame used for the 12-month average. (The default time frame is January through December 2005).
Historical Monthly Use (HMU) - The HMU budget is calculated using a rolling three-month average for each individual month. For example, the average of the past three January's use would be next year's January budget.
7 The three-tier structure used Average Winter Consumption (AWC), defined as the average December-March
monthly use by each account, as the basis for the Block 1 allowance. Block 2 was set at 350 percent of Block 1 usage,
which allowed for reasonable outdoor use, with any usage above this amount charged at the highest rate in Block 3.
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Accounts Monthly Water Budget Calculation
CII and Municipal Indoor/Outdoor - The Indoor/Outdoor budget is comprised of both an indoor water allocation and an outdoor water allocation. The indoor allocation may be based on either the most recent Average Winter Consumption (AWC), AMU or HMU. The outdoor allocation is calculated based on irrigable area, including right of way, and seasonal watering needs.
Efficiency-Standard - This option allows for a specific customized water budget. The customer must hire a professional engineer to evaluate and recommend a personalized indoor budget, which then must be reviewed and approved by the city. The customer will be charged a fee for the city review.
PIF –This option is for new customers or customers who are significantly changing their use and a larger meter is needed. Customers can buy 25%, 50% or 85% of their water
meter based on the customer’s class average for that meter size.
Notes:
1. Most outdoor budgets provide an irrigation allowance of 15 gallons per square foot, which is equivalent to
approximately 85 percent of the average irrigation water requirement (IWR) for Kentucky bluegrass assuming 80
percent irrigation efficiency. This is a reasonable allowance because the unit IWR for Kentucky bluegrass is greater
than that for other types of landscaping, and because lots are rarely planted with 100 percent bluegrass. SF
properties with more than 5,000 square feet of irrigable area have irrigation allowances of less than 15 gallons per
square foot.
2. For outdoor use, such as the irrigation of parks, some allowance may be made for increased water use to offset
damage done by higher foot traffic.
An analysis was conducted to identify the percent of accounts that exceeded 100 percent of their
water budget during 2007-2011. The number of accounts that terminated in each block was
initially summed on an annual basis to identify whether there were certain years in which a larger
number of accounts exceeded their water budget. The results indicated that, while there was a
typical percentage range of accounts that exceeded their water budget every year, there was not a
particular pattern or trend in the data.
The number of accounts that terminated in each block was then averaged on a monthly basis by
customer sector. The results of this are summarized in Table 3-6. Graphs providing more
detailed results are included in Appendix G.
Table 3-6: Summary Results of Water Budget Analysis
The greatest frequencies of water budget exceedances occur during the irrigation months of May
to October, although a significant number of budget exceedances also occur during the non-
irrigation months. The SF sector has the lowest percentage of exceedances in all months of the
year. However, it should be noted that SF customers receive an indoor allotment of 7,000
gallons per month, which is relatively generous for households with less than four persons. SF
customers who do not fully use their indoor water budget can therefore use the excess portion of
their indoor budget for outdoor irrigation without exceeding their combined indoor/outdoor
water budget. As noted above, the 15 gallon per square foot irrigation allowance is sufficient to
Block 1 Block 2 Block 3 Block 4 Block 570.6% 21.0% 6.7% 1.3% 0.5%58.3% 28.7% 9.2% 2.6% 1.2%53.3% 24.8% 13.2% 5.4% 3.4%65.3% 17.8% 9.5% 4.2% 3.2%
Commercial/Industrial/InstitutionalMunicipal
Customer Sector
Percent of Accounts Staying Within
(in-budget)(out-of-budget)
Single FamilyMultifamily
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supply approximately 85 percent of the average irrigation requirement for Kentucky Bluegrass.
Customers who do not fully use their indoor budget for indoor uses could be irrigating at higher
rates without exceeding their budget.8
Over 10 percent of CII and MF customers exceed their water budgets during the winter. The
number of exceedances for the MF sector tends to be a little lower in February and March when
compared to the trends in the other customer sectors. Additional studies entailing the sub-
metering of individual units and tracking of fluctuations in occupancy levels due to seasonal
student populations may be useful to identify why this may be occurring.
The CII sector has the largest percentage of exceedances in all months. This suggests that
adjustments to the water budgets in the CII sector could be made to more appropriately reflect
the use of individual customers. The city has evaluated whether benchmark-based billing could
be a possible tool for better addressing CII water budgets but the results have shown that
applying that methodology to billing is problematic, raises equity questions and may not result in
water savings. Additional evaluation of CII water budgets and all customer classes is currently
being accessed through the city’s 2016 Utility Rate Study.
3.5 Water Rates and Budgets
Effective water rates are a key tool for managing demand as well as for generating sufficient
revenue for operations, maintenance and capital improvement projects. The city conducts a
water rate study every five to seven years to ensure that their water rates are sufficiently meeting
these objectives. The city is currently conducting the next rate study, which will conclude in
2016. Numerous studies have shown that customer water use tends to decrease in response to an
increased water rate price signal9. The ratio of percent change in water demand to percent
change in price has been termed demand elasticity with respect to price. However, there are
other drivers of customers’ water use and the effectiveness of water budgets will be explored in
the 2016 Utility Rate Study. While the downward trends in Boulder’s historical per capita water
uses appear to be generally correlated with changes in Boulder’s water rate structures and
increases in Boulder’s water prices, no studies have specifically identified a price response in
Boulder’s case.
3.6 CII Water Budget Study
Under direction from City Council and the city’s Water Resources Advisory Board (WRAB),
Utility staff initiated a CII water use study in 2009 to explore alternate methods for setting
efficiency-based water budgets for the CII customer sector in lieu of the existing method, which
relies on historic use. The study explored options ranging from a no action alternative to equal
reduction in water budgets across all sectors to establishing a benchmark approach. The WRAB
recommended further analysis of benchmark-based water budgets as a possibly effective way to
establish fair and equitable CII water budgets.
8 Note: Single family indoor water use has generally declined since 2007 while the indoor water budget has remained
at 7 kgal.
9 Gibbons, 1986
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Additional analysis recognized the high degree of variability in CII water uses and the need to
allow for individual adjustments. In 2011, WRAB recommended that the city move forward
with exploring a “combined approach” that relied on both benchmarks and water audits to
establish CII water budgets. Benchmarks were developed in 2012 (using 2011 data) through a
statistical approach to establish individual sub-sector categories within the CII sector (i.e.
restaurants, hospitals, etc.). The methodology staff identified was presented to WRAB in 2013.
In exploring the efficacy of this approach, staff determined that using benchmarks to bill
customers would neither address water conservation nor equity concerns – the main issues of
concern. Findings from the CII benchmarking study were presented to WRAB in 2015 and study
results will be used to inform the city’s larger 2016 Utility Rate Study.
4 Historical Treated Water Use
4.1 Data Sources and Calculation Methods Used
Several data sources and calculation methods were used to characterize Boulder’s historical
treated water uses as described below.
1. Boulder’s WTP production records were used to quantify total water use, indoor use and
outdoor use, combined for all customer sectors. Indoor and outdoor uses are differentiated as
follows. For December-February, indoor use is assumed to be 100 percent of daily
production; for March-November, indoor use is assumed to be the minimum of each day's
production and the average daily production for December 1 - December 15 and January 16 -
February 28 for that calendar year. This averaging method avoids periods of unusually low
water use caused by holiday departures of University of Colorado students and other Boulder
residents. Outdoor use was calculated and the difference between total daily use and
calculated daily indoor use. Combined total, indoor and outdoor uses include metered uses
and non-revenue water, which represents both real losses (distribution system leaks) and
apparent losses (metering and reporting error and unmetered uses).
2. Monthly Utility billing records were used to quantify customer sector-specific total use,
indoor use and outdoor use for the major customer categories in Boulder’s billing system:
SF; MF; CII; and municipal (use by city departments). For each customer sector, all metered
uses for December-February were assumed to be indoor use. Metered uses for March-
November were split into indoor and outdoor portions by assuming that indoor use is the
minimum of each month’s metered use and the average monthly metered use for December-
February for that calendar year. The billing system also includes irrigation-only accounts,
each of which represents separately metered irrigation use by an associated SF, MF, CII or
municipal account. Irrigation-only accounts were categorized as outdoor water used by their
associated customer sector. Irrigation-only accounts lacking sufficient information to
identify their associated customer sector were not included in the analysis. The number of
such accounts was low enough to not significantly affect the amount or proportion of water
use by customer sector.
3. Estimates of historical service area population, housing and employment provided by the
city’s Planning and Development Services (Planning) were used to calculate per capita uses
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for combined and customer sector-specific total water use, indoor use and outdoor use.
Combined per capita uses were calculated by dividing the type of water use in question (total,
indoor or outdoor) by the total service area population. Customer sector-specific per capita
uses were calculated by dividing the type of water use in question by the estimated
population for the customer sector. In the case of CII water use, service area employment
was used. In the case of municipal water use (i.e. water use by city departments), total service
area population was used. Combined per capita uses are not directly comparable to per
capita uses for individual customer sectors because combined per capita uses are based upon
treated water production records and include non-revenue water whereas per capita uses for
individual customer sectors are based upon metered deliveries and exclude non-revenue
water.
4. Historical monthly temperature and precipitation data from the Boulder NOAA weather
station were used to calculate the annual irrigation water requirement (IWR) for the Boulder
service area. IWR is the amount of water needed to supply the net evapotranspiration (ET)
of a given type of plant, after considering precipitation. IWR is greater in years with
relatively warm and dry irrigation seasons, and less in relatively cool and wet years. Annual
IWR, expressed as a percent of 1950-2015 average, is used to evaluate trends in Boulder’s
outdoor use and to normalize Boulder’s outdoor water use with respect to IWR10. IWR is
estimated for Kentucky Bluegrass, a representative urban turf grass11.
4.2 Reporting Periods
Boulder’s historical water use is characterized for several reporting periods:
Historical uses for 1971-2015 are shown to illustrate long term trends in Boulder’s water
use, which are useful in understanding the historical effects of Boulder’s growth and
development, Boulder’s historical water conservation efforts and the 2002-2006 drought.
Historical uses for 2003-2015 are shown to illustrate trends in Boulder’s water use
following the severe drought year of 2002, when the city imposed mandatory water use
restrictions.
Historical uses for 2012-2015, adjusted to normalize outdoor uses, are reported as
Boulder’s current water use baseline. These years were chosen because they represent the
four most recent years of record. They therefore best reflect the cumulative effects of
Boulder’s Water Conservation Program to date, including its water budget rate structure.
10 Outdoor use is normalized with respect to IWR by dividing the annual volume of outdoor use in a given year by the
percent-of-average IWR for that year. For example, the city’s outdoor use was 8,532 acre -feet in 2012, which was a
relatively warm and dry year: the IWR for 2012 was 118% of average. Dividing 8.532 acre -feet by 1.18 results in a
normalized 2012 outdoor use of 7,253 acre -feet, which is less than the actual 2012 outdoor use but can be compared
to normalized outdoor uses for other years in a valid manner.
11 Kentucky Bluegrass IWR is calculated using the modified Blaney-Criddle method and calibrated monthly crop
growth stage coefficients published by Pochop et al (1984), adjusted to account for elevation. Effective precipitation,
assumed to be 70% of monthly precipitation, is subtracted from ET to obtain IWR.
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4.3 Issues with Calculating SF and MF Per Capita Water Uses
While total residential water use (combined SF and MF) is accurate, the SF and MF per capita
water uses presented in this report should not be considered accurate in an absolute sense. This
is because sector classification methodologies (e.g. SF vs. MF) are not the same between
Planning and Utility Billing.
SF per capita use is calculated by dividing total SF metered water use (provided by Utility
Billing) by the estimated SF population (provided by Planning). Similarly, MF per capita use is
calculated by dividing total MF metered water use (provided by Utility Billing) by the estimated
MF population (provided by Planning). However, it appears that Utility Billing does not
categorize SF and MF customers the same way that Planning categorizes SF and MF dwelling
units and associated population. For example, a strip of connected row homes may be labeled as
MF by Planning but, because they have individual meters, they may be counted as SF by Utility
Billing. The end result of these discrepancies is an overestimation of SF gpcd and an
underestimation of MF gpcd. This disparity has apparently existed since the 1990s, and its effect
can be demonstrated with information from the 2000 WCFS.
Using the 1994-1996 average annual volume of SF indoor water use (as reported by Utilities)
and the estimated 1994-1996 average SF population (as reported by Planning), the average SF
per capita indoor use is calculated as 83 gallons per capita per day (gpcd). This result is
significantly greater than the result from direct measurement of SF indoor water use. The water
uses of a representative sample of 100 single family Boulder homes were measured in 1996 as
part of Boulder’s participation in the AWWARF Residential End Uses of Water Study. The
results of these measurements showed an average SF per capita indoor use of only 66 gpcd, a 26
percent disparity.
According to Planning data, SF dwelling units have consistently comprised between 43 percent
and 45 percent of the total number of dwelling units in Boulder’s service area since 1990.
However, a review of the Boulder County Assessor’s 2014 database suggests that SF dwellings
may comprise at least 50 percent of the total dwelling units in Boulder’s service area.
In spite of these issues, the calculated SF and MF per capita uses are useful for observing relative
trends in uses. The question of whether Boulder has met its existing SF and MF water use
reduction targets can still be meaningfully addressed using the SF and MF per capita uses as
calculated, because the same assumptions and methods used to categorize SF and MF metered
use and to estimate SF and MF population in 1994-1996 continue to be used to date.
However, the absolute accuracy of the SF and MF per capita uses, particularly the accuracy of
MF per capita use, is a concern in projecting Boulder’s future water demands. As currently
calculated, Boulder’s historical per capita MF use is significantly lower than SF use. Because
most of Boulder’s future residential population growth is projected to occur in the MF sector, if
the MF per capita use factor used to project water demands is erroneously low, Boulder’s
projected future water demand may be underestimated.
4.4 Combined Total and Per Capita Treated Water Use
Figure 4-1 depicts Boulder’s combined annual treated water use on a total and per capita basis
for 1971 to 2015. From 1971 through 1988, Boulder’s population grew at a rate of 1.6 percent
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per year and Boulder had only basic water conservation measures in place: universal metering
and a uniform quantity charge. Boulder’s treated water use increased significantly during this
period on both a total and per capita basis. Growth in per capita use during this period was
primarily caused by proportionately greater non-residential growth compared to residential
growth, as Boulder was becoming a regional employment center.
From 1988 through 2001, Boulder’s population growth rate slowed to 0.7 percent per year, and
Boulder implemented a three-tiered increasing block rate structure in 1988. While total treated
water use held relatively steady during this period, Boulder’s per capita water use declined
slightly. While there are no studies that demonstrate an explicit causal relationship, it is
reasonable to assume that part of this decline in per capita water use is in response to Boulder’s
increasing block rate structure and Water Conservation Program.
From 2002 through 2015, Boulder’s treated water use declined significantly on both a total and
per capita basis in response to the drought of 2002-2006, Boulder’s 2002 water restrictions,
Boulder’s Water Conservation Program and Front Range-wide drought awareness efforts, all of
which resulted in reduced customer water use through modified behavior, landscape and
irrigation changes and the installation of more water and energy efficient appliances, fixtures and
devices. Technological advances in the latter have continued to make more efficient models that
exceed industry standards, perform better and has increased market penetration. As discussed in
Sections 4.6 and 4.7, significant declines have occurred across all customer sectors and in both
indoor and outdoor uses.
The drought period of 2002-2006 and related local and Front Range-wide drought campaign
efforts had a significant impact on Boulder’s water customers. Customers reduced their water
use by modifying their behaviors and by installing more water efficient devices. Boulder’s Parks
and Recreation Department also adopted more efficient irrigation practices. The drought also
spurred the city to begin work on a series of water efficiency-based changes including finalizing
a Drought Plan, developing a five-tier block rate structure and initiating water budgets. As a
result, treated water use has fallen from a pre-drought (pre 2002) high of 24,433 acre-feet in
2000 to an average of 18,156 acre-feet for 2012 through 2015.
Boulder’s lowest annual treated water use in the last thirty years (17,280 acre-feet) occurred in
2009. Since then, Boulder’s annual treated water use has increased by an average of 0.4 percent
per year in response to population and employment growth.
It is important to distinguish between pre- and post-2002, as Boulder’s 2002 water use
restrictions, continuing drought conditions through 2006, and customer responses have resulted
in enduring change in Boulder’s water use patterns. Boulder’s treated water use has remained
below 2002 levels. Normalizing for irrigation water requirement, Boulder’s average treated
water for 2012-2015 was 22 percent less than in 2000, the year of Boulder’s maximum annual
treated water use (see Figure 4-1).
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Figure 4-1: Annual and Per Capita Treated Water Use
As discussed in more detail in Section 4.7, much of the annual variation in Boulder’s treated
water use is due to annual variations in irrigation water requirement (IWR), caused by variable
weather conditions, and its effects on outdoor use. While annual outdoor use continues to vary
from year to year, Boulder’s overall level of outdoor use declined significantly after 2002,
although there has been a slight upward trend in outdoor use since 2002.
4.5 Peak Day Use
Peak day use is defined as the maximum combined daily volume of treated water produced at the
city’s two WTPs during the year. Boulder’s historical peak day use is shown in Figure 4-2.
Boulder’s peak day use generall y increased until 1989, the year following Boulder’s
implementation of an increasing block rate structure. Boulder’s highest single day peak use was
50.5 MGD, which occurred on July 7, 1989. Peak use generally declined from 1989 until 2002,
when the city imposed mandatory water use restrictions in response to the extreme drought
conditions in 2002. Since 2002, Boulder’s peak use has fluctuated between 31 MGD and 39
MGD with no apparent longer-term trend. By comparison, Boulder’s treated water production
capacity is approximately 61 MGD. Therefore, peak demand management is not currently a
priority for Boulder’s water conservation efforts.
167
162
175
190
178
174
169
181 184
197
170 169
187
182
191
194
192
209
202
185
178
195
180
198
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187 188
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154
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153 154
140
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136 135
120
140
160
180
200
220
240
260
0
5,000
10,000
15,000
20,000
25,000
30,000
1971 1975 1979 1983 1987 1991 1995 1999 2003 2007 2011 2015 Per Capita Treated Water Use (gallons per capita per day)Annual Volume of Treated Water Use, Acre-FeetWatering restrictions imposed in 2002
Three-tiered increasing block rates imposed in 1988
New Water Budgets
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Figure 4-2: Boulder’s Peak Day Use, 1971-2015
4.6 Water Use by Customer Sector
Figure 4-3 shows the average amounts of water use per year by Boulder’s major customer
sectors between 2012-2015. SF is the largest customer use category with an average water use
of 6,535 acre-feet, comprising 40 percent of total water use. The CII sector is the second largest
category, comprising 30 percent of water use at 5,035 acre-feet, followed by MF and municipal,
respectively. Overall, residential use represents approximately 65 percent of total water use.
Figure 4-3: Average 2012-2015 Water Use by Customer Sector
0
10
20
30
40
50
60
1971 1975 1979 1983 1987 1991 1995 1999 2003 2007 2011 2015Peak Day Use, MGDWatering restrictions imposed in 2002
CII5,035 AF30.5%
MFR4,224 AF 25.6%
SFR6,535 AF39.6%
Municipal726 AF4.4%Commercial/Industrial/Institutional (CII)
MultifamilyResidential (MFR)
Single FamilyResidential (SFR)
Municipal
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The University of Colorado is the largest single water user in Boulder, followed by city
municipal uses (principally outdoor use by Parks and Transportation), IBM and the Boulder
Valley School District, although no single customer represents more than 6 percent12 of total
water use. Table 4-1 lists Boulder’s largest individual water use customers, based on 2015 water
use data. As part of its auditing program for CII water customers, the city’s Water Conservation
Program works actively with the city’s large water use customers to identify water savings
potential specific to the customer’s circumstances.
Table 4-1: Boulder’s Largest Water Use Customers
User name
Consumption
(kgal) University of Colorado 272,468 City of Boulder (all Departments) 257,012 IBM Corporation 121,018 Boulder Valley Schools 76,853 NIST 44,590
As shown in Figure 4-4, water use in each customer sector has declined significantly since 2002,
although the relative proportions of water use among the sectors have remained fairly constant.
Figure 4-4: Pre-2002 and Current Water Use by Customer Sector
4.7 Indoor and Outdoor Water Use
Boulder’s annual indoor water uses from 1971 to 2015 are shown in Figures 4-5 through 4-7.
Indoor use averages 64 percent of Boulder’s total use, with relatively little variation from 1971-
2015. From 1971 to 2000, Boulder’s indoor use grew rapidly in response to a 46 percent growth
in population and a 170 percent growth in jobs. Boulder’s jobs/population ratio increased from
0.56 to 0.94 between 1980 and 2000 as Boulder became a regional employment center13. This
caused an increase in Boulder’s per capita indoor use as well as total indoor use. From 2001-
12 Source: City of Boulder Water Conservation Plan, August 2009.
13 Trends Report, BVCP 2005 Major Update.
0
1,000
2,000
3,000
4,000
5,000
6,000
7,000
8,000
9,000
CII MFR SFR MunicipalTreated Water Use, Acre Feet1994-2001 Average 2012-2015 Average
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2015, Boulder’s population grew at a lower rate while Boulder’s jobs/population ratio remained
fairly steady between 0.87 and 0.92. In spite of continued growth, Boulder’s total and per capita
indoor uses declined by 25 percent over this period in response to Boulder’s Water Conservation
Program, regional drought awareness efforts, and widespread availability of water-efficient
fixtures and appliances, which have resulted in water savings from replacement of older less-
efficient models. Further reductions in per capita indoor use are expected as older appliances
and fixtures continue to be replaced with more water-efficient models.14,15
Figure 4-5: Indoor Water Use as a Percent of Total Use
14 Several key legislative acts and government programs promote replacement of fixtures and appliances with more
efficient models. These include the 1992 National Energy Policy Act, the 2009 US DOE Energy Efficient Appliance
Rebate Program, the Energy Star Program, the Consortium for Energy Efficiency Standards, and Colorado Senate Bill
14-103, which prohibits the sale of fixtures that do not meet EPA’s WaterSense standards.
15 The continued reduction in indoor water fixtures and appli ances statewide is supported in Colorado’s Water Plan
and the CWCB’s SWSI 2010 Municipal and Industrial Water Conservation Strategies.
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
1971 1975 1979 1983 1987 1991 1995 1999 2003 2007 2011 2015
Watering restrictions imposed in 2002
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Figure 4-6: Annual and Per Capita Indoor Water Use
Figure 4-7: Per Capita Indoor Water Use by Customer Sector
Boulder’s annual and per capita outdoor uses from 1971 to 2015 are shown in Figures 4-8 and 4-
9. Annual outdoor use fluctuates much more than indoor use, in response to varying irrigation
water requirements. Boulder’s annual outdoor use generally grew from 1971 through 1988 due
to population growth and development of Boulder’s service area. Outdoor use held relatively
60
70
80
90
100
110
120
130
140
150
160
0
2,000
4,000
6,000
8,000
10,000
12,000
14,000
16,000
18,000
1971 1975 1979 1983 1987 1991 1995 1999 2003 2007 2011 2015 Per Capita Indoor Use, gpcdAnnual Volume of Indoor Use, Acre-FeetIndoor Use, AF Per Capita Indoor Use
1980 jobs/population
ratio = 0.56
1990 jobs/population
ratio = 0.74
2000 jobs/population
ratio = 0.94
2001-2015: jobs/pop.ratio
relatvely steady between 0.87
and 0.92
20
30
40
50
60
70
80
90
2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015gallons per capita per daySFR MFR CII
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steady from 1988 through 2001 despite continued population growth, as indicated by the
generally declining outdoor per capita uses in Figure 4-9. Reduction in per capita outdoor use
during this period is attributed to the effects of Boulder’s inclining block rates as well as
increased infill of Boulder’s service area, which reduced the amount of irrigated land per capita.
Outdoor use declined drastically in 2002 in response to Boulder’s water use restrictions that year.
As shown in Figure 4-9, Boulder’s per capita outdoor use declined from an average of 67 gpcd
during 1988-2001 to 40 gpcd during 2002. Since 2002, the trend in outdoor use has been upward
although outdoor remains well below pre-2002 levels. Per capita outdoor use averaged 53 gpcd
during 2012-2015, a 20 percent reduction from the 1988-2001 average, in spite of average IWR
being greater in 2012-2015 than in 1988-2001.
Annual fluctuations in outdoor use are due to customer’s responses to annual variations in
irrigation requirements. Outdoor water use is lower in relatively cool wet years and greater in
relatively warm, dry years. The year 2002 was an exception, when mandatory watering
restrictions reduced outdoor use in spite of high irrigation requirements. This is evident by
comparing 2002 to 2012, which was also a warm and dry year. No watering restrictions were
enacted in 2012, resulting in a much higher per capita outdoor water use compared to 2002
despite the fact that water budgets, a 5-tier block rate structure and a higher cost per 1,000
gallons of water were in place in 2012.
Figure 4-8: Annual Outdoor Water Use and Irrigation Water Requirement
0%
20%
40%
60%
80%
100%
120%
140%
0
2,000
4,000
6,000
8,000
10,000
12,000
1971 1975 1979 1983 1987 1991 1995 1999 2003 2007 2011 2015 Irrigation Water Requirement, Percent of 1950-2015 AverageAnnual Outdoor Water Use (Acre-Feet)Annual Outdoor Use Irrigation Water Requirement
Watering restrictions imposed in 2002 Waterbudgets
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Figure 4-9: Per Capita Outdoor Water Use, Irrigation Water Requirement and Trends
Appendices D, E and F provide graphs showing indoor/outdoor use ratios and annual indoor and
outdoor water uses for individual customer sectors for 2000-2015. Outdoor uses were
significantly reduced in all customer sectors during 2002 through 2004, in response to the city’s
2002 mandatory water restrictions and continuing drought awareness efforts.
5 Future Water Demands
5.1 Background
Municipal water supply planning in the Intermountain West has always had to deal with the
uncertainties of erratic and variable supplies, a growing population that is susceptible to boom-
bust cycles; and water use factors affected by customer behavior and variable outdoor watering
needs. Traditional planning approaches sought to minimize those uncertainties. Typically, a
single projection of future population was made, based upon historical growth, that stretched
thirty or more years into the future. Historical water use factors were assumed to continue
unchanged throughout the future planning horizon. The need for future water supplies and
facilities was then determined assuming that the supply system should be sufficient to meet
unrestrained water demand through a specified “worst case” drought (the 1950s drought was
typically assumed for planning purposes in the South Platte basin).
Such efforts often resulted in over- or under-building of water supply systems, if population
growth exceeded expectations or failed to materialize as planned. Drought restrictions, whether
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
110%
120%
130%
20
30
40
50
60
70
80
90
100
1971 1975 1979 1983 1987 1991 1995 1999 2003 2007 2011 2015
Irrigation Water Requirement, Percent of 1950-2015 AveragePer Capita Outdoor Use, gpcpdPer Capita Outdoor Use, gpcpd Average Per Capita Outdoor Use, 1988-2001
Average Per Capita Outdoor Use, 2012-2015 Irrigation Water Requirement, % of Average
Average IWR, 1988-2001 Average IWR, 2012-2014
53 gpcd
67 gpcd
94% of average
96% of average
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due to droughts more severe than anticipated or due to unexpected population growth coinciding
with drought, invariably resulted in negative customer reactions.
Boulder has been a leader in departing from tradition in its water supply planning. Starting with
its Raw Water Master Plan (RWMP) in the 1980s, Boulder recognized that no municipal water
supply can ever be 100 percent reliable against all droughts and that the environmental and
economic costs of reducing the risks of occasional water restrictions are significant. Boulder
recognized that certain water uses (such as drinking water and firefighting) required an assured
supply whereas other uses (such as lawn watering) can tolerate occasional restrictions.
Boulder therefore adopted reliability criteria that allowed for varying degrees of occasional water
supply restrictions in response to droughts of varying severity. This required a fundamental
change to Boulder’s planning approach. Beginning with the RWMP in 1988, Boulder discarded
the static approach of considering only recorded historical droughts and instead explicitly
incorporated synthetic hydrology and paleo-hydrology derived from tree rings into its modeling
of water supply. Boulder incorporated expected savings from conservation programs and water
use trends into its demand projections. Beginning with its Drought Plan in 2003, Boulder
incorporated the potential effects of a range of climate change scenarios into its modeling of
water supply reliability. Beginning with its Climate Change Vulnerability Study in 2007,
Boulder identified “no regrets” short term actions that would decrease the city’s vulnerability to
climate change without major or irrevocable commitments of resources. Boulder continues to
use a single projection of population and employment growth in its water supply planning, which
is due to a city-wide requirement that all master plans utilize the city’s officially adopted
demographic projections that are updated every five years as part of the BVCP update process.
5.2 Scenario Planning
The Colorado Water Plan, formally adopted by the Governor in 2015, recommends that water
planners include scenario planning in assessments of future water needs. The scenario planning
concept involves planning in a way that can adapt to multiple future scenarios rather than trying
to predict and plan for a single “most likely” or “worst case” future scenario as has been the
traditional approach. The scenario planning model is conceptually illustrated in Figure 5-116.
As described in Section 5.1, the city’s reliability criteria exemplify the scenario planning concept
because they allow the city to adapt to a myriad of future water scenarios. The Water
Conservation Program is key to providing the flexibility needed to adapt to an uncertain future
both through implementation of the city’s drought plan during dry periods and in strategic
planning in general. For example, if it is cooler and wetter than expected, outdoor landscaping
programs may be less of a focus. However, if it were extremely hot and dry, code changes may
need to be implemented to more directly reduce outdoor water consumption. In either case, the
near-term, no-low regrets strategies will benefit the utility under any future scenario, and the
Water Conservation Program will be the mechanism through which the strategies will be shaped
and implemented.
16 Adapted from Marra and Thomure, 2009
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Figure 5-1: Adaptive Scenario Planning
The city’s demographic projections are normally made as far into the future as necessary to reach
a “build-out” or zoning capacity condition. The city’s most recent projections assume that
residential and non-residential growth will reach Boulder’s respective zoning capacities by
approximately 2040 and 2080, respectively. The city’s current planning horizon is therefore 64
years, through the year 2080. Within that horizon and for the purposes of water demand
management, appropriate near-term, no-low regrets plans and milestones for Boulder would be:
(1) completion of the city’s updated climate change modeling effort and water supply reliability
assessment, which is expected later in 2016; (2) an update of the city’s water supply reliability
assessment using the next update of the city’s demographic projections, which is expected as part
of the 2020 update of the BVCP; and (3) development and submittal of the city’s 2023 WEP.
As discussed in Section 0, the city’s updated climate change modeling effort will utilize the most
recent climate change modeling and downscaled hydrology data, along with the city’s current
demographic projections and projected water use factors to assess the reliability of Boulder’s
water supply system. This analysis will incorporate projected water demands that reflect the
expected passive savings from continued natural replacement of fixtures and appliances was well
as expected active savings from the city’s ongoing Water Conservation Program. This effort will
provide a comprehensive analytical platform for evaluating the potential need for additional
water conservation goals.
As part of the BVCP update, Boulder is actively evaluating several focus areas including
community resilience, the need for additional and more diverse housing and major
redevelopment projects. The results of this process may lead to significant changes to the city’s
demographic and land use projections, which would affect water demands.
Development of the city’s 2023 WEP will provide a well-timed opportunity to re-examine the
city’s existing water conservation goal and programs, considering the results of the updated
Future
Signposts
Near-Term Longer-Term
Robust/
No & Low
Regret
Actions
Contingent/Adaptive
Actions
D
A
C
E
B
2016
2050
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climate modeling and BVCP update.
Scenario Factors for Affecting Water Demand
The city projects its future water demands based on projected population and employment within
its service area and expected per capita water use factors for each of its customer sectors17. Both
the city’s demographic projections and the water use factors are subject to new information and
several areas of uncertainty. Boulder’s future water demands were most recently projected in
Boulder’s 2011 WUMP. The city’s future water demand projections are updated in this 2016
WEP in order to reflect changes and updated information in the areas listed below that will affect
future water demand, including the expected savings attributable to Boulder’s active water
conservation activities. Each of these factors is likely to affect Boulder’s future water demands.
Demographic and Land Use Projections. The city’s demographic and land use
projections were updated and substantially modified in August 2015 as part of the 2015
update of the BVCP.
Baseline Per Capita Water Uses. Boulder’s historical per capita water uses have
declined significantly since 2006-2009, which formed the water use basis for the
WUMP’s future water demand projections. In this 2016 WEP, Boulder’s baseline per
capita uses are based upon historical uses for 2012-2015.
Natural Replacement of Fixtures. With the passage of Colorado Senate Bill 14-103
and the updates to EPA’s WaterSense specifications, the demand-reducing effects of
ongoing natural replacement of water fixtures will be greater than previously considered.
Expected Savings from the City’s Water Conservation Program. Several ongoing
components of the city’s Water Conservation Program are expected to result in water
savings in addition to those attributable to natural replacement of water fixtures.
Climate Change Effects on Projected Water Demands. There is a reasonable basis for
projecting the range of likely climate change effects on Boulder’s future water demand.
Boulder’s future water demands are projected, incorporating the most recent information in each
of these five areas. The resulting range of projected water demands illustrates the scope of
Boulder’s likely potential water demand futures.
5.3 Demographic and Land Use Projections
The city’s demographic projections were updated in August 2015 as part of the 2015 update to
the BVCP, and are shown in Table 5-1. The updated projections are based upon current zoning
and land use regulations in Planning Areas I and II as currently defined. According to the
projections, Boulder will reach its residential zoning capacity by 2040, but will not reach its
zoning capacity for additional jobs until approximately 2080.
17 The use of per capita water use factors for projecting residential water demand has been cautioned by some
researchers because of the nonlinear relationship between household size and per capita water use: household water
use does not increase in proportion to household size. This is not a concern in Boulder’s case because average
household size is projected to remain constant.
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Table 5-1: The City of Boulder’s Demographic Projections
Sources: 2015-2040 Projections, Updated 8/28/15, Boulder Valley Comprehensive Plan. Boulder Valley Comprehensive Plan – 2015 Housing Unit, Population, and Employment Estimates and Projections Methodology. https://bouldercolorado.gov/pages/2015-bvcp-phase-i-foundations-work
The city’s updated demographic projections assume some amount of increased housing density,
primarily via redevelopment in select locations, mostly along major corridors and/or in mixed
use areas that are already relatively highly developed. Therefore, it is not anticipated that
Boulder will experience a significant reduction in average irrigated area per household despite
increased densification. Also, the city’s updated demographic projections assume no change in
the average number of persons per household. Therefore, no significant reduction in per capita
water use is currently expected due to changes in land use patterns.
Some uncertainties exist in the city’s demographic and land use projections. For example,
Boulder may decide to modify its zoning and development regulations to allow for increased
housing density in residential areas, or conversion of non-residential areas into residential or
mixed-use areas, in order to achieve a better balance between employment and housing. Boulder
formally modifies its demographic projections as part of the update of the BVCP, which has
occurred every five years since 1990. The city’s current projections are assumed for the purpose
of this WEP, consistent with Boulder’s planning guidelines. It is anticipated that Boulder will
update its demographic projections prior to the next update of the WEP in 2023, and those
updated demographic projections will be reflected in the next WEP update.
5.4 Baseline Per Capita Water Uses
A characterization of Boulder’s existing water use and water use factors is necessary to provide a
known starting point for future water demand and supply and management planning. For the
purposes of this 2016 WEP, Boulder’s current baseline water use is calculated as the average of
historical 2012-2015 water uses, normalized for IWR. Boulder’s current baseline water use is
shown in Table 5-2, disaggregated by customer sector and indoor vs. outdoor use. It should be
noted that residential uses are shown in two ways: separated into SF and MF components and
also as combined residential uses. As previously discussed, per capita values for SF and MF
water uses are questionable due to disparities in calculation methods, which probably result in
erroneously high SF per capita values and erroneously low MF per capita values. This issue has
Existing
Additional
to 2040 2040 Total
Additional
to Zoning
Capacity
Zoning
Capacity
Total
Dwelling UnitsCity Limits (Area I and III Annexed) 45,740 6,260 52,000 - 52,000Area II 5,710 490 6,200 - 6,200
Total Service Area 51,450 6,750 58,200 - 58,200
Population (includng group quarters)City Limits (Area I and III Annexed) 104,810 18,190 123,000 - 123,000Area II 12,030 1,070 13,100 - 13,100
Total Service Area 116,840 19,260 136,100 - 136,100
EmploymentCity Limits (Area I and II Annexed) 98,510 18,490 117,000 34,200 151,200Area II 2,920 580 3,500 1,800 5,300
Total Service Area 101,430 19,070 120,500 36,000 156,500
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been addressed for future water demand projection purposes by combining SF and MF water
uses and populations and projecting residential SF and MF demand on a lumped basis.
Table 5-2: Baseline Water Use (Normalized 2012-2015 Average)
In the context of Colorado’s Water Plan, Boulder’s baseline water use has already attained the
South Platte Roundtable’s water conservation goal for 2050 (145 gpcd total demand)18.
5.5 Natural Replacement of Fixtures and Appliances
Boulder’s indoor water use has been and will continue to be affected by national and regional
trends in technology and regulations that have resulted in significant reductions in indoor per
capita use. National water use surveys and water demand trends along the Front Range have
shown a significant decrease in indoor per capita water use over the past few decades. Most of
these reductions have been attributed to improved water efficiency technologies for indoor water
fixtures and appliances. The 1992 Federal Energy Policy Act, made effective in Colorado in
1994, required improved water efficiency standards for various fixtures and appliances including
toilets, faucets and showerheads.
Increased consumer confidence in these products, rebates supporting low-water products, the
possibility to save money on water (and energy) bills and drought have all led customers and the
market toward increasingly efficient products. Additionally, because older inefficient models are
no longer allowed to be sold, there is now an ongoing natural replacement rate of these higher
efficiency products. This trend helps reduce the burden on utilities to have to incentivize indoor
efficiency and new laws ensure that higher efficiency products will remain the standard.
Colorado Senate Bill 14-103, passed into law in 2014, requires that plumbing fixtures sold in
Colorado meet the standards set by the U.S. EPA’s WaterSense partnership program. For
18 Colorado’s Water Plan, Figure 6.3.1-1.
Customer Sector Acre-Feet
Per Capita,
gpcdSFR Indoor 3,276 61SFR Outdoor 3,309 62SFR Total 6,585 123MFR Indoor 2,842 38MFR Outdoor 1,455 19MFR Total 4,297 58All Residential Indoor 6,118 48All Residential Outdoor 4,764 37All Residential Total 10,882 85CII Indoor 3,447 30CII Outdoor 1,639 14CII Total 5,086 44Municipal Indoor 94 0.7Municipal Outdoor 637 5.0Municipal Total 731 5.7Unaccounted-for 1,636 13Total All Sectors 18,335 143
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residential fixtures, the current WaterSense standards specify a maximum of 1.28 gallons per
flush for flush toilets, 1.6 gallons per minute for lavatory faucets and 2 gallons per minute for
showerheads. These WaterSense standards are more stringent than those set by the 1992 Federal
Energy Policy Act. Efficiency improvements to fixtures and appliances continue to occur such
that some of the current best available technologies on the market exceed the WaterSense
standards.19 Furthermore, additional legislation has been passed to incentivize continued
improvements in water efficient fixtures and appliances20.
The expected continuing effects of natural replacement on indoor residential use in Boulder were
evaluated based upon two studies done by Aquacraft Water Engineering and Management 21 that
directly measured water use in single family homes.
In the USEPA Combined Retrofit Report, Aquacraft measured indoor water use in 100 homes in
three utilities before and after a high-efficiency fixture and appliance retrofit. Before the retrofit,
the water use in these homes was similar to what was found in the 1999 Residential End Uses of
Water Study (REUWS). After the retrofit, indoor water use in these homes was reduced by more
than 30 percent - to an average of 39 gpcd. In a second study, Aquacraft measured water use by
36 new homes built to meet the WaterSense new home specification (as of 2009), with the
addition of a high-efficiency Energy Star–rated clothes washer. Indoor water use for this sample
of homes averaged 36 gpcd.
Indoor Trends and Assumptions
Given that Colorado Senate Bill 14-103, will result in all residential water fixtures being at least
as efficient as the WaterSense specification, it was assumed that natural replacement of aging
water fixtures will result, by the year 2050, in all residences and group quarters in Boulder
having water fixtures that meet WaterSense standards, and that 50 percent of all residences and
group quarters will also have high-efficiency Energy Star water appliances. These assumptions
result in an expected average residential indoor use of 39 gpcd by 2050, which represents a 19
percent reduction from the current baseline indoor residential per capita use.
The CII sector includes a wide range of business and service activities, and CII indoor water use
is much more varied than residential indoor use. Industrial indoor water use is typically for four
primary functions: heating and cooling, industrial process water, washing, and as an ingredient.
Commercial and institutional indoor water use is typically for domestic purposes and for heating
and cooling. The typical water savings potential for CII use has been estimated in the range of
19 The city is currently working with the CRC in distributing 0.8 gallons per flush toilets to customers. These toilets
exceed the 1.28 gallon per flush WaterSense standard and the 1.28 gallons per flush toilet currently available on the
market to the general public.
20 Several key legislative acts have or will influence the rate and type of fixtures and appliances that will be replaced
These include updates to the 1992 National Energy Policy Act, 2002 California Energy Commission (CEC) Water
Efficiency Standards, 2007 California Assembly Bill 715, the 2009 US Department of Energy State Energy Efficient
Appliance Rebate Program and Colorado Senate Bill 14-103. Additionally, EPA’s WaterSense partnership and the
Energy Star Program and the Consortium for Energy Efficiency Standards play a role in incentivizing water efficient
fixtures and appliances. The continued reduction in indoor water fixtures and appliances statewide is also supported
in CWCB’s SWSI 2010 Municipal and Industrial Water Conservation Strategies. The city participated on the
Stakeholder Advisory Board providing predictions for replacement penetration rates by 2050.
21 DeOreo, William B., and Peter W. Mayer, June 2012.
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15 percent to 35 percent22. The effects of natural replacement of water fixtures and appliances
on CII indoor water use has not been widely studied. Over the past 20 years, average CII per
capita use in the Boulder service area has declined by 29 percent to 44 gpcd, including a 24
percent drop in indoor use (to 30 gpcd) and a 37% drop in outdoor use (to 14 gpcd), as a result of
natural replacement and Boulder’s water conservation efforts including its water budget rate
structure. It is assumed that continued natural replacement will result in an additional 5 percent
reduction in CII indoor per capita use by 2050.
Municipal indoor water use is a mixture of residential and commercial types of water uses and is
expected to experience a reduction due to natural replacement that is between the expected
reductions in residential and CII uses. It is assumed that the effects of natural replacement will
result in an additional 12 percent reduction in municipal indoor per capita use by 2050.
It should be noted that the projected reductions in indoor per capita uses discussed above do not
necessarily mean that Boulder’s projected water demands will decrease, only that the per capita
indoor uses are likely to decrease. Boulder’s total water demands are projected to increase even
with reduced per indoor capita use assumptions, because of projected increases in population and
employment and because of the expected effects of climate change.
Table 5-3 shows the reductions in indoor per capita uses by customer sector that are expected to
occur by 2050 in Boulder due to natural replacement of fixtures and appliances.
Table 5-3: Expected Reductions in Indoor Per Capita Uses from Natural Replacement
Per Capita Use
(gpcd)
Indoor
Residential
Indoor
CII
Indoor
Municipal Baseline (2012-2014) 48 30 0.74 Expected 2050 39 28.5 0.65 Expected Reduction 9 1.5 0.09
Outdoor Trends and Assumptions
Unlike indoor uses, there does not appear to be any clear trend in outdoor uses that is attributable
to passive savings from enhanced urban irrigation technologies. While such technologies
certainly exist and are finding their way into the market, their meaningful effect on outdoor water
use at scale seems to be dependent upon active conservation program measures that effectively
promote their use. Therefore, no passive savings were assumed for outdoor uses.
On May 12, 2016, Colorado legalized the use of residential rain barrels in the state. The city
does not expect that the use of residential rain barrels will result in a major savings of treated
water23. However, rain barrel use will factor into the city’s planning as an education tool that
can help provide customers with a suite of outdoor water saving options.
22 Vickers, 2002.
23 Assuming a daily rainfall of 0.1 inches as the minimum necessary to allow filling of rain barrels, deployment of two
42-gallon barrels per participating household, and a 50% participation rate by residential dwelling units, residential
rain barrel collection could produce up to an annual average of 187 ac re-feet of nonpotable irrigation supply per
irrigation season, which would be equal to approximately 2.7% of Boulder’s existing outdoor use.
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5.6 Water Conservation Savings
5.6.1 Savings Attributed to Boulder’s Water Conservation Efforts
Colorado's statutes require that water providers quantify, to the degree reasonably possible, the
water savings attributable to their previous demand management efforts. Boulder has had a
Water Conservation Program in place since 1992. Boulder’s water uses have declined
significantly between 1992 and 2009 as evidenced by the significant drop in total and per capita
uses as described in Section 4. Part of that decline is reasonably attributable to the efforts of
Boulder’s Water Conservation Program, but sufficient data are not available to specifically
quantify those savings. Since the 2009 WCP, the city has monitored activities under its Water
Conservation Program measures and has estimated the water savings from each of those
measures as summarized in Table 5-5. Boulder’s Water Conservation Program has undoubtedly
had a major effect on Boulder’s water uses, however, the full impacts of its collective outreach,
education and targeted initiatives are not as easily measured compared to program specific
savings. Boulder annually reports its water uses, water conservation activities and estimated
savings due to its Water Conservation Program to the CWCB pursuant to Colorado’s reporting
requirements for water use and water conservation data (Colorado HB10-1051).
Table 5-4: Estimated Savings from Boulder’s Water Conservation Program Since 2009
5.6.2 Projected Future Savings from Water Conservation
The city’s Water Conservation Program includes several ongoing measures and partnerships that
actively promote conservation savings beyond that projected from natural replacement. These
include partnerships with the Center for Resources Conservation (0.8 gpf toilet installs, Garden-
in-a-Box landscaping kits, and Slow-the-Flow landscaping sprinkler consultations), and Partners
for a Clean Environment (indoor audits for CII customers including installations of commercial
pre-rinse spray valves, aerators and showers). The city’s SmartRegs and Green Points programs
also specify water efficiency standards for new residential construction, major remodels and
residential rentals that include ultra-low flow toilets and EnergyStar washing machines. The
city’s Water Conservation Program also includes a water loss auditing and monitoring program
Year
Utilities
rebate/
service
programs
Partner
rebate/
service
programs
CRC
Garden-in-
a-box
CRC
irrigation
system
audits
Annual
Savings,
Total
Cumulative
Savings,
Total200910.1 0.0 0.1 1.3 11.6 11.6201022.0 0.0 0.2 1.5 23.7 35.2201114.8 1.6 0.2 1.6 18.3 53.5201210.5 4.2 0.3 1.7 16.8 70.320135.3 5.8 0.5 1.9 13.4 83.720140.0 9.2 0.7 1.8 11.7 95.420150.0 9.4 1.0 2.0 12.3 107.7Total62.7 30.1 3.0 11.8 107.7 215.5
Estimated Water Conservation Savings, AF
1. Since 2012, Utilities rebate programs have largely been shifted to partnership organizations.2. Programs include PACE (pre-rinse spray valves, aerators and showerehads), LEAD (clotheswashers, faucets and showerheads) and CRC (0.8 gpf toilets).
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that is supported by Utilities’ capital improvements program and is expected to gradually reduce
the city’s water loss to below 6 percent of treated water production. Based upon recently
reported savings by the two partnership programs and assuming a 2 percent annual growth in
their effective operations, the additional projected water savings resulting from the continued
operation of the city’s existing Water Conservation Program are shown below. Savings are
projected to occur linearly from 2015 through 2050, similar to the effects of natural replacement.
Table 5-5: Expected Reductions in Per Capita Uses from Active Water Conservation
Per Capita Use (gpcd)
Indoor
Residential Indoor CII
Indoor
Municipal
Outdoor
Residential
Water Loss
(percent) Baseline (2012-2015) 48 30 0.74 37 9% Expected 2050 with Natural Replacement 39 28.5 0.65 37 9%
Expected Reduction with Natural Replacement 9 1.5 0.09 0 0%
Expected 2050 with Natural Replacement and Active Conservation 36 25.5 0.60 36,1 6%
Expected Incremental Reduction from Active Conservation 3 3 0.05 0.9 33%
5.7 Climate Change Effects on Projected Water Demands
There is now broad recognition that the future climate will be different than the past and that this
will affect water demands and supplies. The potential effects of climate change should be
considered in Boulder’s water demand projections. More than one third of Boulder’s water use
is outdoor irrigation use, which is a function of IWR. A warmer climate will increase IWR,
which will in turn increase outdoor water demand, assuming there is no change in the extent,
type, code requirements for, or customer values placed on Boulder’s urban landscaping.
The Colorado River Water Availability Study (CRWAS) incorporates the most recent range of
peer-reviewed climate projections and provides downscaled modeling of temperature,
precipitation and crop irrigation requirement (similar to IWR) for Colorado. While there is
significant variability and uncertainty in CRWAS’s climate projections, there is universal
agreement among the projections that all areas of Colorado will be warmer in the future, as
shown in Figure 5-2. For the Boulder area, the average of the CWAS projections show an
increase in mean annual temperature of 3.4 degrees F by 2040 and 5.3 degrees F by 2070. This
is consistent with the 2015 Colorado Climate Plan projections of 2.5 – 5.5 degrees F by 2050
which were also used to inform the Colorado Water Plan.
The outlook for future precipitation is less clear; as illustrated in Figure 5-3, the range of CWAS
projections show both increases and decreases in future mean annual precipitation, although
most of the projections show increased precipitation occurring primarily in the winter months.
The CRWAS modeling also projects future IWR, which integrates the effects of temperature and
precipitation change. The April-October IWR for the Boulder area, as modeled by CRWAS,
also varies widely as shown in Figure 5-4, although the average IWR is projected to increase
significantly as shown in Table 5-4. As the table shows, the climate projections show relatively
wide range of potential change in IWR, including potential increases or decreases. Given the
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uncertainties in climate modeling, the full range of potential change in IWR should be the focus
of planning rather than any particular projection.
Table 5-6: Projected Percent Change in April-October IWR for Boulder
The range of projected changes in IWR was incorporated into the future water demand
projections by proportionately increasing the outdoor demands to reflect the average, maximum
and minimum projected changes in IWR by 2040 and 2070.
Figure 5-2: Range of Projected Average Monthly Temperature with Climate Change for
Boulder, Year 2070
Year
Average of
Projections
Maximum
Projected
Minimum
Projected20408.4% 30.8% -15.5%2070 11.7% 45.2% -20.8%
0
10
20
30
40
50
60
70
80
90
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov DecAverage Temperature in FahrenheitHistorical Average Temperature 1949-2010 1st Percentile
25th percentile 50th percentile
75th percentile 99th percentile
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Figure 5-3: Range of Projected Average Monthly Precipitation with Climate Change for
Boulder, Year 2070
Figure 5-4: Range of Projected Average Monthly IWR with Climate Change for Boulder
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov DecAverage Total Monthly Precipitation in inchesHistorical Average Precipitation 1949-2010 1st percentile
25th percentile 50th percentile
75th percentile 99th percentile
-1
0
1
2
3
4
5
6
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov DecAverage Total Monthly CIR in inchesHistorical Average CIR 1949-2010 1st percentile
25th percentile 50th percentile
75th percentile 99th percentile
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5.8 Projected Water Demands
Figure 5-5 and Table 5-7 show Boulder’s projected water demands reflecting the combined
effects of the city’s updated demographic projections, Boulder’s updated baseline water use
(normalized average 2012-2015), the expected effects of continued natural replacement of water
fixtures and appliances, the projected additional savings from the city’s active Water
Conservation Program elements, and the range of expected climate change effects upon outdoor
water uses. Boulder’s historical water uses since 1990 and the WCFS’s previous water demand
projection for the Comprehensive Scenario are also shown for comparison purposes. It should
be noted that the currently projected water demands assume average year-to-year weather
conditions (as affected by climate change), whereas the historical water uses reflect actual
weather conditions, which caused outdoor water uses to vary significantly from year to year.
As shown in Figure 5-5, Boulder’s water demands are projected to increase going forward as a
function of projected population and employment growth and climate change effects, following a
period of significant decline in use from 2000 through 2004 and then a period of relatively steady
use from 2004 through 2015.
The changes in slope in the lines for projected demands that occur in 2040 reflect the assumption
that Boulder’s population will reach its zoning capacity by 2040. The changes in slope in 2050
reflect the assumption the savings from the city’s current active Water Conservation Programs
and from natural replacement of fixtures and appliances will reach 100 percent penetration by
2050. The flattening of the lines in 2078 reflect the assumption that employment growth in
Boulder will reach its zoning capacity by 2078.
Figure 5-5: Projected Water Demands
23,717
19,980
23,908
20,997
18,171
16,000
17,000
18,000
19,000
20,000
21,000
22,000
23,000
24,000
25,000
1990 2000 2010 2020 2030 2040 2050 2060 2070 2080Historical Use/Projected Demand (AF)Projected demand with existing (2012-2015 average) per capita use factors
Projected demand with conservation and natural replacement
Projected demand with conservation, natural replacement & climate change (maximum of model results)
Projected demand with conservation, natural replacement & climate change (average of modeled results)
Projected demand with conservation, natural replacement & climate change (minimum of modeled results)
Historical use
Projected demand, WCFS Comprehensive Scenario (did not address climate change)
residential zoning capacity assumed to be reached by 2040
savings from active conservation and natural replacment assumed to reach 100% by 2050
non-residential zoning capacity assumed to be reached by 2078
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Note: the “jump” between historical 2013-2014 demands and projected 2015 demand is due to the fact that IWR and associated outdoor use were significantly below average in 2013 and 2014, whereas proje cted demand in 2015 assumes average IWR and associated outdoor demand.
Table 5-7: Boulder’s Projected Future Water Demands
6 Planning Considerations
The primary purpose for the city’s water conservation goal and program is to help assure that
Boulder’s water supply system will operate in a manner that meets the city’s adopted reliability
criteria in the face of variable water supply and demand conditions while satisfying the
reasonable needs of its customers. Boulder’s water conservation goal and program should also
appropriately consider the city’s other goals related to carbon footprint reduction, stormwater
management/green infrastructure, instream flows and support of local agriculture, as well as
regional and State water conservation objectives.
A Water Conservation Program plays an important role in demand management, outreach and
education. A variety of factors are considered in developing future water conservation goals and
options. Below are a series of questions that should be considered in developing new water
conservation goals and programs.
1. How does water conservation affect water supply reliability and drought management?
2. Does Boulder need to set new water conservation goals based on findings in the 2009 WCP,
2011 WUMP and given current projected water use?
3. Will sufficient indoor water savings be achieved through natural replacement of fixtures and
appliances?
4. What role does overall level of urban landscaping play in defining Boulder’s quality of life?
To what degree should additional outdoor water conservation be emphasized in the city’s
water conservation plan, and who should decide?
5. How can the Water Conservation Program align efforts with stormwater and other water
quality programs?
6. How does Boulder’s water conservation interact with energy consumption and production
and greenhouse gas (GHG) emissions?
7. What are the water rights implications of water conservation?
Some of these questions were previously addressed in this report. A summary of the salient
factors influencing Boulder’s decision to retain its current conservation goal and targets is
presented in the following sections. A discussion of other factors is presented in Appendix C.
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Water Conservation and Water Supply Reliability
The first three questions listed above focus on the primary role of water demand management in
helping to ensure the adequate reliability and resiliency of Boulder’s water supply. Boulder’s
Utilities division has developed sophisticated modeling capabilities for assessing the
performance and reliability of its water supply system, including the use of paleo-hydrology and
output from global climate change modeling. Boulder most recently conducted a formal
modeling assessment of its water supply reliability in 2008 as part of its climate change
vulnerability study24. That analysis assumed a buildout water demand of 26,000 acre-feet per
year. At that time, it was Utilities’ policy to add a 10 percent safety factor onto its projected
buildout demand to address potential modeling uncertainties, which resulted in a modeled
demand of 28,600 acre-feet per year.
As discussed in Section 5.8, Boulder’s water demand projections, reflecting the city’s most
recent demographic projections, the expected combined effects of the city’s ongoing Water
Conservation Program and natural replacement, and the range of projected climate change
effects, result in buildout demands ranging from approximately 18,200 AF to 23,900 AF per
year. As described in Section 3.3, attainment of Boulder’s existing conservation goal would
result in a buildout demand of approximately 25,000 AF per year, which is greater than the upper
end of the range of currently projected buildout demands. The combined savings from the city’s
ongoing Water Conservation Program and from natural replacement are expected to keep the
city’s future water demand below 24,000 acre-feet per year, even with the highest projected
increase in IWR due to climate change. Therefore, continuation of the city’s existing Water
Conservation Program will assure that the city meets its water conservation goal over the long
term and will provide a buffer against the possibilities that climate change may result in warmer
futures than currently projected and that Boulder may consider modifying its zoning capacity or
service area to accommodate additional population than currently projected. Continuation of
Boulder’s existing Water Conservation Program makes sense as part of a no-low regrets strategy.
Boulder is in the process of updating its water supply system modeling to incorporate the latest
peer-reviewed climate change modeling data and methods for assessing climate change effects
upon the reliability of Boulder’s raw water supply system, integrat ed with prehistoric natural
flows reconstructed from tree ring records to examine long-term hydrologic variability. This
assessment will help determine whether additional water conservation would be needed to meet
Boulder’s reliability criteria, and is expected to be completed end of 2016. The results of this
assessment will be used to consider whether new conservation goals should be adopted as part of
the city’s 2023 WEP.
Water Conservation and Urban Landscaping
The city’s existing 2009 WCP includes activities aimed at reducing outdoor uses, and long-term
attainment of Boulder’s existing water conservation goal will require restraint in outdoor uses.
Current water use trends indicate that Boulder has achieved, and is maintaining, its water
conservation goal in the near term. However, there has been a slight upward trend in per capita
outdoor uses since 2002, and expected climate change effects will continue to put upward
24 Smith et. al., 2009.
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pressure on Boulder’s outdoor uses. Additional water conservation efforts aimed at further
reductions in outdoor uses, if needed, should be sensitive to the value of urban landscaping as a
defining characteristic of Boulder’s quality of life as perceived by its citizens. Preliminary
analysis suggests that there is a wide range in the intensity of outdoor water use by Boulder’s
customers, and that some of Boulder’s customers over-irrigate significantly. More refined
studies of the amount of outdoor use needed to maintain the existing level of urban landscaping,
particularly the existing urban tree canopy and of opportunities to reduce outdoor use without
impairing the overall quality of urban landscaping would be beneficial. Boulder will continue to
monitor outdoor use and will adjust its water conservation efforts related to outdoor use as part
of an adaptable no-low regrets strategy. The need for additional outdoor water conservation
efforts will be revisited as necessary in the next WCP update.
Watershed Sustainability – The Water Conservation-Stormwater Nexus
The city’s Water Conservation Program, Stormwater Quality Program and Utility Outreach
Program historically coordinated on community engagement efforts. Recognizing greater
opportunities to leverage and enhance cross-program efforts, the city formally combined the
three programs under a single Watershed Sustainability and Outreach Program in 2013.
This restructuring would allow for greater flexibility and creativity around how these programs
are managed. For example, irrigation audits for water conservation could also be leveraged to
talk about nutrient runoff from fertilizers. Outreach efforts could be easily shifted from drought
to flood (as was the case in 2013). Instead of just promoting xeriscape, the city would have the
opportunity to explore low-water rain gardens that could support both water quantity and water
quality concerns.
As Boulder continues to grow, densification and land use changes will impact green spaces. Both
water conservation and stormwater implications must be considered as the city continues to
develop. This is particularly important with regards to ongoing city discussions around Green
Infrastructure opportunities and urban ecosystem health. Green Infrastructure installations have
multiple benefits including reduced runoff and reduced water use. If grass swales are installed
for water quality or flood mitigation efforts, the type of turf used could have drastically different
watering needs. If more trees are planted to improve urban ecosystem health and offset tree
deaths due to Emerald Ash Borer, the amount and types of trees used will impact water use.
Having the Water Conservation Program play an active role in these discussions will be
important to the ultimate success of these initiatives.
Water Conservation-Energy-Greenhouse Gas Nexus
As a leader in municipal efforts to reduce human impacts on climate, Boulder is taking action in
reducing its carbon footprint and is studying the feasibility of creating its own municipal utility.
The city’s activities in this area are described in Appendix C. Utilities works with other city
departments and is involved in city-wide initiatives to leverage synergistic opportunities and
minimize unintended consequences.
For example, the most water efficient washing machine might not be the most energy efficient.
Supporting models that have the highest water conservation and energy savings offers the
greatest benefit to the city and the community. Similarly, outdoor Water Conservation Programs
that result in customers replacing plant material with hardscapes, could decrease the cooling
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effect for surrounding buildings and increase energy use. Additional hardscapes would also
increase runoff from properties (see section above).
By reducing water use, water conservation has the potential to create net energy savings due to
the energy used for diversion, conveyance and treatment of Boulder’s source water supplies,
distribution of treated water, customers’ heating of treated water for various end uses, and
treatment of wastewater. In order to assess the potential fossil fuel energy reduction benefits of
water conservation, a preliminary energy budget analysis was conducted of the energy associated
with various water uses, compared to the energy produced by the city’s hydropower systems
embedded in the water supply delivery system. The details of this analysis are described in
Appendix C. Additional insight to the net amount of energy saved through water conservation
may also be obtained by developing quantitative estimates of the amount of energy used for
residential and CII customer end uses which require heating and industrial pre-treatment.
Considering all existing operations and water uses, Boulder’s water supply system and its
customers’ uses of water is definitely a net energy consumer, largely due to customers’ energy
use to heat delivered water for various end uses. However, at the margin, any reasonable mix of
water conservation measures is likely to result in only modest net energy savings (in range of
150 to 200 kWh per acre-foot of water conserved). This is because most of the expected savings
from water conservation will come from unheated water uses: low volume flush toilets;
xeriscaping and more efficient irrigation use; and reductions in distribution losses. Savings in
heated water uses are expected to be relatively limited, because the relatively high energy cost of
heated water use already serves as an incentive for efficient use, and because heated water uses
are typically highly valued by residential customers. The energy saved from the reductions in
water treatment and distribution, wastewater treatment and from the limited reductions heated
water uses, will largely be offset by reductions in hydropower production.
7 An Adaptive-Resilient Water Conservation Program
Since the drought of 2002 and in response to the recent large variations in weather conditions
from drought conditions during 2012 through early August 2013 followed by unprecedented rain
September 2013 and relatively wet conditions in 2014 and 2015, the Water Conservation
Program has operated in a manner that is both adaptive-resilient and supportive of other city
efforts and partnerships. Significant efficiencies and benefits were achieved by partnering with
other entities, including the Center for Resource Conservation (CRC), Local Environmental
Action Division (LEAD), Partners for a Clean Environment (PACE) and the County’s
EnergySmart Program. The elimination of the city’s rebate program in 2012 reflected recent
trends and statutory changes and re-focused rebate dollars on service-based programs in more
targeted areas. These innovative changes not only saved resources but also resulted in the city
receiving a 2013 EPA WaterSense Award for its efforts. Redeployed resources were used to
enhance service-based programs that provided greater value for customers in addition to adding
increased water loss monitoring, leak detection notifications and enhanced outreach to the city’s
largest water use customers.
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Maintaining Boulder’s Water Conservation Goal
After reviewing its water use trends, water demand drivers and projected water use, the city has
determined that its existing water conservation goal and associated water use targets represent a
prudent no-low regrets near-term strategy. While Boulder has met all but one of its water use
reduction targets based upon 2012-2015 uses, in some cases by considerable margins, Boulder
should monitor its per capita and total water uses to avoid “backsliding” in water use categories
where it has already achieved its water use reduction targets, while recognizing that climate
change will put upward pressure on per capita outdoor uses and ongoing water conservation
efforts and natural replacement will tend to reduce indoor per capita water uses.
Boulder’s near-term water use targets are expressed in terms of per capita uses, percent of treated
water production, and year 2022 total treated water demand in Table 7-1. These targets are
based upon Boulder’s 2012-2015 baseline per capita water uses, and are adjusted to reflect
expected increases in outdoor use due to climate change (the maximum of climate change model
results) and expected decreases in indoor uses and water loss due to water conservation and
natural replacement.
The city will monitor its water use through 2022 and will reconsider whether additional water
conservation goals are needed as part of the 2023 WEP update, which will also consider the
results of Boulder’s updated water supply reliability assessment and the city’s updated
demographic projections at that time.
Table 7-1: Boulder’s Near-Term Water Use Targets
Proposed Water Conservation Measures
Boulder’s proposed water conservation measures will be a continuation of Boulder’s existing
Water Conservation Program, which are tailored to meeting Boulder’s existing water
conservation goal and targets, and which have evolved to take advantage of partnerships with
other local and regional entities and to leverage the city’s water conservation funding. Boulder’s
existing Water Conservation Program will be continued (see Section 3 and details in Appendices
A and B).
Water Use Sector
Water use
target Units
Single Family 126 gallons per resident per day
Multi Family 57 gallons per resident per day
Commercial/Industrial 44 gallons per employee per day
Municipal 6.2 gallons per capita per day
Non-revenue water1 8.2%% of treated water production
Total Treated Water Demand2 19,336 acre-feet
1. Total annual treated water production minus total annual metered water use.
2. Year 2022 treated water demand; assumes average IWR.
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Continued Monitoring and Evaluation
Recommendations in the 2000 WCFS and 2011 WUMP all suggested that ongoing monitoring is
critical to helping evaluate Water Conservation Program effectiveness. Evaluation since that
time has shown that the Water Conservation Program is most effective when there is flexibility
to improve the program on an annual basis while meeting water use reduction targets and
Boulder’s other needs. For instance, switching from rebate based programs to service based
programs 2013 allowed for cost savings while providing several other benefits (as previously
discussed). Additionally, 2012-2013 Water Conservation Program planning demonstrated how
an adaptive program can collaborate with other city programs to develop a coordinated drought
response.
Adjustments to the Water Conservation Program will be based upon program analysis. This will
include monitoring of expenditures on water conservation activities, lessons learned, water uses
and local weather data, water losses, customer input, industry trends, regulatory changes and the
ability for program efforts to leverage other programs.
Coordination with Other City Initiatives
The Water Conservation Program has sought to maximize opportunities to enhance its
investments by partnering with city departments and outside organizations. For example, after
freeing up rebate dollars, the Water Conservation Program was able to leverage funds more
effectively by partnering with the city’s Climate and Sustainability Office to ensure that CII
assessments include both water and energy. Through a shared city contract with the County’s
PACE program, efforts not only incentivize efficiency upgrades but have led to direct install
programs for low-flow shower heads and pre-rinse spray valves that save both water and energy
without one program shouldering the full cost of that investment. Furthermore, these
partnerships have enhanced metrics and tracking through the annual PACE report.
Through the larger Watershed Sustainability and Outreach Program (see 6.1.3), the Water
Conservation Program has had greater access and ability to coordinate and develop various
cross-departmental efforts with Water Resources, Stormwater Quality, Flood, Drinking Water
and other city programs. It has also allowed the Water Conservation Program to link water
savings with larger resilience strategy and climate commitment efforts.
Coordination with Other Cities
The Water Conservation Program not only works with internal city departments but outside
municipal departments as well. These partnerships have resulted in successful, large projects that
can be equally shared amongst all partners while saving or using resources effectively.
The city’s outreach efforts through the Keep It Clean Partnership reach residents and business
across Boulder County. In partnership with Longmont, Lafayette, Louisville, Erie, Superior and
with Boulder County staff, the city has lead outreach efforts that have largely focused on
stormwater. However, in 2013 when drought concerns were prevalent, program efforts were
expanded to include water conservation. At the same time, the city worked to ensure that
stormwater runoff issues associated with E. coli and nutrients were added to existing water
conservation landscaping seminars in partner cities.
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In order to find new methods for outreach to students, the city partnered with Aurora Water and
Denver Water to develop a one-of-a-kind theatre production that focused on water conservation.
These three municipalities worked together alongside Metro State University and students from
the One World One Water center to develop a theatre production focused on messaging the value
of water for elementary students. This theatre production performed in eight different settings,
educating more than approximately 3,000 students and even won an award from the Colorado
Alliance for Environmental Education.
Seasonal Timing of Water Conservation Activities
Appendix C discusses how the seasonal timing of water conservation activities can influence the
benefits of saved water and has implications on Boulder Creek stream flows. The city should
explore further whether reductions in outdoor use during the runoff season, when Boulder is
exclusively using its direct flow rights and its reservoirs are full or expected to fill, would
provide any significant benefit. It may be advantageous to time the bulk of WCP outreach
efforts to coincide to the times of year when Boulder is not on direct flow. This could also help
maintain return flows to the stream in late summer and fall.
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8 Recommendations
To benefit the city’s future water conservation efforts, this study recommends that the city
continue to:
Have an Adaptive-Resilient Water Conservation Program- The Water
Conservation Program should be increasingly adaptive and resilient to new information (e.g.
demographics; climate; etc.) and changing conditions (e.g. wet and dry years). Projects that
produce this detail, like the BVCP and the climate change-based reliability assessment with
Water Resources, will offer data that can be used to refine Water Conservation Program
efforts. This information, along with other trends and measures of program effectiveness,
can then be used to determine if drought measures and water conservation goals need to be
reevaluated prior the 2023 WEP update.
Streamline Sustainability and Resilience Initiatives – Efforts to embed water conservation
planning into larger resilience, climate and energy planning should be pursued. This could
include energy mapping of water use, connections between water use and hydropower,
ongoing program efforts that save both water and energy as well better utilizing “resilience”
outreach as a means to talk about multiple hazards (e.g. drought, fire and flood). Continuing
to collaborate with Climate Commitment, Climate Modeling and Resilience Strategies should
be encouraged.
Advance Green Infrastructure Connections- City discussions around Green Infrastructure
and urban ecosystems highlight the importance of maintaining green spaces across the city.
The Water Conservation Program should continue to play an active role in these discussions
to help balance city water use and maximize the co-benefits of these initiatives (e.g. areas
where irrigation runoff can be reduced). The Water Conservation Program should explore
stakeholder engagement with other staff, master plans and community values regarding city
urban landscaping with their quality of life25. This will be important if Boulder considers
pursuing conservation efforts targeted at changing the existing urban landscape (i.e.
replacement of turf grass with xeriscape).
Evaluate City Metering, Customer Categorization and Water Loss- The Water
Conservation Program has a role in helping evaluate metering options, ensure that customers
are properly categorized and to limit water loss. As metering technology has improved, the
Water Conservation Program can help evaluate Advanced Metering Infrastructure (AMI),
options that would offer real-time meter reading, water use profiling, time of use billing,
demand forecasting and response feedback, flow monitoring and leak detection. Beyond the
immediate benefits of AMI, metering discussions may help identify opportunities to address
system and customer water loss, municipal water budgets and existing categorization
discrepancies between SF and MF customers.
25 The city of Fort Collins recently conducted a survey to assess their customer’s perspectiv e on the level of green
within their service area. Survey questions focused on perceptions of xeriscape vs. turf grass, the importance of turf
grass on public spaces and the importance of trees.
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9 References
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Aquacraft Water Engineering & Management, Headwaters Corp. 2011. SWSI 2010 Municipal
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Boulder County Consortium of Cities. 2013. Water Stewardship Task Force Final Report.
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International Energy Agency Statistics – 2012 Edition: CO2 Emissions from Fuel Combustion
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Water Resources Management and Adaptation. 2nd Edition, August 2014. A Report to the
Colorado Water Conservation Board.
Woodbury, Mark and Baldo, Marc (Riverside Technology, Inc.), Yates, David (National Center
for Atmospheric Research), Kaatz, Laurna (Denver Water). 2012. Joint Front Range Climate
Change Vulnerability Study.
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