Agenda Date: 10/20/2026
Subject:
Title
Ketring Lake Water Management Strategies and Recommended Planning Direction
Body
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From: |
James L. Becklenberg, City Manager |
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Prepared by: |
Brent Soderlin, Director of Public Works & Utilities |
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Presentations: |
Brent Soderlin, Director of Public Works & Utilities |
PURPOSE:
The purpose of this presentation is to provide City Council with a high-level update on Ketring Lake conditions, historic context, drivers of water loss, existing water supply limitations, and key findings from Wright Water Engineers. Staff is seeking Council feedback on whether to advance wetland conversion and/or lake resizing for additional planning as the most sustainable long-term direction, while removing the option of maintaining the current lake size from further consideration unless a reliable water source is identified.
LONG-TERM OUTCOME(S) SERVED:
Sustainable Community with Natural Beauty
DISCUSSION:
Ketring Lake is experiencing a long-term imbalance between water demand and reliable available supply. The lake is approximately 11.2 acres in size and has historically served as an important community, recreational, visual, and ecological amenity within Ketring Park. However, the water sources and infrastructure that previously supported the lake are no longer sufficient to maintain the lake at its current size.
Current estimates indicate that maintaining the lake and related park uses requires approximately 76 acre-feet of water per year. The primary water loss drivers are evaporation, estimated at 29.1 acre-feet per year, and seepage through the aging lake liner, estimated at 26.7 acre-feet per year. Potential irrigation-related uses account for an additional 20.3 acre-feet per year. Together, evaporation and seepage represent the majority of the annual water demand and create a recurring deficit that existing water supplies cannot reliably replace.
Arapahoe Well #1, also referred to as the Ketring Well, is currently the only source available to support the lake. The well is permitted for up to 76 acre-feet per year with a maximum pumping rate of 200 gallons per minute; however, actual production is significantly lower than the permitted amount. For purposes of this discussion, staff is assuming the well is producing approximately 11 gallons per minute, which equates to roughly 17.7 acre-feet per year if operated continuously. This production level is well below the amount needed to maintain the existing lake and associated uses.
Wright Water Engineers reviewed available well records, testing information, borehole geophysical logs, and video inspection information for wells near Ketring Lake. Their key conclusion is that existing wells have significant yield, condition, permit, and/or ownership limitations and should not be considered dependable sources for major lake supply. For Arapahoe Well #1 (Ketring Well), the available information indicates significant drawdown and limited sustainable production. The Museum Well is limited by permit, historical use, ownership/access considerations, and condition. The Gallup Well (Library Well), completed in the Laramie-Fox Hills aquifer and now owned by Denver Water, has age, access, and water quality concerns. These findings indicate that the city should not rely on existing wells as a major supply solution for maintaining the current lake configuration.
Other potential water supply options also have significant constraints. Historic deliveries from the High Line Canal are no longer an option. Potable water is not considered a sustainable or available long-term lake-filling source and is constrained by Denver Water operating rules and the city’s service agreement. City Ditch water may be possible but would require substantial infrastructure, potential water court work, and coordination regarding legal and operational constraints. McLellan Reservoir water may provide a partial supply of up to approximately 16 acre-feet per year, but its use would require additional legal, operational, and infrastructure analysis and would not, by itself, close the supply gap.
Staff evaluated several broad options, including wetland conversion, lake resizing with a new or improved liner, construction of a new well, delivery of City Ditch water, use of McLellan Reservoir water, and maintaining the current lake size. Maintaining the existing 11.2-acre lake would require both liner replacement and a reliable additional water supply. At this time, staff has not identified a dependable and cost-effective source capable of supporting the current lake size over the long term.
Lower water demand alternatives appear to offer the strongest alignment between long-term water demand, available supply, sustainability goals, and potential grant funding opportunities. These alternatives include the wetland concept, a right-sized lake concept, or a hybrid approach that combines a smaller open water area with wetland, riparian, habitat, and shoreline restoration improvements. Each of these approaches would reduce the amount of open water requiring replacement supply, reduce long-term exposure to evaporation and seepage losses, and allow the site to be redesigned around verified sustainable water availability rather than the historic lake footprint.
A wetland concept would transition much of the existing lake area into wetland, riparian, and habitat features that require less supplemental water than the current lake. This approach would change the existing character of the lake, but it may provide the most resilient long-term condition under current water supply constraints. A wetland design could also support environmental education, wildlife habitat, water quality benefits, and potential grant opportunities tied to ecological restoration and open space values.
A right-sized lake concept would preserve a smaller permanent water feature while incorporating wetland edges, habitat areas, and shoreline restoration. This approach would maintain a recognizable lake element within Ketring Park, but at a scale that is better matched to available water supply. It would require capital investment for liner replacement or partial liner improvements, grading, shoreline stabilization, and related improvements.
A hybrid approach may ultimately provide the best balance between community expectations, visual character, ecological function, and long-term water sustainability. Under this approach, the city could evaluate a smaller lined pool or open water feature surrounded by expanded wetland and riparian areas. This would retain some of the visual and recreational benefits associated with Ketring Lake while substantially reducing annual water demand and improving habitat and shoreline conditions. The final configuration would need to be refined through additional planning, public input, engineering analysis, cost estimating, and confirmation of available water supplies.
Staff recommends removing “maintain current lake size” from further consideration unless and until a reliable water source is identified. Continuing to plan around the existing 11.2-acre lake footprint would likely require significant capital investment while leaving the city exposed to ongoing water supply uncertainty. By contrast, advancing lower water demand alternatives would allow the city to align the future of Ketring Lake with realistic water availability, sustainability goals, and potential outside funding opportunities.
Staff is seeking Council feedback on the following policy questions:
• Does Council support advancing lower water demand alternatives for additional planning, including a wetland conversion concept, a right-size the lake concept or a hybrid approach?
• Are there concerns with removing “maintain current lake size” from further consideration unless a reliable water source is identified?
• Does Council support staff pursuing grant opportunities beginning in 2027?
• What additional information would Council like before providing final direction?
Based on Council feedback, staff would begin pursuing planning and funding opportunities in 2027. Potential funding partners include Arapahoe County Open Spaces, South Suburban Parks and Recreation District, Great Outdoors Colorado, Denver Water, the City of Littleton, and private foundations. A potential project timeline could include grant applications and preliminary design in 2027, final design in 2028-2029, and construction funding and implementation beginning in 2029 or 2030, subject to Council direction, partner participation, grant awards, and future appropriations.
BACKGROUND:
Ketring Lake is a manmade reservoir located within Ketring Park. The lake is approximately 11.2 acres in size and has a storage capacity of approximately 98 acre-feet at normal high-water level. For many years, the lake has provided visual, recreational, and ecological value and has supported adjacent wetland areas and park-related irrigation needs.
Historically, the lake was supplied by water delivered from the High Line Canal through the Arbor Ditch. These deliveries helped maintain lake levels for many years. That supply is no longer available since Denver Water is no longer using the High Line Canal to convey contracted water to users along the canal, and the canal’s future through Littleton is focused on open space, conservation, stormwater, and water quality functions rather than routine water delivery. As a result, the historic source that supported Ketring Lake is no longer a reliable long-term supply.
In 2003, the city installed a PVC liner in Ketring Lake to reduce seepage. The liner has now reached or exceeded its expected useful life. Portions of the liner have been exposed along the shoreline, and recent seepage estimates indicate continued losses of approximately 26.7 acre-feet per year. This suggests that the liner is no longer effectively preventing water loss.
Following dry conditions in 2012, Denver Water provided a one-time potable water delivery to refill the lake using a temporary hydrant and hose system. Approximately 45.8 acre-feet of potable water was delivered at that time. That action addressed an immediate condition but was not intended to be a long-term operating strategy. Denver Water has since indicated that potable water cannot be used for this purpose due to operating rules, water supply conditions, and the prior one-time nature of the 2012 exception.
The city subsequently pursued groundwater as a non-potable water source for the lake. Arapahoe Well #1 was constructed in 2016 and is permitted for up to 76 acre-feet per year for municipal and irrigation purposes. Although the permitted volume theoretically aligns with the lake’s estimated annual demand, the well has not produced at that level. Staff is currently assuming a production rate of approximately 11 gallons per minute, or about 17.7 acre-feet per year. This is substantially less than the estimated 76 acre-feet per year needed to maintain the lake and related uses.
Multiple technical evaluations have been completed over time to better understand water demand, seepage, infrastructure needs, and supply options. These include prior feasibility work the Permontes Group, the 2023 Littleton Integrated Water Resources Plan, seepage evaluations, and the recent Wright Water Engineers review of well conditions and limitations.
The consistent conclusion from these efforts is that Ketring Lake’s current configuration requires more water than the city can reliably provide. Evaporation, seepage, aging infrastructure, limited well production, reduced surface water delivery options, and potable water restrictions have created an unsustainable operating condition. The city now needs to determine whether to continue pursuing options to maintain a permanent water feature or transition the site toward a lower-water wetland system that better matches available supply.
Prior Actions or Discussions
Staff have previously evaluated Ketring Lake’s water supply and infrastructure challenges through the Integrated Water Resources Plan (IWRP) and the Ketring/Gallup Master Plan. The IWRP was developed as part of Littleton’s long-range planning for water supply, demand forecasting, conservation, and drought management. The IWRP was approved by City Council during October 17, 2023, regular council meeting.
The Ketring/Gallup Master Plan was approved by City Council during the July 16, 2024, regular council meeting. The plan included an option to reduce the size of Ketring Lake.
FISCAL IMPACTS:
We have included $400K in the 2027 budget to start a planning effort in conjunction with South Suburban Parks and Recreation District.
STAFF RECOMMENDATION:
Staff recommends prioritizing wetland conversion and/or lake resizing since it is the most sustainable long-term option, while retaining lake resizing as a secondary alternative for further evaluation.
ALTERNATIVES:
Council may direct staff to pursue one or more alternatives to the staff recommendation:
1. Conduct additional analysis of supplemental water supplies before selecting a preferred direction. Staff could further evaluate City Ditch, McLellan Reservoir, stormwater capture, shallow groundwater, or other non-potable sources. This may provide more information but would delay design and grant applications, and these sources may still prove costly, legally constrained, or unreliable.
2. Evaluate a new groundwater source. A new well could potentially support a larger lake footprint, but yield, water quality, permitting, and long-term reliability are uncertain. This option would have high capital and operating costs and would likely still require liner replacement.
3. Maintain the existing lake footprint and replace the liner. This would preserve the current lake size and reduce seepage but would not resolve the overall water supply deficit. Existing well production is not sufficient to maintain the lake at its current size. This alternative would require a supplemental water supply.
4. Defer major capital action and continue current operations. This would avoid near-term capital costs but would not address the underlying water deficit, aging liner, or declining lake levels.
5. Conduct additional public outreach before selecting a preferred alternative. This would allow additional community and stakeholder input but may delay planning, design, and grant funding opportunities.
Proposed Motion