Agenda Date: 06/03/2025
Subject:
Title
Resolution 59-2025: Approving an Intergovernmental Agreement with Mile High Flood District regarding design and construction of drainage and flood control improvements for Rangeview Gulch from South Platte River to Prince Street
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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Sarah White, Water Resources Manager |
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Presentations: |
N/A |
PURPOSE:
Approval of an IGA with Mile High Flood District (MHFD) for design and construction of drainage and flood control improvements for Rangeview Gulch from South Platte River to Prince Street.
LONG-TERM OUTCOME(S) SERVED:
Safe Community; High Quality Governance; Sustainable Community with Natural Beauty
DISCUSSION:
Rangeview Gulch is a local floodplain within the City of Littleton. The floodplain forms north of the High Line Canal until its outfall at South Platte River. Rangeview Gulch passes through Ridgeview Park and is intercepted by the Englewood City Ditch. Rangeview Gulch then either overtops into Lee Gulch or over South Santa Fe Drive through the Meadowood Village Mobile Home Park.
The City of Littleton, in partnership with South Suburban Parks and Recreation District (SSPRD), are working on design alternatives for park improvements at Ridgeview Park, including the conversion into a regional detention basin as per the 2023 Integrated Water Resources Plan.
The City of Englewood is currently in process of piping City Ditch which alters the existing conveyance of Rangeview Gulch.
The City of Littleton, SSPRD, and MHFD, in conjunction with many grant funding partners, are constructing the Reynolds Landing Project near South Platte River. Reynolds Landing will have a floodplain terrace constructed for the eventual outfall of Rangeview Gulch.
With multiple projects occurring on the same floodplain within 1 mile of each other, it is prudent to look at these all as a complete project, to ensure one project does not create adverse impact on any other future projects and to ensure fiscal responsibility in completing overlapping projects with other funding partners.
The City of Littleton therefore desires to enter into contract with MHFD as a financial partner for the design and construction of the stormwater improvements from approximately Prince Street to the South Platte River.
BACKGROUND:
Ridgeview Park consists of the 0.7-acre Ridgeview Pond and a large area of turfgrass that is irrigated with potable water supplied by Denver Water. The park has historically been fed by seepage from the High Line Canal, overflow from private ponds upstream on the same drainage, and stormwater runoff. Declines in the volume of water run through the High Line Canal have decreased seepage into the pond. In 2023, the City of Littleton completed the Integrated Water Resources Plan which recommended the conversion of a pond at Ridgeview Park to a regional detention facility.
The City of Littleton and SSPRD have been working on conceptual design alternatives for this conversion. An open house and community outreach survey was conducted in August 2024. Conceptual designs were presented along with an engagement board to help determine what park amenities are desired by the community. The reconfiguration of the pond into a detention basin will require substantial infrastructure construction along South Curtice Street to ensure the Rangeview Gulch floodplain does not expand beyond its existing floodplain limits and ideally decrease those flooding limits to remove homes from the floodplain.
Rangeview Gulch is a combination of street conveyance and storm sewer from the outfall at Ridgeview Park down South Curtice Street to Englewood City Ditch. The City of Englewood is currently designing plans for the piping of City Ditch. City Ditch crosses Rangeview Gulch to the east of Sante Fe Dr and the Railroad, near a private pond known as Turtle Lake (aka Lynhardt Reservoir No. 2). Due to railroad conflicts, Englewood is unable to install their new water line in the railroad property and is proposing to use the existing easement alignment. As noted in the 1990 floodplain study “Flood Hazard Area Delineation Lower Dad Clark Gulch and DFA 0068” flows discharged from Turtle Lake historically went directly to South Platte River. However, due to the construction of the AT&SF Railroad embankment, these flows now go north along the east side of the railroad and discharge into Lee Gulch. The 1990 floodplain study “Outfall Systems Planning Lower Dad Clark Gulch and DFA 0068” provided recommendation for improvements to this crossing to get Rangeview Gulch to outfall at its historic location near Turtle Lake. Culverts have been installed under the railroad property and Santa Fe Drive This infrastructure was installed in 1997 but capped until a later date when financing was available. If capacity of the City Ditch is altered such that it no longer has capacity to convey low flows to Lee Gulch, it can cause adverse impacts to those homes adjacent to Turtle Lake and damage to the railroad embankment. It is proposed to work in conjunction with the Englewood piping project to connect the Rangeview Gulch flows to the installed culvert beneath the railroad west of Turtle Lake.
In 2014, the Breckenridge Brewery development granted a 40-foot drainage easement through the property for the future connection of the Railroad/Santa Fe culvert to the future planned outfall of Rangeview Gulch to the South Platte River at Reynolds Landing. Two additional 10-foot temporary construction easements were also granted for the construction of the drainage improvements (to be activated prior to construction).
Reynolds Landing Park is a 13-acre parcel along the South Platte River that currently includes an existing open space, the Superchi property (an abandoned house that the city acquired) and a stretch of ecologically degraded river. Littleton has partnered with Mile High Flood District, South Suburban Parks and Recreation and Arapahoe County since 2016 to begin transforming the space. In 2020, planning efforts began to restore the river. Through public engagement and expansion of partnerships, the project grew to incorporate the surrounding parkland and create a strong access to nature and serve as a gateway to the river. Phase I construction began January 2025. Later phase construction includes construction of a floodplain terrace for the eventual outfall of Rangeview Gulch.
Multiple projects are in various phases of design and construction. It is the intent of the City of Littleton to combine the design and construction of the remaining portions of Rangeview Gulch to complete the project in its entirety.
The City of Littleton desires to enter into an Intergovernmental Agreement with MHFD as a joint funding partner for the design and construction of the drainage improvements of Rangeview Gulch from Prince Street (Ridgeview Park) to South Platte River. The initial IGA is proposed for design with anticipated funds for construction to be added later. Capital Improvement Projects with MHFD require a minimum of 50% contribution from the local jurisdiction.
Prior Actions or Discussions
N/A
FISCAL IMPACTS:
Approval of this IGA authorizes not more than $300,000 be contributed by the city for design of the project. The city will be responsible for a minimum contribution of 50% of the project costs, with MHFD also contributing approximately 50% of the project cost. The total project cost is not finalized, and it is anticipated that funds for construction will be added to this agreement through future amendments. Staff will continue to search for additional funding sources as final design continues. $150,000 will be funded from the Storm Drainage Enterprise Fund, and $150,000 will be funded from the Open Space Fund.
STAFF RECOMMENDATION:
Staff recommends approval of the resolution approving the IGA.
ALTERNATIVES:
If not approved, the city would need to fund the project without the contribution from MHFD, and the project would be delayed until sufficient funds can be identified.
PROPOSED MOTION:
Proposed Motion
I move to approve Resolution 59-2025 approving an Intergovernmental Agreement with Mile High Flood District regarding design and construction of drainage and flood control improvements for Rangeview Gulch from South Platte River to Prince Street.