Agenda Date: 10/15/2019
Subject:
Title
Resolution 56-2019: Approving an Intergovernmental Agreement with Denver Water to allow construction of a storm drainage outlet into the High Line Canal at Windermere Street
Body
Prepared by:
Carolyn Roan, Water Resource Manager
PURPOSE:
To approve an Intergovernmental Agreement (IGA) with Denver Water to allow construction of a storm drainage outlet into the High Line Canal at Windermere Street and assume city maintenance of the canal corridor from this location downstream to the Lee Gulch waste gate.
PRESENTATIONS:
Staff Presenter(s): N/A
Additional Presenter(s): N/A
SUMMARY:
City council and staff have been involved in developing a regional vision for the future of the High Line Canal, part of which involves converting this irrigation feature into a stormwater feature. Historically, Denver Water has not permitted stormwater outfalls into the canal because of the potential contamination of irrigation water. However, the irrigation use of the canal is gradually ceasing to exist, and there is a movement to convert this canal into a stormwater collection and water quality treatment feature, which will maintain the vegetative community along the canal and its recreational value as the irrigation water flow decreases. This is documented in the Plan for the High Line Canal: New Life for a Regional Legacy, which was adopted by city council in Resolution 44-2019.
The City of Littleton has an opportunity, due to adjacent development, to contribute storm drainage into the canal at Windermere Street, and further the mission of the Plan for the High Line Canal. Currently, storm drainage from the residential area on the south side of the canal at this location is conveyed under and north of the canal via an inverted siphon pipe. By their very nature, inverted siphons create a maintenance issue because of stagnant water in the depressed portion of the pipe system during times of no flow or low flow because of insufficie...
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