Downing Reservoir Project

Downing Reservoir is Up and Running Again

Downing Reservoir Fall 2017

After more than two years, removing more than 340,000 tons of contaminated soil and doubling the size of the original reservoir, the Downing Reservoir Project is now complete.

The new reservoir has increased in size from 4.5 acres to its current size of 9 acres and can hold approximately 12 million gallons of water. The completion of this project allows the Denver Federal Center (DFC) to reclaim the water rights of the reservoir and use it for irrigating the landscaping. The Downing Reservoir decree established the water rights that have been part of the land since 1892 and were acquired with the purchase of the DFC property in January 1941. Water flowing from Clear Creek onto the property through an agricultural ditch can now be used to help reduce water utilities across the campus.

The reservoir is also designed to collect stormwater runoff from the DFC and stores it for up to 72 hours before being released into the nearby McIntyre Gulch. This feature is likely to help alleviate some of the flooding that occurs in McIntyre Gulch during severe thunderstorms.

The installation of a watertight synthetic liner under the reservoir prevents any potentially contaminated groundwater from coming in contact with the clean surface water flowing into the basin from Clear Creek. A groundwater treatment plant was also installed and is now operational to ensure any contaminated groundwater that does come into the reservoir has been treated to Environmental Protection Agency standards before use or if discharged into the nearby McIntyre Gulch.

The project removed soil contaminated with heavy metals resulting from industrial wastewater treatment operations when the property was used to manufacture ammunition during World War II and also from a historic landfill area near the western edge of the reservoir. At its peak, the project saw more than 200 trucks per day moving contaminated sediment and soil out of the area. More than 14,000 truckloads of soil were excavated from the site. This volume of traffic caused the area around Gate 2 to deteriorate, which had to be rebuilt. The gate was reopened on September 14, 2017 and repairs included new guard shacks.

“This project not only resolved an environmental issue on the Denver Federal Center, it also allows the government the opportunity to use our water rights to offset the potable water use on the DFC,” said Dana Coolbroth, project manager for the General Services Administration’s Rocky Mountain Region.

The area around the new reservoir will also be environmentally friendly by landscaping with a mix of plants and flowers that are drought-resistant and attract pollinators.

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