The Downstream Reservoir Water Storage Program, which has been in the works since 1997, allows Denver Water to store and release water through the use of depleted gravel mines for exchange and replacement purposes.
Denver Water gets half of its water supply from the Colorado River. Because that water is not native to the Front Range, we have the ability to use and reuse that water multiple times, including storing it in the downstream reservoirs. Denver Water can then release that water when it’s needed downstream instead of releasing it from mountain storage. That helps keep water in the mountains while making the most of the water we have.
Denver Water has been reusing water by exchange since the early 1970s, but the Downstream Reservoir Water Storage Program is the first time Denver Water has put this reusable water directly into reservoirs.
There will be nine reservoirs divided into three complexes, which will have an estimated total storage volume of 32,200 acre-feet of water when construction is completed. The reservoirs are along the South Platte River, north of Denver, and extend from Commerce City to Fort Lupton.
South Reservoir Complex
Bambei-Walker and Welby reservoirs, near Commerce City, form the South Reservoir Complex and began operation in spring 2009.
North Reservoir Complex
Denver Water continues to work on its North Reservoir Complex, south of 120th Avenue and east of the South Platte River. There are five reservoirs in this complex, including Howe-Haller A, Howe-Haller B, Hazeltine, Dunes and Tanabe. Denver Water anticipates storing water in Dunes and Tanabe by gravity in spring 2018.
Mining has been completed in Howe-Haller A and Howe-Haller B. These reservoirs sustained damage during the floods in 2013 and 2015, but repairs have been completed so they may store water. Mining also has been completed at Hazeltine, but Denver Water is evaluating whether additional material should be removed to increase its storage capacity. These three reservoirs will be filled with water as demands require. All of the infrastructure, with the exception of a pump station and related electrical gear, have been constructed in the North Complex.
Lupton Lakes Complex
Denver Water also continues to move forward on its third complex. The Lupton Lakes Complex, in Fort Lupton, is expected to be operational sometime after 2030. Lupton Lakes consists of two reservoirs, the north and the south. Mining at the north has been completed and the liner has been installed; mining on the south continues.
Water level fluctuations
Typically, all of the reservoirs in the Downstream Reservoir Water Storage Program will be filled and drained on an annual basis. In general, these reservoirs will fill in the winter and drain in the summer, when downstream users — typically farmers — need water for irrigation.