The Downstream Reservoir Water Storage Project, which has been in the works for a decade, allows Denver Water to store and release reusable water in its system through the use of old gravel pits that have been improved to store water.
The gravel pits store water that is used for exchange purposes. In an exchange, other water is diverted upstream and the water in the reservoirs is released to meet water requirements of downstream users.
Denver Water has been reusing water by exchange since the early 1970s, but the Downstream Reservoir Water Storage Project is the first time Denver Water has put return flow into reservoirs directly.
There are three complexes in the project, which have an estimated total storage volume of 33,192 acre-feet of water. The reservoirs are all north of Denver, extending from Thornton past Brighton. Miller Reservoir and its neighbor to the west, Cat Reservoir, is part of the South Reservoir Complex and began operation in spring 2009.
Denver Water is now moving forward with 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.
To prepare those gravel pits for future water storage, Denver Water needs to construct infrastructure at the site. In 2010, Denver Water built the Fulton Inlet Pipeline to deliver water from the Fulton Ditch to fill the reservoirs in the North Complex. Crews also continue to mine Hazeltine Reservoir site and remove excess material to increase the reservoir’s storage capacity.
In 2011, Denver Water began buildng the outlet structure for Dunes Reservoir and a connection to the Fulton Inlet Pipeline so water can be moved in and out of Dunes. If all goes as planned, the North Complex reservoirs will be fully operational in 2019.
Denver Water also continues to move forward on its third complex. The Lupton Lakes complex, near Fort Lupton, is still being mined and is expected to begin operating sometime after 2020.
Turning gravel pits into reservoirs after they’re mined reclaims the land, provides new water storage and benefits the local environment. Now that Cat and Miller reservoirs are full, they provide habitat for waterfowl, raptors and other wildlife.