Project Active

2014 – Present

Alamosa River – Terrace Reservoir

Terrace Reservoir Releases restore flows to the Alamosa River.

Through 2022, the Terrace Reservoir Project has restored over

billion gallons


of water to the Alamosa River.

How Did This Project Come to Us?:

The Alamosa River Watershed Restoration Master Plan and Environmental Assessment, created to support the river and the watershed after it had been affected by low flows and contamination, brought on Colorado Water Trust as a technical consultant for water rights and instream flow information in 2008. 

Tools Used:

Permanent Water Right Acquisition (Alamosa Riverkeeper used mitigation funding to purchase water rights diverted from the Alamosa River, and donated the water for permanent enrollment in the State’s Instream Flow Program. Every year, the water rights are stored in Terrace Reservoir and released to keep the river flowing in November, where it was historically dry prior to the project’s implementation.)

Project Partners:

Alamosa RIVERKEEPER, Colorado Water Conservation Board, Terrace Irrigation Company, Colorado Parks and Wildlife, URS Corp. (Project Consultant), Porzak Browning & Bushong LLP (Legal Assistance)

Project Years:

This project has restored flows to the river since 2015.

Project Story:

On November 5, 2015, the Division 3 water court issued final decrees to permanently bolster streamflow in the Alamosa River. These are the first water rights in the Alamosa River decreed for use by the Colorado Water Conservation Board (CWCB) for restoring streamflow. The water court’s official approvals for the new use of these water rights are the final steps in a multi-year process, spearheaded by Alamosa RIVERKEEPER® and the CWCB.

Alamosa River-Edalin Koziol

The Alamosa River, looking downstream

In addition to extending the season of flows in the Alamosa River, releases will supplement a 16-mile stretch of the river during periods of low flow to support the fishery and aquatic environment, improve riparian health, keep the streambed wet to limit loss of irrigation water, and recharge aquifers. The Colorado Water Trust has been associated with this project since 2008 as a technical consultant to Alamosa RIVERKEEPER® for water rights and instream flow information as they work to improve the water quality and the ecological functionality of the Alamosa River.

The Alamosa River and its watershed were contaminated by cyanide and toxic metals due to irresponsible mining practices at the Summitville mine, which eventually lead to a Comprehensive Environmental Response, Compensation and Liability Act, or Superfund, designation in 1992. Alamosa RIVERKEEPER® developed the Alamosa River Watershed Restoration Master Plan and Environmental Assessment (Master Plan) with comprehensive, broad objectives to restore the Alamosa River watershed. As part of this Master Plan, they purchased water rights in their watershed (2.5 cubic feet per second (cfs) of water from the Gabino Gallegos Ditch and 0.5 cfs in the Valdez Ditch) and then donated these water rights to the CWCB to enroll them in the state’s Instream Flow Program.


  • Photo Credit: Colorado Water Trust Staff
Use the flow dashboard below to learn about the operations of the Terrace Reservoir project, and just how much water has been restored to Alamosa River over the project’s lifetime. Just click or hover over the graphs below to learn more!

If you have trouble seeing the graphs below, click here