In a landmark decision for Colorado water policy, the Colorado Water Conservation Board (CWCB) voted unanimously last week to approve the acquisition of the Shoshone water rights, a move that promises to permanently protect flows through Glenwood Canyon and downstream ecosystems. 

The vote authorizes the CWCB to designate the historic Shoshone rights for instream flow use, while the Colorado River District retains ownership. This partnership ensures the rights are used to keep water in the river for environmental benefit rather than diversion for municipal or agricultural use. Once finalized, this will establish one of the largest environmental water rights in Colorado history. 

At the center of the agreement is the Shoshone Hydroelectric Power Plant in Glenwood Canyon. The plant holds senior water rights dating back to 1905, commanding a flow of 1,250 cubic feet per second. Because these rights are so old, they are senior to most other users on the river, meaning the plant can demand water be sent downstream even when the river is low, bypassing junior users upstream. 

For decades, the “Shoshone Call” has effectively kept the Colorado River healthy by forcing water through the state’s Western Slope, benefiting local agriculture, recreation, and endangered fish species. 

The Colorado River Water Conservation District, representing Western Slope interests, struck a deal earlier this year to purchase the rights from Xcel Energy for $99 million. Under the plan approved by the CWCB, the River District and the state board will co-manage the rights for instream flow purposes. 

“This is a legacy moment for the Colorado River,” proponents of the deal argued, noting that securing the flows permanently protects the river against future development or changes in energy production that could have otherwise left the riverbed dry. Governor Jared Polis hailed the decision as a generational win for Colorado’s wildlife, communities, and water security. 

However, the decision was not without controversy. Major Front Range water providers, including utilities serving the Denver metro area, expressed significant concerns during the proceedings. Representatives for these utilities asked the board to include “off-ramps” or specific drought protections that would allow upstream cities to divert more water during extreme emergencies. 

The CWCB ultimately declined to add those specific conditions to the current agreement, opting to move forward with the acquisition as proposed. 

The process now moves to Colorado’s water court. The state and the River District must file an application to legally change the water rights to include instream flow as a designated use. This legal phase is expected to be complex and could face formal opposition from Front Range providers who remain concerned about long-term water supply flexibility. 

Despite the hurdles ahead, the board’s vote marks a pivotal shift in western water law, prioritizing river health and stability for the Western Slope in an era of increasing aridity.