The Colorado River Water Conservation District's (District) recent acquisition of the senior water rights associated with the Shoshone hydropower plant has raised concerns within Pitkin County. While widely considered a positive step for the Western Slope, officials are examining potential repercussions for the upper Roaring Fork River.
At the heart of the concern lies the interaction between the Shoshone water rights and the Cameo rights, a set of senior irrigation rights downstream in the Grand Valley. These rights interact with transmountain diversions in a way that directly impacts the Roaring Fork.
- Prior Appropriation: Colorado water law dictates that senior water rights receive priority ("first in time, first in right"). When a right isn't being fully satisfied, it can place a "call" on the river.
- Shoshone Call: A Shoshone call forces transmountain diverters (e.g., Denver Water) to curtail their diversions.
- Cameo Call: A Cameo call forces the Twin Lakes Reservoir and Canal Co. to stop diverting from the Roaring Fork headwaters, increasing flows downstream.
The Roaring Fork's Reliance on the Cameo Call
The Roaring Fork River's health, particularly in late summer and fall, benefits significantly from Cameo calls. Pitkin County worries that changes in the Shoshone right's use could alter river operations. This could lead to less frequent or delayed Cameo calls, extending Twin Lakes diversions and negatively impacting the upper Roaring Fork.
Pitkin County has engaged a water engineering firm to model the potential impacts. Key concerns include:
- Instream Flow: If the Colorado Water Conservation Board adds an instream flow component to the Shoshone right, it could change historical river operations.
- Value of the Deal: The $98 million price tag implies potential changes in how the right will be used.
The District acknowledges Pitkin County's concerns and is working to address them. Pitkin County aims to understand the full scope of potential impacts on the Roaring Fork, particularly during drought years. The county remains optimistic about working with the River District to find solutions that protect all interests.
To stay up to date on Shoshone water rights developments, visit the Colorado River Water Conservation District website.
