#ColoradoRiver water banking discussion

Credit: Wikipedia.com

From The Grand Junction Daily Sentinel (Dennis Webb):

A public presentation related to an ongoing study might seem to envision a possible new, million-acre-foot reservoir not far upstream of Lake Powell in southeast Utah as a means of helping Powell’s water levels…

The presentation, which the consultant doing the study has been using to provide public updates on it, includes a map showing a triangle over what Wockner says is the Dirty Devil River near its confluence with the Colorado River. A label pointing to the triangle refers to a million-acre “Water Bank Reservoir.” But Kuhn, who is involved with the risk study, said the consultant, John Carron of Hydros Consulting, placed the reservoir there just for demonstration purposes.

Kuhn said the idea was to discuss storing that much water for banking purposes anywhere within the Upper Basin river system, from Powell itself to upstream reservoirs. That storage could include newly created storage, he said, but any new storage would likely have to overcome the challenge of cost-competitiveness versus using existing storage space, not to mention considerations such as environmental impacts and political viability.

The water-banking concept — discussed again Wednesday in a meeting in Grand Junction of representatives of stakeholder groups for West Slope basins of the Colorado River watershed — would entail conserving water through temporary irrigation fallowing and other means and then storing that water to help shore up Powell levels. Water officials are concerned that continuing drought could drop those levels low enough that it could jeopardize hydropower generation and the ability of Upper-Basin states to meet legal obligations to deliver water downstream.

Powell itself, with its huge size and current large amount of unused storage space, is an obvious and convenient place to consider banking water, according to Kuhn and other water officials. The Bureau of Reclamation reports that as of the end of March, it had about 13 million acre-feet of water in it, and was about 53 percent full. Many upstream reservoirs are less well-positioned to bank water for the long term because they’re designed to fill in wet years.

However, the challenge when it comes to Powell is how to figure out how to ensure any water that’s banked there can actually go toward helping protect the reservoir’s levels rather than being subject to release downstream based on other agreements dictating operations of Powell as part of the larger Colorado River system.

But Kuhn says there’s a precedent for what’s called intentionally created storage or surplus already in place in the Lower Basin, taking advantage of vacant storage space in Lake Mead.

“It’s more than just a conceptual idea. It actually works,” said Kuhn, who said that shows the concept can work elsewhere in the Colorado River Basin.

If new storage is considered, one possibility that could be evaluated is in far northwest Colorado. The Rio Blanco Water Conservancy District in Rangely has been looking at a possible storage project at Wolf Creek, a tributary to the White River on the Moffat County line. Kuhn said that reservoir could be built for local needs in Rio Blanco County, but also sized up to help bank water for Powell. But he said it wouldn’t provide enough space, nor is the White River big enough, for such a reservoir to meet the entire water bank needs.

Rather, storage for a bank could be spread out among multiple reservoirs.

Kuhn believes new storage can’t be ruled out as a possibility.

“I think the (Upper) Basin has to be open to all suggestions and then weed them out,” he said.

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