Judges permit Denver to divert 77,000 acre feet from the Colorado River for reservoir expansion

Denver Water’s expansion of the Gross Reservoir can continue after three judges ruled in favor of the project after a challenge from environmental group Save the Colorado. The organization sued the U.S. Army Corps of Engineers and Denver Water over the planned expansion, alleging that the organizations did not adequately consider the impact expanding the dam — and diverting an additional 77,000 acre feet from the Colorado River — would have on the already-stressed body of water.

A spokesperson from Denver Water provided Inside Climate News a statement regarding the judges’ decision:

“An expanded Gross Reservoir is vital to the future of the Denver region, giving Denver Water far greater ability to flexibly manage constrained water supplies amid the growing risks of catastrophic wildfire and weather extremes that accompany the challenges of drought and climate change already upon us.”

The Colorado River supplies 40 million people across seven Western states and Mexico with water. Climate change and overuse have caused the river’s water levels to plummet in recent years, Jake Bolster and Wyatt Myskow write for Inside Climate News. Denver Water expects to finish expanding the dam in 2028, and previously told Inside Climate News it would fill the new reservoir in stages, pulling from the Colorado River only in wet years.