The U.S. Army Corps of Engineers is bullish on the idea of increasing water storage at Chatfield Reservoir, plunging ahead with a reallocation project that its planners believe will help meet future water needs across the metro area without diverting more supplies from the Western Slope. But a lawsuit filed this week by the Audubon Society of Greater Denver claims that the project will not only have a devastating impact on wildlife and recreation at Chatfield State Park but will fail to reliably provide additional water -- and that many of the water providers who initially backed the scheme have since dropped out.
As we reported back in 2012, the long-simmering proposal has set off alarm bells among environmentalists, bird fanciers and many park users because it involves flooding more than 500 acres of the 5,378-acre park and raising the water level by twelve feet. Critics say that will wipe out groves of cottonwood trees, destroy bird habitat, wetlands and walleye spawning areas, and leave an unsightly "bathtub ring" of barren mud flats around the reservoir when water levels are low. The lawsuit claims that the Corps improperly evaluated the project's impacts and dismissed a number of less damaging alternatives to the current plan.
Chatfield draws 1.6 million visitors a year and hosts 375 different species of birds -- fourteen of which are listed as protected by state or federal authorities. Audubon's attorneys contend that the project will cost the state around $3.4 million in lost park revenues, much of which is used to support less popular parks.
But the most intriguing claim in the suit has to do with whether the project will actually be of much use in boosting water storage for various agricultural and suburban interests. Several of the parties who initially signed on to the project, including the Parker Water and Sanitation District and the City of Brighton, have since dropped out and sought to meet water needs from other sources. Others, including the City of Aurora, "are trying to leave the project or have already left," the complaint states.
The reason for all those defections? While the project claims an estimated 8,539 acre‐feet of water per year as its average yield, the estimated "dependable yield" is zero. While the project has been presented as a "restoration" of the South Platte, the Corps' own studies predict that the river's flows would actually decrease nine months out of twelve after the project's completion and increase only one month of the year. Much of the water storage is allocated to junior rights holders and may be available only three years out of ten.
"It's a bad deal for the public and for Colorado," said Polly Reetz, conservation chairman of Denver Audubon, in an statement announcing the lawsuit.
But the Colorado Department of Natural Resources and the Colorado Water Conservation Board remain solid supporters of the project, and backers insist that the overall effect on Chatfield will be minimal. Denver Audubon and other environmental groups have said they would prefer to see more conservation measures and less drastic storage projects.
Read the entire complaint below.