The future of Denver Water’s $531 million project to raise the height of the dam by 131 feet may be in question after a federal judge in Colorado found that the U.S. Army Corps of Engineers violated the Clean Water Act and the National Environmental Policy Act when it issued a dredge. – and fill out a permit for the work. But the judge deferred a final decision and is allowing construction to continue ahead of a planned winter break.
Denver Water is raising the dam from 340 feet to 471 feet to nearly triple the gross reservoir capacity from 42,000 acre-ft of water to 119,000 acre-ft. Utility officials say the project is needed to improve the system’s ability to meet growing demand and withstand drought, as well as to address an imbalance between Denver Water’s southern system, which provides 80 percent of its supply, and its northern system. , which includes the Gross Reservoir.
The expanded reservoir would affect 2.2 acres of wetlands and 3.5 acres of other waters of the United States. After the Corps of Engineers allowed it in 2017, environmental groups led by the nonprofit Save the Colorado filed a lawsuit in 2018, alleging the Corps had rejected alternatives without “clearly” showing that options were not available as required by US Environmental Protection Agency guidelines, and that the Corps had not been able to demonstrate that the selected option is the least environmentally harmful practicable alternative.
U.S. District Court Judge Christine Arguello in Denver wrote in an Oct. 16 order that she agreed with the groups, noting that the EPA had even informed the Corps in a 2003 comment about its notice of intent to prepare an environmental impact statement that the scope of the The project did not need to address both the need for more water and the imbalance between the north and south systems simultaneously, because that could cause the Corps to ignore alternatives that could solve them independently.
The order came after Arguello had previously dismissed the case in 2021 for lack of jurisdiction related to a Federal Energy Regulatory Commission (FERC) permit, but an appeals court overturned the decision .
“This is a stunning victory for the Colorado River, the people of Boulder County and the rule of law,” Gary Wockner of Save the Colorado said in a statement after Arguello’s latest order.
However, Arguello did not order a halt to construction, noting that interrupting concrete placement could compromise the structural integrity of the dam and that the reservoir has not yet contained additional water and the shoreline is remains unchanged for now. Work is expected to stop in November until spring. The judge ordered the parties to try to reach an agreement to resolve the issues before a briefing in mid-November.
Denver Water said in a statement that it is reviewing the judge’s decision and that it “remains focused on maintaining the safety and progress of the project.” The company stressed the project’s importance in helping secure water supplies for 1.5 million people against climate change, adding that it has a statutory FERC deadline to complete the project in 2027.
“It is critical that we continue construction on schedule to ensure the integrity and safety of both the current project configuration and the future dam and to meet the federally required completion deadline of [FERC]Denver Water said.
Representatives of the Omaha District of the Corps of Engineers, which issued the permit, did not immediately respond to inquiries.
Gross Dam was originally built in the 1950s. Expansion work began in 2022, led by a Kiewit-Barnard joint venture. As planned, the expanded dam would be the tallest in Colorado.
