A federal judge ruled late Thursday that Denver Water can continue construction to raise the height of Gross Dam but cannot fill the expanded reservoir once the dam is complete. U.S. District Judge Christine Arguello’s decision aims to prevent the risk of a catastrophic dam failure and protect habitat and lives downstream.
The ruling comes after years of environmental groups’ efforts to stop the expansion of Gross Reservoir, which Denver Water plans to triple in size to increase water storage and create a more resilient water delivery system. Despite opposition due to environmental concerns, construction on the project began in 2022 and was 60% complete by early May.
Arguello’s decision follows a 10-hour hearing where experts from Denver Water and environmental groups presented arguments. While Denver Water’s experts warned of increased risks with a pause in construction, the environmental groups’ expert suggested little risk of failure if construction were delayed for redesign.
While the judge found flaws in the permitting process, she did not find evidence that halting construction would cause further environmental harm. However, Denver Water is still prohibited from filling the reservoir to its new capacity once the dam is complete.
Save the Colorado’s executive director, Gary Wockner, expressed respect for the judge’s concern about public safety and highlighted the continued legal battle over the project. Denver Water has appealed the ruling on the permitting process violation and plans to pursue the case further.
Denver Water stated that completing construction on the current timeline mandated by the Federal Energy Regulatory Commission is the safest path forward, as emphasized by the judge’s order. The utility remains committed to the project despite the legal challenges.
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