Colorado’s largest water provider must stop construction on a $531 million dam expansion already underway in Boulder County after a federal judge found that assessments of how the project would impact the environment were flawed.
U.S. District Court Judge Christine Arguello in an order late Thursday blocked Denver Water from enlarging Gross Reservoir east of Nederland until major federal environmental permitting processes are redone.
The judge found that allowing the reservoir expansion to continue without redoing the permits would cause irreparable environmental damage that cannot be compensated for by monetary payments. That harm would outweigh any financial costs Denver Water would incur from halting construction, she wrote.
“Environmental injury is often the very definition of irreparable harm — often permanent or at least of long duration,” Arguello wrote. “All parties agree that there will be environmental harm resulting from completion of the Moffat Collection System Project, including the destruction of 500,000 trees, water diversion from several creeks, and impacts to wildlife by the sudden loss of land.”
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- In 2019, Denver7 took a 360 in-depth look at the expansion of a reservoir. Hear from multiple perspectives on its constructions in the video below.





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