Save the Colorado v. Semonite

On April 6, 2025, the court denied the Denver Water’s emergency motion to stay pending appeal both the April 3 preliminary injunction order and the underlying October 2024 order but granted a 14-day temporary stay of the preliminary injunction to allow Denver Water an opportunity to seek a stay from the Tenth Circuit.

On April 3, 2025, the federal district court for the District of Colorado concluded that remand with vacatur was the appropriate remedy for the U.S. Army Corps of Engineers’ violations of the Clean Water Act, the National Environmental Policy Act, and the Administrative Procedure Act when it issued a permit allowing the City and County of Denver’s Board of Water Commissioners (Denver Water) to expand the Gross Dam and Reservoir. The court found that an “amalgamation of … serious defects,” including a failure to quantify climate change’s effects on precipitation, supported vacatur as a remedy. The court also rejected the respondents’ and intervenor’s arguments that vacatur would not impact further construction because construction could proceed under a Federal Energy Regulatory Commission license and that remand with vacatur would cause environmental harm because the Corps permit gave it authority to enforce protective conditions. The court temporarily enjoined construction on the dam pending a hearing on a permanent construction injunction tailored to the amount of additional construction necessary to make the existing dam safe. The court permanently enjoined enlargement of the Gross Reservoir.

The federal district court for the District of Colorado ruled that the U.S. Army Corps of Engineers violated the Clean Water Act and the National Environmental Policy Act (NEPA) when the Corps issued a dredge-and-fill permit to the Denver municipal water entity for expansion of the Gross Dam and Reservoir. The court first addressed jurisdictional issues, finding that the petitioners had standing and that the case was not moot. Regarding the Clean Water Act, the court found that the administrative record did not disprove that alternatives that would not have required disturbance of wetlands were both practicable and available. The court also found that the Corps did not demonstrate that the project was the “least environmentally damaging practicable alternative” (LEDPA), including because the Corps ignored foreseeable effects of climate change on precipitation. The court wrote that “despite acknowledging that future climate conditions might neuter the Gross Dam’s value as a water storage solution, the Corps expressly declined to attempt to quantify the impacts of climate change—or even provide an educated guess, for purposes of discussion”—which the court said “proves fatal” to the LEDPA finding because “if the Gross Reservoir has no extra water to impound, or that water is lost to the sun or flora, the Proposed Action cannot possibly be practicable in a logistical sense.” Under NEPA, the court found that the Corp improperly merged “two conceptually distinct project purposes” and also failed to take a hard look at relevant issues, including climate change. The court said the Corps’ “refusal to provide even an estimate on future hydrology is indefensible, an abject violation of NEPA.” The court was not persuaded by the respondents’ contention that uncertainty justified the lack of consideration to climate impacts on precipitation. The court said that even if NEPA did not require quantification of such impacts, the Corps was “at least” obligated to “consider whether the practicability of a given alternative would change if the negative consequences identified in its qualitative analysis came to pass.” The court rejected a claim that the U.S. Fish and Wildlife Service violated the Endangered Species Act and deferred a final ruling on a specific remedy until after submission of further briefing.

The federal district court for the District of Colorado agreed with federal respondents that the Federal Power Act (FPA) required that petitioners’ challenges to U.S. Army Corps of Engineers and U.S. Fish and Wildlife Service (FWS) actions authorizing a dam project in Colorado be brought in a federal court of appeal. The district court noted that the FPA vests federal courts of appeal with exclusive jurisdiction to review not only the licensing orders of the Federal Energy Regulatory Commission (FERC) but also “all issues inhering in the controversy” related to a FERC order. In this case, the court found that the Corps, FERC, and FWS decisions were “inextricably intertwined.” The court therefore dismissed the case—which alleged, among other things, that the federal agencies failed to take into account climate change impacts and future climate change models—for lack of jurisdiction.

Environmental groups filed a lawsuit challenging the U.S. Army Corps of Engineers' authorization of the construction and operation of the tallest dam in Colorado history. They asserted that the Corps violated the National Environmental Policy Act (NEPA), the Clean Water Act, and the Endangered Species Act by, among other things, failing to take into account climate change impacts and future climate change models. The groups contended that the Corps violated NEPA by failing to "independently establish" that the project would achieve its stated purpose "in light of consensus-based projects of climate change." Under the Endangered Species Act, the groups asserted that the U.S. Fish and Wildlife Service had relied on outdated population estimates to quantify the take of cutthroat trout, including by failing to account for recent evidence of climate change.