SACRAMENTO, Calif.— A federal judge in California ruled that federal approval of the Stonegate development, a 314-acre mixed-use project in Chico’s vernal pools, was unlawful.

Thursday’s U.S. District Court ruling said the U.S. Fish and Wildlife Service failed to address the potential harm from climate change on animals and plants that depend on vernal pools — seasonal wetlands that dot the landscape around the northern Sacramento River Valley.

“It was clear to us that federal agencies didn’t do their homework when allowing wetlands to be paved over. I’m pleased the court agreed,” said John Buse, senior counsel at the Center for Biological Diversity.

The court also ruled that the U.S. Army Corps of Engineers violated the Endangered Species Act by failing to consult with the U.S. Fish and Wildlife Service about how the project would harm the threatened giant garter snake. The residential and commercial development would destroy vernal pool habitat, which is home to not just the garter snake but vernal pool fairy shrimp, vernal pool tadpole shrimp and the endangered flower Butte County meadowfoam.

“The value of the habitat on Stonegate was documented for three decades by federal agencies and widely known by local residents and government. In this case, the court had to step in to remind all players of the values and the law,” said Barbara Vlamis, executive director of AquAlliance. “If we haphazardly build in these sensitive areas, we’ll wipe out the biodiversity that makes Butte County so special.”

In 2020 the Army Corps approved Stonegate on a site that had been identified by the Service as a core recovery area for vernal pool species. The area contains suitable habitat for the giant garter snake, but this fact wasn’t mentioned in the agencies’ review of the project.

In 2021 the Center and AquAlliance sued the federal agencies for approving the project and failing to protect endangered species habitat. Under Thursday’s ruling, the project cannot move forward until the agencies complete an adequate environmental review.