Environmental groups have filed a lawsuit trying to halt the building of a dam in the Del Puerto Canyon which would provide Valley farmers the water they need to grow crops.

A coalition of environmental groups sued the Del Puerto Water District last week for approving construction of a new dam on Del Puerto Creek.

The proposed Del Puerto Canyon Reservoir would store 82,000 acre-feet of water for downstream agricultural users. The coalition said the dam would flood an “important cultural and recreation site for the surrounding community and destroying valuable wildlife habitat.”

“The district’s plan to destroy this precious local landscape, and further strain the seriously imperiled Delta ecosystem, is sad and unfortunate,” said Sean Wirth of the Sierra Club. “This project would erase an important part of the area’s history and access to nearby nature, while also putting the residents of Patterson at risk should the dam fail.”

The environmentalists say the project would destroy 800 acres of habitat for red-legged frogs, tiger salamanders and golden eagles, protected species under California law, in addition to degrading downstream habitat in Del Puerto Creek.

“The water district’s environmental review didn’t even attempt to determine how many of these imperiled animals would be harmed by the project,” said Ross Middlemiss, a staff attorney with the Center for Biological Diversity. “Officials’ vague promises to look just before the bulldozers start won’t protect these iconic species from the project’s destruction.”

The reservoir would allow the district and its project partners to increase the amount of Delta water they’re able to receive under existing contracts, further straining the already over-taxed Delta ecosystem, the groups said. The reservoir would be filled via a new pipeline connected to the Delta Mendota Canal, a part of the federal Central Valley Project.

“Sucking more water from the Delta is not the solution to California’s water supply challenges,” said Ron Stork, senior policy advocate for Friends of the River. “This reservoir will only fuel increased demand among the agricultural interests of the San Joaquin Valley, worsening dependence on the already strained Delta.”

The project area is also home to populations of rare plant species that would be threatened by a new reservoir. Species such as the big tarplant, diamond-petaled California poppy and Lemmon’s jewelflower rely on the unique characteristics present in and around Del Puerto Canyon.

“Del Puerto Canyon is an important botanical and cultural resource,” said Nick Jensen, lead conservation scientist for the California Native Plant Society. “When a project’s analysis of impacts misses the crucial first step of information gathering – like here, where the plant surveys conducted were inconclusive at best – it renders the entire environmental review process meaningless. Californians and Del Puerto Canyon deserve better.”