The Environmental Council of Sacramento and the Sierra Club have sued Sacramento County over its approval of the Cordova Hills development on the eastern edge of the county.
Environmentalists complain that the project is a continuation of suburban development that leads to more driving and pollution. They also worry about the loss of vernal pools, seasonal wetlands that provide habitat for protected species such as shrimp.
"This project is classic leapfrog sprawl development," said Sean Wirth, conservation chair for the Mother Lode Chapter of the Sierra Club, in a news release.
In late January, county supervisors approved the 2,700-acre development, which calls for up to 8,000 housing units and commercial development off Grant Line Road next to Rancho Cordova.
Developer Ron Alvarado defended the project.
"Cordova Hills has been collaboratively planned under some of the most stringent, substantial and environmentally sensitive criteria ever seen for a land-use plan in the region," he said.
In the lawsuit filed Friday in Superior Court, environmentalists accuse the county of violating the California Environmental Quality Act. They ask the court to set aside the county's environmental impact report and overturn its approval of the project.
The county's environmental impact report failed to take into account that the developer has not secured a university for the project, which means residents of the new development will drive more to reach employment and create more pollution, the lawsuit claims.
The impact report wrongly makes the assumption that the university will offset pollution that would otherwise be expected, according to the lawsuit.
"The premise of the application is that this project is justifiable, regardless of location, because it has a feature that helps reduce the impact," said Rob Burness of the Environmental Council of Sacramento. "When the university disappeared, that argument went away."
County supervisors approved the project even after the head of the Sacramento Area Council of Governments told them it could push the region out of compliance with Senate Bill 375, a state law that aims to reduce greenhouse gas emissions through land-use and transportation planning.
County spokeswoman Chris Andis said the county would not comment because it has yet to see the petition.
In the past, county officials have pointed to the developer's agreement to commit time and money to try to attract a university to the project, and to give the county land set aside for the university if he is not able to find a school for the site.
County officials have also defended the project by saying that it will contain a number of environmentally sensitive features, such as a shuttle service. Call The Bee's Brad Branan, (916) 321-1065. Follow him on Twitter @bradb_at_sacbee.