Two environmental groups have sued Placer County over its approval last month of Placer Vineyards, a 14,132-home development expected to bring about 33,000 new residents west of Roseville.

The groups - Mother Lode Chapter Sierra Club and Sierra Foothills Audubon Society - allege in the suit filed in Placer Superior Court that the Board of Supervisors failed to require developers to provide sufficient vernal pool grasslands in violation of state and federal environmental laws.

"We need growth that is more compact if we are to save some of the county's remaining habitat and farmland," the Sierra Club's Terry Davis said in a news release.

He accused the county of approving "more of the same old sprawl" instead of following a regional growth blueprint or a pending conservation plan that he said would have made for better planning.

Bruce Kranz, chairman of the Board of Supervisors, said the lawsuit was not unexpected since Davis had threatened litigation at the last two public hearings on the Placer Vineyards project.

Kranz said he is confident that the board's approval of the project and the environmental documents will survive a court challenge.

"Vernal pools were addressed, as were climate change, roads, water, everything," he said. "It was one of the most studied plans that's ever been seen in our county."