The Newhall Ranch development hit yet another snag this week as environmentalists filed a federal lawsuit to halt construction. The Santa Clarita Organization for Planning the Environment (Scope) and several other environmental groups filed the suit on Thursday in Los Angeles federal court. The suit names the U.S. Army Corps of Engineers and the U.S. Environmental Protection Agency as defendants, claiming permits the groups provided in 2011 for the sprawling project weren’t warranted. Newhall Land & Farming Co., the developer of Valencia, is seeking to build 20,000 residences and 5 million square feet of office space over more than 2,500 acres. The project could take 30 years to come to fruition. “Rather than ensuring that the last free-flowing river in the county is preserved, the agencies have approved development directly in the Santa Clara River’s fragile floodplain,” said Scope President Lynne Plambeck, in a statement. “It is time to implement new planning concepts that protect, not destroy, wildlife habitat, water resources and our local agriculture.” Marlee Lauffer, spokeswoman for Newhall Land, said the company has been sued 22 times regarding the Valencia and Newhall Ranch developments. “We have not reviewed the suit yet, however we spent over a decade working with Army Corps and other federal and state agencies analyzing and reviewing all of the environmental issues,” she said in an email. “The result is permits that further protect significant open space and resource areas, adds extensive mitigation to the plan and provides over $10 million dollars for an endowment.” Newhall Ranch, first conceived in the 1980s, has been consistently opposed by environmental groups, who have been successful in at least delaying the development. Prior to the latest litigation, the groups filed suit against the California Department of Fish and Wildlife for signing off on the development. An L.A. Superior Court judge ruled against the developer in 2012, but the case immediately was appealed and a judgment is expected soon.