Columbia Riverkeeper on Wednesday filed a set of lawsuits targeting the U.S. Army Corps of Engineers for what it calls illegal discharges of oil and pollutants from eight dams on the Columbia and Snake rivers.In complaints filed in U.S. District Courts in Portland, Tacoma and Eastern Washington, the Oregon-based advocacy group described a series of leaks and discharges it argues are in violation of the federal Clean Water Act. The facilities under scrutiny are Bonneville Dam, The Dalles Dam, John Day Dam and McNary Dam on the Columbia, and Ice Harbor Dam, Lower Monumental Dam, Little Goose Dam and Lower Granite Dam on the Snake. Each complaint focuses on different dams, depending on each court’s jurisdiction.The complaints list the U.S. Army Corps of Engineers, which operates the facilities, and Lieutenant General Thomas Bostick as defendants.It wasn’t any one incident that prompted Columbia Riverkeeper to file a lawsuit against the Army Corps over dam pollution, said executive director Brett VandenHeuvel. It was an accumulation of incidents showing a persistent problem that must be addressed, he said.“We’ve been investigating dam oil spills for several years,” VandenHeuvel said. “It continues to be a problem, and now is the time to take action.”The Army Corps is reviewing the complaints, said spokeswoman Amy Echols. The agency doesn’t comment on ongoing litigation, she said.Oil leaks aren’t uncommon in the Columbia and Snake river system, home to numerous aging federal dams. The complicated, decades-old structures include many components that require oil to keep them running.