Columbia Riverkeeper is suing the U.S. Army Corps of Engineers, claiming it is illegally polluting the Columbia River with hot water, oil, and toxic chemicals.  The organization says four dams operated by the Corps on the Columbia River between Portland and the Tri-Cities discharge illegal pollution in violation of the Clean Water Act, claiming in the suit filed in federal court that pollutants continued to be discharged, including heated cooling water and oils and greases, from The Dalles Dam, John Day Dam, and McNary Dam without obtaining required permits.  The suit also says in 2014 the two parties settled litigation by giving the Corps seven years to apply for those permits and take other action.  In response, the Corps says it applied for the permits in 2015, and continues to work to balance all of the purposes of the Columbia River system.  The Corps also says although the pools behind Lower Columbia River dams are considered reservoirs, they are not storage reservoirs, but rather run-of-river facilities, limiting the ability to impact water temperatures by drawing down water levels in the spring.