Clean-up crews are racing to clear acres of debris at the largest Dakota Access protest camp before the spring thaw turns the snowy, trash-covered plains into an environmental disaster area. The U.S. Army Corps of Engineers announced Friday that the camp, located on federal land, would be closed Feb. 22 in order to “prevent injuries and significant environmental damage in the likely event of flooding in this area” at the mouth of the Cannonball River in North Dakota. “Without proper remediation, debris, trash, and untreated waste will wash into the Cannonball River and Lake Oahe,” the Corps said in its statement. Those involved in the clean-up effort, led by the Standing Rock Sioux, say it could take weeks for private sanitation companies and volunteers to clear the expanse of abandoned tents, teepees, sleeping bags, blankets, canned food, supplies and just plain garbage littering the Oceti Sakowin camp.