This summer, the U.S. Army Corps of Engineers and Washington Department of Ecology will battle an infestation of Eurasian watermilfoil, an invasive plant, in Rock Creek with an herbicide treatment. As part of a cooperative agreement with the Klickitat County Noxious Weed Board, contractors will treat the watermilfoil with an herbicide on two days between July 15 and August 31, and the Corps will temporarily close the recreation area.