Pres. Clinton gave federal protection on Friday to the area around the last free-flowing stretch of the Columbia River, called the Hanford Reach, a move aimed at helping recovery of the Pacific salmon. Some 57,000 acres of land along the 47-mile stretch of river will be added to a national wildlife refuge in southern Washington state. The land has remained relatively pristine, ironically, because it has been part of a security buffer for the Hanford nuclear reservation, the most contaminated nuclear site in the nation. The area is home to more than 200 species of birds and more than 40 rare plants and animals. Clinton made the move because Congress has refused to designate the stretch as a Wild and Scenic River.