As more and more anadromous fish species have been added to the Endangered Species list, the removal of dams blocking salmon migration routes has been proposed. The first dams to receive a formal environmental impact analysis for removal are the Elwha and Glines dams on the Elwha River on the Olympic Peninsula in Washington. These 200-foot dams are very old and have no fish ladders. They block migration of fish to 70 miles of pristine spawning grounds in Olympic National Park, and it was estimated that their removal would more than triple salmon populations on the Elwha River. However, the cost to remove the dams and the 50 years of sediment build-up behind them was estimated to be in the neighborhood of $100-$125 million.