Elwha Ecosystem Restoration - History of The Elwha River

History of The Elwha River

Historically, the Elwha River was one of the few rivers in the contiguous United States that supported all of the anadromous salmonid species native to the Pacific Northwest. Ten stocks of anadromous salmon and trout species are known to have been present in the river before the dams were built: Spring- and summer/fall-run Chinook salmon Oncorhynchus tshawytscha, Chum salmon O. keta, Coho salmon O. kisutch, Pink salmon O. gorbuscha, Sockeye salmon O. nerka, summer- and winter-run steelhead trout O. mykiss, Bull trout Salvelinus confluentus, and Cutthroat trout O. clarki clarki. The river was considered the most prolific fish producer on the Olympic Peninsula. It was particularly known for its very large Chinook salmon, weighing as much as 45 kilograms (99 lb). Prior to the construction of the two dams on the river in the early 20th century, an estimated 392,000 fish returned annually to spawn. By the late 20th century the number had declined to less than 3,000.

Pink salmon were historically the most numerous salmon species in the river with over 250,000 adult returns. By the 1980s that number fell to near zero. Coho occupied the largest area of the watershed, going up many of the tributaries, and to nearly the headwaters of the Elwha River.

Salmon were an important food source for the Lower Elwha Klallam people who still live at the mouth of the river.

The salmon runs provided a valuable food source for many animals such as black bear, coyotes, gray wolves, bald eagles, raccoons, and dozens of others. In addition, salmon carcasses would litter stream banks during prime fall and spring spawning, providing food for scavengers and decaying. In the Elwha River basin salmon once contributed over 300 tons of phosphorus and nitrogen every year, via decaying carcasses and the scat of predators and scavengers. In this way salmon played an important role in the overall health of the ecosystem. About 130 species benefit from the nutrients in salmon carcasses.

Today, about 83% of the Elwha River's watershed lies within Olympic National Park, more than any other river on the Olympic Peninsula. Most of the Elwha's basin is in pristine condition, unlike many other rivers on the peninsula whose basins have been harmed by extensive land use, especially logging. Above the dams, the Elwha's basin remains largely in a natural condition. Limited development has occurred below the park boundary. Water is withdrawn for municipal and industrial use and there is some logging.