The Elwha River, which runs through the heart of Olympic National Park on Washington State’s Olympic Peninsula, was once the spawning ground for hundreds of thousands of steelhead and salmon. It was also a productive traditional fishing area for the Native American Klallam Tribe. Things changed when two large dams were constructed on the river in the early part of the 20th Century without any provision for fish passage. For nearly a century, the dams have prevented native salmon and steelhead from reaching pristine habitat within the National Park. Populations have declined so greatly that only a few thousand now return to the accessible five-mile reach between the Strait of Juan de Fuca and the lowest dam. Since 1992, the National Park Service and U.S. Bureau of Reclamation have been working on a plan for decommissioning and removing the dams. Work finally commenced last September, and full removal is anticipated before the end of next year. The project represents the largest dam removal in history and is also one of the largest ecosystem restoration projects ever attempted.
Two teams of Seattle University students have had the opportunity to be a part of this historic project. The first team, consisting of SU Civil and Environmental engineering students Kevin Cook, Justin Milne, Kristin Pesman, Katrina Schwab, and Jim Shannon, has assisted the Bureau of Reclamation with hydraulic analysis focused on how deconstruction influences flow releases from the two reservoirs. They will present their work at national engineering conferences sponsored by the American Society of Civil Engineers and the Association of State Dam Safety Officials. The second team, consisting of CEE students Mark Beggs, Marshall Kosaka, Anna Sigel, and Renee Vandermause, has focused on monitoring downstream impacts. “There is a century’s worth of sediment behind the dam that is released into the river as the dam is deconstructed,” says Renee Vandermause. “Our team is analyzing the affects of sediment pulses on how the river flows.” “The goal is to create a predictive baseline that may help future deconstruction projects to learn about the hydraulic effects of sediment redistribution and how this affects the long term recovery of the ecosystem,” adds Marshall Kosaka. The team anticipates presenting its results at an upcoming Elwha Science Symposium. The results of both projects can be seen in full at the upcoming Projects Day on May 30th from 1-5:30 at Sullivan Hall, SU Law School.