May 22, 2008
Surveys test effects of dam removal
In the run-up to river restoration following the planned dismantling of two hydroelectric dams on the Elwha River — the largest dams, by far, to be removed anywhere — scientists led by UW researchers have undertaken the complex task of documenting what’s in the river valley now.
Having that baseline is the only way to be able to measure the benefits — if any — to the ecosystem of having removed the dams.
“The Elwha project provides ideal conditions for testing hypotheses related to river restoration,” wrote Ted Pietsch in a project that has garnered $200,000 in start-up funds from the National Science Foundation to launch the survey. Pietsch, a professor of aquatic and fishery sciences and the principal investigator on the project, also wrote that this is a “unique opportunity to study the recovery of a riparian ecosystem, with profound implications for the value of dam removal elsewhere as a general conservation strategy.”
The dams are to be demolished starting in 2012. Congress has authorized $185 million for demolition, clean-up and to reintroduce salmon that have been shut out of the system since 1911 when the dams barred their migration.
With the $200,000 in research money from the National Science Foundation, work has begun collecting specimens along the river above, between and below the dams. The focus is on microorganisms, lichens, mosses, liverworts, fungi, spiders and insects — all taxa critical to other organisms being able to thrive in the area and the most vulnerable to change when the dams are removed.
Although only three hours by car and ferry from Seattle, the biota of the area is poorly known, Pietsch says. The survey and inventory project is bringing together professional taxonomists and an assemblage of agency, tribal, academic and citizen scientists.
Among the citizen scientists are school students from the area. In partnership with the Olympic Park Institute — a nonprofit that provides outdoor science education programs for students, teachers, and other citizens — monthly environmental education forays along the river got underway earlier this year.
There was an event for seventh and eighth graders and teachers of the Crescent School District in nearby Joyce, Wash. A similar event is scheduled for Native American students of the Lower Elwha Klallam Tribe in May and another in late June. There is funding to continue the outreach monthly throughout the summer and fall.
Dam removals are increasingly viewed as a means to restoring river ecosystems, especially in the Pacific Northwest where salmon stocks are seriously depleted and many rivers are closed to fish migration, Pietsch says.
The Elwha River has some advantages that other river systems do not. Because nearly all of the water above the dams is in the Olympic National Park, the ecological changes resulting from dam removal will be available for long-term study, without the confounding influences of human disturbance that are common in virtually all other river restoration projects.
“If dam removal is beneficial here, the knowledge gained can be applied anywhere; but if salmon restoration is less than successful under these ideal conditions, the implications for rivers elsewhere are dire,” he says.
