The Elwha River is starting to flow free once again. The last pieces of the Elwha Dam, which blocked the river’s course for nearly a century, came down last year, and the upstream Glines Canyon Dam was supposed to be gone by autumn 2013 (though downstream issues now delay completion).
The river has already changed: Fish that were blocked by the dams have begun to recolonize the river’s upper reaches, mixing with populations that were trapped above them. Newly released water and sediments are transforming the riverbed and downstream beaches. This is a lab experiment on steroids, a largescale test of adaptation and evolution. Washington Sea Grant-funded researchers are taking advantage of this unique opportunity to learn how a river returns to a natural state.
Thomas Quinn, a professor in UW’s School of Aquatics and Fishery Science and a lead researcher on the Elwha project, is studying the changing life histories of the Elwha’s anadromous and resident fish populations. The river is home to all five native salmon species — Chinook, coho, sockeye, chum and pink — as well as Dolly Varden, steelhead, rainbow, bull, cutthroat, and nonnative brook trout. Before the dams, the Elwha’s salmon runs were among the biggest in the state; now only a few thousand fish return each year. But the river is primed for recolonization; 87 percent of its watershed lies within Olympic National Park, whose mossy trees and fog-shrouded hills are shielded from logging and mining. Quinn and other researchers hope to see dormant life cycles resume with the opening of the salmon’s ancestral habitat.
Just as the Chinook can now reach upstream habitat, Lake Sutherland’s formerly landlocked kokanee (freshwater sockeye) can now move downriver. Quinn wants to know if they were a pre-dam freshwater population or anadromous fish that got trapped behind the dams. To find out, he and his colleagues are measuring eggs and body shapes, sampling tissue isotopes, and removing otoliths (“ear stones” that show annual rings), all of which differ in anadromous and freshwater populations.
These questions aren’t just matters of curiosity, Quinn notes. They affect a population’s resilience and ability to adapt to changing conditions. If the ocean-going steelhead are flourishing while river-bound rainbows (freshwater versions of the same species) struggle, or vice versa, might one population stabilize the other?
This isn’t the first time Quinn has investigated salmon recolonization. When barriers to fish passage at the Landsburg Dam on the Cedar River came down in 2003, Quinn and other scientists measured and sampled the first salmon to venture upstream. But the Cedar pales in complexity; the Elwha is a much bigger river with many more species, and the dams’ removal will trigger a multitude of physical and biological changes. “On the Cedar, we essentially opened the door and kept count,” says Quinn. “On the Elwha, we kind of blew up the door… The removal of the huge dams will not leave convenient sites for counting fish, so keeping track of the recolonization will require many different kinds of studies.”
Historically the Elwha was home to stream-type Chinook, which are typically found in colder, larger and more stable river systems. Because of the low temperatures, stream-type Chinook are slow-growing and linger in freshwater for a year before migrating to sea. In contrast, ocean-type Chinook migrate after only a few months in freshwater. The Elwha’s headwaters were ideal for stream-type Chinook, but the dams blocked their way. Now these kings are returning and spawning — in very small numbers, NOAA fisheries biologist George Pess says, “but we’re starting to see it.”
The researchers are using a number of tools: sonar, which helps track fish in sediment-laden water; physical sampling to determine genetics, body morphology, and sex ratios; tagging to determine where the fish are spawning; and on-foot and snorkel surveys of juvenile fish.
Quinn is collaborating with researchers from a host of federal, state, and tribal entities, including NOAA, the U.S. Geological Survey, the Fish and Wildlife and National Parks Services, the Washington Department of Fish and Wildlife and the Lower Elwha Klallam Tribe. Collaboration is central to the project, he says, and necessary to avoid costly duplication. For example, Quinn asked tribal biologists, who were already measuring water quality and temperature on Lake Sutherland, to begin sampling zooplankton in the lake to determine whether returning salmon would have enough food. The tribe agreed, saving Quinn money and gaining information it could also use.
Student contributions are key to Sea Grant projects, and Emily Thornton, a fisheries graduate student at UW, has assisted with everything from sampling kokanee and zooplankton to snorkel surveys and invasive plant removal. She’s now trying to determine how long it takes steelhead fry to lose the saltwater isotopes transferred from their parents, to help identify fresh and saltwater fish in the Elwha. Lab fry will be fed ocean or freshwater food and the subsequent Elwha Unchained, Fish in Flux decline in nitrogen isotopes measured. “It’s trying to find the little ways the world works that haven’t been discovered before,” says Thornton. She’s also assessing how brook trout introduced after the dams’ construction will affect coho recolonization.
The dams’ removal has physical as well as biological implications. Preliminary estimates by the USGS suggest that the river has already flushed out nearly 1.2 million cubic meters of sediments. Sea Grant coastal hazards specialist Ian Miller is monitoring these sediments’ effects on the eroded beaches at the river’s mouth. Twice a month, Miller measures grain size and beach shape at three sites east of the mouth and one to the west. He uses kinematic differential GPS — basically the same system surveyors use — to compare today’s beach with measurements taken as far back as 2001. And he uses a USGS system called Cobble Cam to measure sand grain size from digital photos.
The changes are striking: The rocks of a year ago have been replaced by sand — a phenomenal amount, “unlike anything we’ve ever seen,” says Miller — and the once-eroding beach just east of the mouth has grown by nearly 100 meters.
Deciphering the Elwha’s changes requires both rapid response and long-term commitment. The Lower Elwha Klallam Tribe expects full restoration to take 20 to 30 years. That will consummate decades of work by the tribe, which helped win passage of the federal Elwha River Restoration Act in 1992.
“Getting the river restored has been one of the tribe’s top priorities ever since I can remember,” says Robert Elofson, who directs the tribe’s Elwha restoration projects. “When we started, just about our only allies were the environmental groups.” Eventually the federal agencies came on board, as the cost-benefit ratio for dam removal improved. Now the river itself, in its free-flowing natural state, is their ally.
Jocelyn Robinson 