A Free Flowing River
EWU professor researches effects of the nation's largest dam removal on the Elwha River
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Rebecca Brown, Ph.D., has devoted her life to protecting and studying the watery areas of the nation. A professor and researcher at EWU, Brown specializes in riparian restoration and ecology. According to the Natural Resources and Conservation Service, riparian areas are the sections of land that occur along rivers and streams, including stream beds and floodplains. These areas are often partially or fully submerged for some of the year because of the natural flooding and flux around the borders of the water bodies they line.
Some researchers consider riparian zones to occur only at the edges of running water, while others have expanded the definition to include the land around lakes and ponds, Brown said during an interview with Spokane NPR in 2010.
Brown’s career in biology began at George Washington University in Washington, D.C. where she received an undergraduate degree in Environmental Science. After graduation, she worked for a year at American Rivers and then moved on to graduate school in North Carolina. There, she studied riparian vegetation in the Southern Appalachians.
Brown has a long history with kayaking, which she said eventually brought about her fascination with riparian ecosystems. As a biologist, she often uses kayaks to access her study sites, which allows her to study areas that are seldom — or never — observed.
After finishing her degree, she got the opportunity to work on dam removal on small dams with the Academy of Natural Sciences in Philadelphia.
“That led me to doing work on the Elwha. Around the same time I applied to a job position at Eastern and got that job position,” said Brown. “I love it [here]. I grew up around Baltimore, I spent time in Philadelphia. I like mountains and rivers and there’s lots of those here.”
At EWU, Brown teaches general biology, ecology, botany, research design, and literature and riparian ecology. Recently she was awarded a 2016-2017 Faculty Research Grant for her ongoing research monitoring vegetation changes after the dam removal on the Elwha River, located on the Olympic Peninsula.
The Elwha River flows from the Olympic mountains to the Strait of Juan de Fuca near Port Angeles. It had two large dams, the Glines Canyon dam and the Elwha dam. In 1992, the Elwha River Ecosystem and Fisheries Restoration Act was passed, allowing for the removal of the dams.
Though the dam removal was approved in 1992, the removal process did not actually begin until 2011. According to the National Park Service, the removal of the Elwha dam took place over six months and was followed several years later by the removal of the Glines Canyon dam.
The removal released around 22 million cubic yards of sediment into the lower and middle reaches of the river, Brown said, and though the release was done gradually, the impact of that much sediment, rushing downstream, was not insignificant.
“Usually we are trying to prevent sediment from going down rivers, and here we just [had] this huge amount going down,” said Brown. “All the beaches downstream had eroded and so the sediment is recharging those beaches. But, sending that much sediment down the lower river all at once has an impact. Since the dam removal there’s been these sort of transitory sediment packs. [The ecosystem] has to return to equilibrium before it can recover the plant species.”
According to an indirect quote of Brown’s in a 2014 National Geographic article detailing the removal, “the release of so much sediment in such a short time has created an ecosystem that’s distinctive and likely to stay that way.”
Before the dams were removed, there were about 45 percent fewer plant species downstream from the dams. Dams fragment a river’s ecosystem; they prevent seeds from flowing downstream and they change the structure of the river, which can prevent certain species from establishing themselves. Brown expects that once an equilibrium has been reached, the plant diversity in the lower and middle reaches of the Elwha river will gradually reestablish and the ecosystem will once again be as healthy as it was before the dams were built.
“[The Elwha river dams are] significant because it’s the largest dam removal that has ever been undertaken,” said Brown. “It is going to provide a lot of baseline research for other dam removals. In this country many of the dams were built in the ‘50s and ‘60s, and they have a designed life expectancy of about 50 years.”
This includes the Oroville dam, which was recently in the news after 18,000 people living near the dam were ordered to evacuate when a crater in the dam’s spillway, which had been discovered earlier in the year, had grown to dangerous proportions, according to an article in The Atlantic. At the time of the evacuation order, the crater had reached a depth of 45 feet and was 300 feet wide and 500 feet long.
According to the 2017 Infrastructure Report Card, thousands of the country’s dams are in serious need of renovation, lingering dangerously close to dozens of repeats of the Oroville incident.
“Right now, over half the dams in the country are older than their designed life expectancy,” said Brown. “[This] means that they have to go through a new permitting process to make sure they are safe.”
Fixing the dams and bringing them up to current safety levels is extremely expensive, and more and more, it is being decided that dam removal is the better option.
“Frequently what happens is that it is too expensive to maintain and continue to operate the dam, so they remove it, just because it’s old and not producing enough electricity or the ecological impacts are too high or it’s not safe,” Brown said.
Brown’s project is unique, not only because it studies the effects of the largest dam removal to be undertaken, but also because of the long term data it is producing.
“We came in many years before the dam removal and did vegetation surveys to evaluate the effects of the dam,” said Brown. “Since the dam removal, we’ve been doing surveys to monitor how things change after dam removal. We have plots we set up in 2005, resampled in 2010, and then resampled again in 2013, 2014 and 2016. We have several years of data in the same plots before and after dam removal that we can use to track how things change, which is really cool. Not too many studies have that.”