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MSES Student Awarded Original Work Grant to Research Low-Head Dam Removal

Grace Cahill
April 20, 2018

As an Ohio University undergraduate studying geology, Brooke Stokes loved being outside and engaging in hands-on learning. Spending time in the field encouraged her love of science and exposed her to pressing regional issues like acid mine drainage. 

Now, as a candidate for a master of science in environmental studies, she’s tackling the problem of Ohio’s damaged streams head on.

“It was always in the back of my mind: How do you remediate these streams that we once thought were so far gone?” she said.

Stokes recently received an Original Work Grant, sponsored by Ohio University’s Graduate College and the Graduate Student Senate, to support her research into the feasibility of removing a low-head dam from Sandy Run, a tributary to Raccoon Creek that flows into Lake Hope. Her research is part of the conservation efforts of the Raccoon Creek Partnership, a nonprofit organization that was formed to improve and protect water quality in the Raccoon Creek Watershed.

A low-head dam is a small structure that holds back water to prevent floods; control human or livestock water supplies; or develop a stream for navigation, recreation, hydropower or irrigation. The small dams can block fish passage upstream, change habitat structures, and even slow the biological recovery of the watershed. 

Low-head dams aren’t just harmful to streams—they also pose a threat to public safety. “Unless you have firsthand knowledge, the dams don’t look dangerous,” said Stokes. But water just below the dams is dangerous because it circulates in a way that can trap animals, humans and other objects.

Stokes became interested in low-head dams when she learned that southeastern Ohio streams still struggle to recover despite successful efforts to remediate damage caused by generations of acid mine drainage. One reason is the presence of low-head dams that have altered many of the waterways, creating invisible problems that have gone unnoticed for years. 

“These streams have been impacted by acid mine drainage and heavy metals for so many years that we haven’t had the luxury to focus on other issues,” said Stokes. Those other issues—such as poor habitats and altered river flow—are less dramatic than the visually shocking orange water associated with acid mine drainage, but they’re no less serious. 

Before remediation, there were no fish or insects to save, Stokes said.  Now that creeks have returned to normal acidity, she said, it’s time to ensure the streams and their diverse inhabitants can thrive. 

Stokes is optimistic, but she doesn’t sugarcoat the situation. “There’s often a short-term hit because of the sedimentation built up behind the dam,” she says. Macroinvertebrates—aquatic insects and arthropods that can be seen with the naked eye—may suffer in the immediate aftermath, but this initial reaction will be followed by the long-term recovery of macroinvertebrate communities. 

Previous studies have revealed the long-term benefits of dam removal. “The natural flow regime is restored, the fish communities have been able to migrate and grow stronger—overall, there’s an overwhelming positive impact,” Stokes said. 

Stokes is taking measures to ensure that a possible dam removal on Sandy Run would do as little harm as possible. She has analyzed sediment from the dam to test for heavy metals and any negative impacts from the release of those sediments. Stokes submitted a nine-element plan—a strategic plan to improve water quality within a watershed—to the Ohio EPA and gained approval in March. 

Stokes hopes to remove the dam in the fall of 2018, during the stream’s low flow season. Raccoon Creek Partnership and the Voinovich School will be partnering with the Zaleski State Forest and Lake Hope State Park for the removal. 

“The dam is only 3.5 feet tall, but it has a pretty substantial impact,” Stokes said. “It’s blocking fish passage into upstream habitats.” One test Stokes cites found 12 species of fish downstream of the dam, and only four upstream of it. The dam had prevented the fish from traveling upstream to spawn. 

Stokes hopes that studying one dam removal project will give her concrete data and a method that will be easy to scale for future projects. A success story will also help to educate the public and allow dam removals in other streams. 

“It’s something that people don’t realize is an issue,” Stokes said. She’s done a few outreach events, including one at Rural Ohio Appalachia Revisited day, an annual celebration of Appalachian history and culture held at Lake Hope State Park. “Everywhere people have been very receptive to learning about the costs of the dams.”