Reborn Olentangy becomes OSU lab
Like doctors on their daily rounds, members of a team of Ohio State University researchers are probing, testing and monitoring their patients — the Olentangy and Scioto rivers.
Dams have backed up the waterways’ natural flow for decades. And scientists know that these chokepoints adversely affect the rivers and their surrounding habitat.
Fish and sediment flow downstream, but they can’t flow back. Schools of fish and mussels are choked off, as are insects, which are food for many fish species. Even birds and mammals are forced to shift their behavior.
But the effects of dam removal are less clear. And two that came down last year — at 5th Avenue on the Olentangy near Ohio State and at Main Street on the Scioto near Downtown — are opening up new research opportunities.
“Understanding what happens when a dam comes down is not particularly well-resolved,” said Mazeika Sullivan, an assistant professor of aquatic-riparian ecology in the School of Environment and Natural Resources. “It’s a pretty new science.”
Across Ohio, there are more than 4,000 dams, with the vast majority being low-head dams. In recent years, however, some have been torn down. Four dams along the Olentangy in Delaware County were removed a few years ago.
Officials and wildlife experts said fish species — including the silver shiner, stonecat madtom, banded darter and brindled madtom — reappeared where one dam was removed in 2008. Even the endangered purple wartyback mussel was found downstream from where one dam had stood.
The 8-foot-high, 470-foot-wide dam at 5th Avenue was one of six low-head dams along the Olentangy in Franklin County. It was built in 1935 to provide water to cool Ohio State’s old power plant.
Sullivan is passionate about river restoration and said he knows that conservation extends well beyond riverbanks.
“If we can open up these systems, and that increases the diversity and abundance of these aquatic emerging insects that these terrestrial consumers are feeding on, then there’s actually potential conservation benefit,” he said. “So it’s not just about the river.”
Still, the science begins below water, where biological, chemical and physical changes occur.
“Although we know those changes are going to happen, we don’t necessarily understand the magnitude, the duration, the extent or the full picture of what those changes might be,” Sullivan said.
The study involves collecting data before and after a dam’s removal. And a control dam is needed to compare against.
Sullivan has studied the Dodridge dam, about 2 miles upstream from the 5th Avenue dam, for about three years, amassing data to compare with the newly altered downstream section of the Olentangy.
“We want to have a part of the system that hasn’t changed at all, one that still has an intact dam,” he said.
Near Ohio Stadium last week, researchers and graduate students plunged poles loaded with sensors into the river. The Olentangy has been radically transformed here since the dam came down in 2012, part of a $6.9 million project to restore the river and its banks between 5th and Lane avenues.
Kristin Jaeger, an assistant professor in the school of Environment and Natural Resources and co-leader of the study, was measuring the depth, temperature and flow speed.
“Right now, the velocity is 0.3 feet per second,” she said. Another probe collects data for chemical analyses.
On dry land, Jaeger’s car was filled with tubs of mud, gravel and sludge, hauled away for laboratory analysis. She also deployed a tool called an “acoustic Doppler profiler,” which maps the stream bed.
There are traps to collect insects, and birdhouses in which researchers can see whether swallows are finding their food on land or on the river.
Watching and listening, much like a good doctor, also are important.
“A big fish just jumped,” said Jaeger, as a leatherback turtle swam by and a killdeer squawked wildly, protecting her nest beneath a tree on the bank.
The study is important to those who aim to protect Columbus’ rivers.
“I am really curious to see the sorts of things they’re going to find,” said Alice Waldhauer, watershed coordinator for the advocacy group Friends of the Lower Olentangy Watershed. “The river has been more like a lake with the 5th Avenue dam.”
The Columbus study is funded by grants of more than $600,000 from the National Institutes for Water Resources, the Ohio Department of Natural Resources and the Ohio Water Development Authority.
“We’re hoping that the data collected on this project will help us estimate the impact of future dam removal in other parts of the state,” said Ken Heigel, chief engineer for the authority.
@DeanNarciso
