When rainstorms dry up, local creeks do, too, leaving fish out of luck. A team of UC researchers and the Hamilton County Conservation District are testing out a relatively inexpensive solution to see if it helps make streams into successful wildlife habitats.
Flash flooding, stormwater runoff, and sewage overflows are big problems for urban creeks. Between rain events, these creeks often dry up, leaving no pools of water to support fish and wildlife.
Two UC biologists wondered if the problem might be solved using materials already available near the creeks — fallen logs and branches. Volunteers led by biologists Stephen Matter and Michael Booth, and Adam Lehmann, a stream specialist with the Hamilton County Conservation District, constructed strategic log jams along Cooper Creek in Blue Ash. The dams slow the flow of water during and after rain events, leaving behind pools of water for fish and wildlife.
"We had two basic objectives with the wood: one was creating habitat for fish during low flows... by creating scour pools associated with installing these wood structures, we can create a refuge for fish to survive in between rain events," Lehmann explains. "The other side of the urban hydrologic alteration coin is that we get these really, erosive flash flows at a much higher frequency — like every time it rains, we get these torrential flows (that) are just tearing up stream channels, and a lot of people are losing property over it. By restoring this wood, which is a natural component of undeveloped stream systems, we create a roughness element in the stream that will reduce the velocity of those flows, and hopefully reduce stream bank erosion."
Cooper Creek flows into the Mill Creek and then the Ohio River.
"Headwater streams are critical, both from the standpoint that they are diverse, unique ecosystems in themselves that ought to be conserved, but they're also important for maintaining the biological integrity of downstream rivers," Lehmann explains. "When you think about all the headwaters that have been piped from early development, and all the headwater stream miles that are going dry due to urban hydrologic alteration, it's a massive amount of habitat loss."
While Ohio is home to 170 native fish species, Booth says Cooper Creek only has about three.
"As we go downstream, we might add four or five more species," Booth says. "That’s a startling lack of biodiversity and a sign of an unhealthy ecosystem."
They're hoping by creating more habitats for fish upstream, more species will migrate upstream as well.
Lehmann says they could expect to find out if the logs and scour pools are working in about a year. The team is using LIDAR (a remote sensing technology) data and sampling fish, macroinvertebrates and salamanders in the stream to measure efficacy.
"What motivates me is local biodiversity and having that local wildlife in Hamilton County for the residents of Hamilton County to enjoy in the future," Lehmann says. "Right now, Cooper Creek, at least upper Cooper Creek, dries out so often that it's not just a degraded habitat, but it's a complete lost habitat from an aquatic perspective. Bringing that resource back for the local community to enjoy is what's really driven the project."
