Buffers Help Keep Big Darby Clean
The Big Darby Creek is one of the cleanest and most biologically diverse aquatic ecosystems of its size in the Midwest. It's home to several rare and endangered species In other parts of the region, agriculture, and rapid growth, have polluted natural waterways and made them less inviting to both wildlife and recreational users.
But a new Franklin County initiative to maintain buffer zones along the creek and its tributaries aims to help keep the Big Darby healthy.
In a few weeks, hundreds of acres next to Route 40 in Prairie Township will be filled with blooming native wildflowers. It's a stream buffer, a half-mile wide on either side, which the township and US department of Agriculture planted with natural vegetation a few years ago.
Environmentalists like Anthony Sasson of the Nature Conservancy hope hope the buffer will help improve water quality in the Hellbranch Run, a degraded tributary of the Big Darby Creek.
"This stream buffer right here is part of a multifaceted effort it's part f a puzzle we don't know exactly what will be needed to bring back Hellbranch Run -if that can be done but hopefully this is part of the effort that can slow down or even stop the degradation", said Sasson.
Buffers like this are one of the best ways to reduce the amount of pollution and sediment reaching the creek, and they have the benefit of being entirely natural. The forested land along streams are called riparian set-backs or stream buffers . By simply protecting and restoring the buffers the amount of pollution and sediment reaching the creek can be reduced.
"They basically serve as filters, large filters, that it would cost a huge amount of money to do it artificially if we had to create these things [these filters, so]. what we've got is a natural filtering system",said Sasson.
Rainwater enters a stream two ways either through groundwater or over the surface, in runoff. In both cases, the rainwater can pick up pollutants chemcials and fertilizer-from lawns, fields, and other surfaces. But when stream buffers are kept intact, the rainwater has a chance to permeate the soil so microbes and plant roots can remove some of the pollutants that would otherwise end up in the river. And with less rain flowing across the land surface, erosion becomes less of a problem, too.
Ohio State environment and natural resources professor William Mitsch says these riparian buffers are a major reason that the Big Darby Creek is so clean and healthy.
"If you go up and down the Darby, you'll see a lot of riparian zones already preserved. So there are tremendous areas where this is already happening. Had we farmed all the way to the edge of that stream like we do with many others, I don't think it would be in half as good shape as it is", said Mitsch.
In the 1970s, there were few restrictions on new construction in central Ohio. Some developers cared little about storm drainage and erosion along the state's waterways. The Nature Conservancy's Anthony Sasson says in areas upstream of the Big Darby, floods caused so much erosion that riverbanks reached up into homeowner's yards. "That is very obvious in a tributary that's upstream from here, that we call son of a ditch (laughs) It was to the point that their back patio was about to be eroded away", said Sasson.
But the fertilizers, chemicals, and erosion that often accompany development and agricultural activities can also harm the creek even when those activities are nowhere near the creek itself.
Sasson said,"Could be several miles, 5, 10 miles away, that you start an impact, and that just keeps building downstream . . .// Development anywhere in the watershed can affect Big Darby Creek ."
At their worst, these pollutants can kill off wildlife in the stream. Lawn and agricultural fertilizers can contain phosphorous and nitrogen. When phosphorous finds its way to streams or lakes, algae growth explodes, and ultimately sucks a lot of oxygen out of the water bad news for the fish.
"Basically the fish suffocate, they. . . or fish that need high levels of oxygen can't survive, and they're stressed."
And professor Mitsch, says what happens here in central Ohio can also affect wildlife hundreds of miles away.
Mitsch said, "Nitrogen is especially a problem, not so much, well, it's a problem up here for water quality in the Midwest, but it's also a problem when it gets into the Ohio basin and then down the Misss and causes what we call the hypoxia the dead zone in the Gulf of Mexico. It's a very serious pollution problem that's down in the Gulf of Mexico that's because of us up here."
Under a recommendation from the Federal EPA, The Franklin County Commissioners last month established stream buffer sones to help protect waterways throughout the Big Darby Creek watershed.
But buffers on Franklin County's little section of the Big Darby will only go so far in alleviating pollution downstream.
"We have to do it on a massive scale. We've called for the restoration of 5 million acres of wetlands and riparian zones in the Midwest to deal with that problem. So it's not a small effort that's need to solve that one", said Mitsch.
But Mitsch is cautiously optimistic that decisions like this one are becoming more widespread, He says governments and citizens are coming to appreciate the value of these natural stream-side areas.
"It seems like the rest of the world is recognizing that floodplains where the river goes sometimes, but not all the time, are just as important for a river as the river itself. We get in all sorts of trouble when we try to restrict our rivers and make them behave and stay in their channel all the time. They're not meant to."