Visit almost any city in the Kentucky River watershed after a rain and you’ll find water gushing through culverts, pouring out of storm sewers. The dark froth carries all the debris of modern life swept from lawns, parking lots and streets: fast food wrappers, plastic toys, tires. Less visible but equally present are pesticides and oil, fertilizers and human and animal waste. And it all winds up in the Kentucky River, which provides drinking water for more than 700,000 Kentuckians.
Of course, before we drink it the water goes through a treatment plant. But there are natural ways to clean the water too, and scientists and volunteers across Kentucky are working to restore those natural environments.
Ken Cooke is with Friends of Wolf Run, a group that’s adopted one of Lexington’s five urban streams. He describes the water’s path.
“Wolf Run starts up around Nicholasville Road in Lexington, it drains through Gardenside by Good Foods Co-Op, and then into Town Branch of South Elkhorn Creek and then it goes into Elkhorn proper and hits the Kentucky River about pool three, downstream of Frankfort.”
As Lexington became urbanized in the 20th century, the city’s meandering streams became a liability. They took up valuable space, and sometimes caused flooding. So engineers redirected them into underground pipes or straightened them out with concrete walls. It’s what Cooke calls “gray infrastructure,” but water find ways around those manmade barriers.
“When you take over from nature and you channelize a creek, or you concrete its banks you’re starting a battle that, unless you keep pouring energy and money and time into it you’re not going to win.”
But even if you keep up the battle, Alice Jones, a geography and geology professor at Eastern Kentucky University says that collecting and concentrating all that water speeds it up and that causes problems.
“It’s like putting finger over the end of a hose…you’re taking that same amount of water and you’re shooting it out with a lot more force.”
Jones has been recognized for her work on watershed management. She says increasing the water’s force erodes riverbanks, and moves the water so fast that dirt and pollutants don’t have time to settle out.
That’s one of the reasons Cooke and other volunteers across Kentucky believe it’s time to give up the gray infrastructure battle and focus on rebuilding the green infrastructure that once existed.
“Our approach is to make peace with nature and to engage nature to do the heavy lifting.”
The approach is simple but labor intensive: remove invasive non-native species like bush honeysuckle and plant grasses, flowers, bushes and trees. But it’s effective.
“One, is it absorbs water, takes it up and transpirates it through its leaves, it absorbs nutrients, pollutants, breaks down pollutants, and it shades the creek, shades water and keeps it cool.”
It also keeps dirt – the number one pollutant in Kentucky streams – out of the water by stabilizing the banks. Jones says that’s important because the aquatic plants essential to the ecosystem can’t grow if sun can’t filter through murky water.
“We’re basically cutting off the major source of energy to the stream, namely solar energy that is feeding the plants that then becomes the foodstuff for everything up the food chain.”
Trees are important because streams need some sun, but not too, much. Cool water, literally, gives fish some breathing room.
“Just like a hot coke won’t hold fizz, hot water won’t hold essential gases, like oxygen, that aquatic life needs to breathe, that fish need to breathe.”
And when stream banks are returned to natural vegetation and “no mow zones” are honored, the turn around can be as quick as one season. Scientists measure water quality but Cooke has his own way of telling when a stream is coming back to life.
“If I see dragonflies, to me that’s a sign of success. …They’re predatory insects, that means there’s stuff for them to eat, the water quality was clean enough long enough for them to mature and they are going to be our best bulwark against mosquitoes and other insects we don’t like.”
So, volunteers like the Friends of Wolf Run work yard by yard along Kentucky’s streams, trying to replace gray infrastructure with green, hoping to see the dragonflies return.
WEKU received assistance in producing this series of reports from Erica Peterson of Louisville Public Media.