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Fri March 23, 2012
Obion Creek: Fixing Nature That's Been Tinkered With
The Earth’s ecosystems operate on a fragile balance between soil, water and wildlife. In the early 20th century, a local drainage district upset this balance when it straightened and widened a Hickman County stream. It hoped to drain the land to add farmable soil to the area, but the stream clogged and farmers wound up with more water instead of less.
The Obion Creek flows under a Highway 307 bridge in Hickman County. It’s murky waters rush underneath the pilings, as quaintly named fish like the Bluntface Shiner, the Lake Chubsucker and the Chain Pickerel swim through the khaki-colored stream. But for several decades, the Obion stood still, covering the creek’s adjacent floodplain and killing surrounding hardwood trees.
People had tinkered with the environment. So says Arthur Parola a professor from U of L’s Stream Institute. “In the 1920s, they channelized the stream, which means that they came in with these large barges that they dug in somewhere maybe 20 miles away from here, and they started dredging a straight channel that maybe curved a little bit to follow the valley and constructed a channel that was somewhere in the neighborhood of 70 feet wide by 10 feet deep," said Parola.
Working with state money outside the general fund, Parola oversees efforts to restore the Obion to its original condition. He says the channelization had backfired. “Once you straighten those channels, they start to erode. (the banks) started to widen and increased the sediment supply to this main Obion Creek by perhaps 100 to 1000 fold,” said Parola
Parola says the drainage district began the channelization in an honest effort to boost the local economy, but the banks and beds of the channelized stream eroded. Because the bed had grown larger, the Obion could carry more logs and sediment until that debris hit obstacles and eventually created blockages. That’s when the flooding started.
Parola and his lead engineer, Clayton Mastin, now tramp through fallen leaves alongside a newly restored section of the stream. Parola says the Stream Institute partnered with groups including local nonprofit, the Jackson Purchase Foundation, to begin the project. After years of studying the Obion area, they put a plan into motion in 2004 that would serve both the needs of the environment and the needs of farmers. He says in the past, environmentalists tried to keep humans activity far from preserved areas, but humans can’t stay away forever. "We have to restore areas that have been damaged and also provide for humans who work around the area that is being restored, so that’s the big challenge," said Parola.
The Institute’s solution included removing sediment from small, side streams and digging new channels to connect them, fortifying the channels with wood. This mimics the original path of the Obion. Clayton Mastin and his team have already dug 10,000 feet of new channel and will have excavated more than 20,000 feet by the time they complete the project in the next few years.
So far, they have only needed to remove four trees during construction. Mastin says they preserved those trees for replacement in the soil. “In terms of noninvasive construction techniques, it’s exciting because they didn’t have to go in and clear a 50-foot wide swath through forest," said Mastin.
The engineer says his team has even found a way to work around a beaver dam, leaving the animals and their home at peace. But Obion Creek Project Manager Andy Mowery says it’s not every day you can fix changes to nature so people should be careful. "I think most programs or people that do these kind of impacts don’t think too far into the future—they think five or ten years, not 50 or 100, and I think that’s where we get in trouble,” said Mowery.
In the areas that the Stream Institute has restored, knee high undergrowth protrudes from the mud. It began to develop once the murky water drained back into the Obion. In a few weeks, leaves will sprout from the trees and the vegetation will thicken, making it more difficult for Arthur Parola and his team to trudge through the woods.
But trudging through this forest with difficulty is better than sloshing through it. The Obion flows slowly now, and the creek is no longer in danger of losing its bends. The trees are no longer in danger of dying. Farmers no longer worry about lost cropland.