Little Tributary in Ohio Shows Big Results

Restoring Powder Lick Run wasn’t a massive project, but it was full of twists and turns and bumps. And that was the key to its success – putting meander and riffles back into a 3,600-foot reach of a stream that had been little more than a straight, eroding drainage ditch for generations.

The restoration of a 3,600-foot reach of Powder Lick Run included planting 2.7 acres with native vegetation and shrubs, and an additional 2 acres with 2,736 hardwood tree seedlings. Photos courtesy of Steve Phillips, Oxbow River & Stream Restoration

The whole 6-mile length of Powder Lick Run drains just 3.84 square miles in central Ohio. But as with anything else in geography, its importance is all about location, location, location. In Powder Lick Run’s small drainage are three egg farms, each a confined animal feeding operation (CAFO), and downstream in the Upper Scioto River is the intake for part of the system that supplies drinking water to the City of Columbus. Low dissolved oxygen levels, siltation and nutrient enrichment – boosted by seasonal spikes in nitrogen and atrazine levels – made Powder Lick Run a trouble spot. So did slumping banks, eroded by channelized water that pulled 150 tons of sediment into the stream each year. It was a tough prospect – biological value was dismal, and Ohio Environmental Protection Agency (Ohio EPA) figures it would take a 93 percent reduction in phosphorous loading to get Powder Lick Run into compliance with water quality standards.

The pollution problems also made Powder Lick a natural target for 319 funds channeled through the Ohio EPA. “This was the worst of the worst,” recalls Steve Phillips of Oxbow River and Stream Restoration in Delaware, Ohio, who headed up the team that restored part of Powder Lick Run with $189,000 in 319 funds. “It had the highest nitrogen levels of any stream in Ohio. If you could do anything there, you could do it anywhere.”

All Eyes on the Stream

Part of the challenge was that all eyes were on the stream – an array of best management practices had already been installed beyond its banks. “The egg farms did as much as they could on the land before we got there,” says Phillips. “The farmers had stopped applying manure on a watershed scale. There were filter strips beside the ditch. But there was such a buildup of phosphorus in the soils that they could quit farming it and we’d still have a problem for decades.”

Just as bad, Powder Lick Run itself demonstrated virtually no ability to assimilate the pollutants that were deposited into it. Nitrogen assimilation capacity was down to a paltry 0.29 mg/L per hour, the product of fast-moving water making very little contact with the microorganisms that could pull nitrogen out of the flow. “There was no level of management left that could reduce those pollutants to where they’d be OK if they got into a ditch,” says Phillips, “and once the water got into the ditch, there was not much difference than if they were putting it through a pipe.”

Oxbow Restoration redesigned Powder Lick Run in 2003, engineering in a series of meandering curves and creating benches of sand and gravel that serve as riffles between pools. The straight channel now winds in a path that is 5 times wider than the former ditch. A vegetated flood plain extends beyond the channel. The result is slow-moving water, more surface area and a floodplain for water to cover during flood periods – dramatic improvement in habitat as well as a marked improvement in nitrogen assimilative capacity (which jumped to 11.9 mg/L per hour).

Phillips says he prefers to engineer meanders that are 10 times wider than the channel, but the Powder Lick Run project was designed specifically to fit within existing filter strips. In all, 10 to 12 acres of easements would be required per mile rather than the usual 12 to 15 acres. “We wanted to build it within the existing buffer strips because that land had already been taken out of production,” he says. “We wanted to show that it could be done.”

Not only could it be done, but the little restoration is performing in high style. Tile drains empty onto the floodplain, notes Phillips. That precludes the need to shore up banks undercut beneath the tile, and minimizes the chance that high flows in the channel will plug up the drains. “There’s not maintenance,” he points out. “They don’t have to clean it, ditch it or dress the sideslopes.”

Better Alternative

Oxbow River & Stream Restoration used sand and gravel bars to create riffles in Powder Lick Run, slowing water flow and creating habitat. Photos courtesy of Steve Phillips, Oxbow River & Stream Restoration

The cooperators who worked together to put Powder Lick Run on the restoration map – DayLay Egg Farm, the City of Columbus, the Scioto River Federation, the Union County Soil and Water Conservation District, Ohio EPA and Oxbow – have made the restoration project a tourist site of sorts for regulators, hydrologists and farmers. Between 200 and 400 visitors have visited to see how it works over the past three years, and most have been very impressed.

“I think the results have been very promising, especially with respect to denitrification,” says Russ Gibson, nonpoint source manager for the Ohio EPA. “It clearly demonstrates that a channelized ditch is not as effective at assimilating nitrogen loadings, and that the restored design does, in fact, present a better alternative.”

The numbers bear out Gibson’s enthusiasm. Nitrogen loading has been reduced by 1,530 pounds per year thanks to the 3,600-foot restoration. Phosphorus loading is down 766 pounds per year, and sediment loading is down by 760 tons. Gibson says data like that is going to be necessary as regulators look for ways to reduce nutrient loading in water bodies, and landowners look for evidence that taking land out of production will be worthwhile.

Phillips says he’s most encouraged by the performance of the restored reach of Powder Lick Run on the state’s Qualitative Habitat Evaluation Index, which measures biological activity as an indicator of a water body’s condition. Back in 2003, Powder Lick Run couldn’t even pass muster under the Modified Warm Water Habitat standards. Today, it functions as a Warm Water Habitat, a huge jump to the category of a healthy little river. Oxbow also accomplished 1,500 linear feet of additional in-stream habitat improvement on Powder Lick, and is assembling projects that will increase the meandering restoration to a full mile of channel – a measure that Phillips considers to be a minimum for accomplishing significant downstream water quality improvements. Meanwhile, the City of Columbus has been funding easements for the floodplain along the restoration site.

Statewide, the next steps in understanding channel restoration will address how much engineering and earth moving is necessary, and quantifying the performance of meandering channels as drains, says Gibson. A pair of 319 grants for two-stage channel restorations is in the works for other waterways – an effort to try engineering some meander into a stream and then letting it go to find its own path, rather than constructing every twist and turn. No matter how the bends in a restored channel form, though, the evidence is growing that restoration can have profound impacts on water quality, even in highly impaired areas like the Powder Lick Run drainage.

“What Powder Lick represents, and what two-stage channel restoration represents, is that these are better alternatives to ditching,” Gibson says. “The full benefits of these types of projects are only beginning to be known.”