Rebuilding a Big Woods bottomland forest

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By Jay Harrod, August 2007

After digging 2.5 miles of channel, moving 4,000 cubic yards of earth, installing 38 log sills, and hammering in more than 4,000 black willow and button bush live stakes, Nature Conservancy staff and volunteers have nearly completed their work to turn a marginal Delta farm field into a bottomland forest and a ditch into a free-flowing stream, complete with restored meanders, riffles and pools.

Earthwork at Benson Slash Creek © TNC

After 60 years of use as an agricultural ditch, staff from The Nature Conservancy began restoring Benson Slash Creek in May 2006. Benson Slash begins north of Brinkley in Monroe County and flows into Bayou DeView, which meets up with the Cache River just a few miles south of Interstate 40.

“Our primary goals are to reduce sediment and improve water quality in Bayou DeView and restore habitat for native plants and animals,” said Conservancy Delta Project Manager Matt Lindsey.

Lindsey and Cache River Project Manager Josh Duzan measured the characteristics – depth, width, slope and the number and angle of curves – of nearby natural streams to design the channel at Benson Slash. By the end of fall, the Conservancy expects to complete the construction of the channel and nearby features, such as oxbow lakes and low-lying wetlands. When the construction is complete, they will also plant hundreds of oak and cypress seedlings along the new stream.

Benson Slash Creek restoration site © TNC

The restored section of Benson Slash Creek is surrounded by 435 Conservancy-owned acres that will be planted with approximately 13,000 seedlings by spring 2008 through the USDA Natural Resources Conservation Service’s Wetlands Reserve Program.

“We want to make this land look like it did before it was cleared and the stream was ditched,” Lindsey said. “This project will help connect some of the fragmented forests in the region. And, because bottomland forests filter sediment and nutrients, the project will improve water quality in Bayou DeView.”

Lindsey said there are thousands of miles of ditches that degrade water quality in rivers throughout the Delta, and the Conservancy is using Benson Slash as a demonstration site to help land managers working to restore similar ditches.

Measuring results

In 2006, The Nature Conservancy and the Arkansas Natural Resources Commission completed a study revealing that eroding ditches were a significant source of sediment in Bayou DeView and the Cache River. The Conservancy is now working with the Arkansas Natural Resources Commission on a three-year study to determine how much sediment from ditches ends up in these streams. To accomplish this task, the Conservancy placed seven water monitoring stations over the summer in tributaries – most of them ditches – of the Cache River and Bayou DeView. One was placed in a section of Benson Slash that remains ditched, just downstream of the restoration site.

Josh Duzan prepares to install a sediment monitoring station. © TNC

“The monitoring station will allow us to track how effective the project was at reducing sediment in Benson Slash Creek,” Duzan said.

The Conservancy’s next steps in its efforts to reduce in-stream sediment will be to determine which management practices are best at keeping sediment out of Bayou DeView and the Cache River. The restoration project at Benson Slash Creek will be just one method that’s measured. Other methods that might be studied include settling basins that capture sediment or better management practices for ditch maintenance.

“Farming is an integral part of life in the Delta and it’s critical to the nation’s welfare,” Duzan said. “The restoration work at Benson Slash is part of a ‘big-picture’ study. Ultimately, it’s about working with farmers to find ways to keep soil on their fields and out of ditches and streams. At the same time, though, we’re working to find ways to remove water from farm fields without moving sediment with it.”

Conservancy researchers have also begun monitoring for plants, fish and insects at the Benson Slash Creek restoration site and will continue to do so once a year over the next five years.

“I’m confident that data we collect years from now will reveal amazing results,” Duzan said. “We’re already seeing a significant increase in plant and animal species. Recently, we saw wood ducks in the new channel. It feels good to be part of a project to balance the scale that was offset here years ago when a meandering stream was transformed into a ditch.”

Learn more about the Conservancy's work in the Big Woods of Arkansas.