COLUMBUS, Ohio — About a decade ago Andy Ward, a professor in the food agriculture and biological engineering department at The Ohio State University, began investigating drainage ditches.

As a result, he designed a two-stage drainage ditch that can benefit both agriculture and the environment. More than 30 of these ditches have been built in Indiana, Michigan, Ohio and Minnesota. The farmers who constructed them are pleased with the results.

Ware started on his quest because, “We got the sense that probably a lot of ditches were being cleaned that didn’t really need to be cleaned, and secondly, when cleanout was done, it was actually destroying a natural recovery process,” he said.

“What nature was trying to do was recover this human-constructed ditch and try to make it more like a stream system.”

If he could predict what was going to happen in the bottom of a ditch, Ware thought that he could come up with an alternative maintenance practice that would have less impact on the system and be more sustainable.

“We figured out how to predict what would happen and we came up with a two-stage ditch concept where, instead of cleaning out the bottom of the ditch, we actually created a floodplain,” he said.

“We pulled back the sides of the ditch and we created a bigger bench at the bottom; it was like a miniature floodplain. We left the existing channel and the vegetation that was there so we had a much lower impact.”

The design of a two-stage ditch consists of: a channel that is sized to convey the effective discharge; a bench to serve as a floodplain for the smaller channel; and a stage of adequate width to prevent flow overtopping the ditch banks and flooding the surrounding land.

This design results in a drainage channel system that can benefit both agriculture and the environment. It provides some water quality benefits and there is some evidence it would reduce nutrient and sediment discharges, Ware said.

“The system is more stable, there is less scour and you now have a saturated bench with vegetation in it,” he said. “It is acting like a biological treatment system, just like a buffer strip would at the top. All of the treatment benefits that you might get in a wetland you might also get in a two-stage ditch system.”

The longest ditch built has been in place 10 years, Ware said. In that time, there has been little detectable change in it.

“The farmer said he has never seen the water run so quiet,” Ware said. “That attests to how there is less scour potential, more stable. Another farmer said he has never had a wetness field in the field since we built the ditch. He saw it as a very positive benefit to his farming system. The second farmer, in Ohio, said that every ditch in America should be built this way.

“The downside for the farmer in practice is they’re not getting the credit for having a grass buffer in the bottom of a ditch. There is a permanent loss of land because you’re making the ditch bigger.”

In Indiana this practice is eligible for cost-sharing funds through government programs, but that is the only state, Ware said.

Jon Witter and Jessica D’Ambrosio, with OSU extension and the Ohio Nonpoint Pollution Education Program have worked with Ware on the projects. To see a video about the two-stage ditches online, visit http://vimeo.com/ 7901535