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- Dave Liebl was doubtful about building a dam in the middle of a field, but his wife Karen convinced him that something had to be done to halt the gully erosion eating away their topsoil. “Now I think it’s one of the best things I’ve done.”
- The Liebls’ first two water- and sediment-control dams were so effective at halting gully erosion that they invested in five more for other fields. “We haven’t lost one bit of production from the dams,” says Dave. On the contrary, he says, before the sediment dams were installed, “there were places where we didn’t get a crop because of the gully.”
- To other doubters, Dave says: “Some complain about having to farm around them, but it’s a small price to pay for keeping your soil.”
Water- and sediment-control basins are a time-tested way to prevent field gullies in hilly fields with irregular topography, says Jeff Hellermann, NRCS district conservationist, Stevens County, Minn.
Downsides of WASCOBs
The cost of a WASCOB varies with the site, but a typical structure that can be farmed over costs around $5,000, including the tile line, Hellermann says.
Most farmers prefer to install broad-based dikes that can be cropped, if the site permits, says Illinois’ Scott Wallace, “but the downside is the amount of soil it takes to build them. A narrow, all-grass ridge takes two-thirds less soil and is much cheaper to install. It’s just as effective as a broad-based dam and more durable.”
Sediment dams are also quite a bit more expensive than a grassed waterway, especially if built in a series, although many farmers consider WASCOBs a better value, long-term, Wallace says. And there are a variety of federal, state and local cost-share incentives that can cover up to 75% of installation. Subsidies vary by state, so check with your local NRCS office.
Field logistics are another challenge, Wallace says. Often, the dikes can’t be aligned with the preferred farming direction. They pose an obstacle for wider planters and combines, too, he says, “although we try to make them fit equipment sizes.”
Gullies that straddle property lines can also be a hurdle. Doug Backman, an Alberta, Minn., farmer, is leading an effort to fix a long gully that cuts through a quarter section of land he bought last year.
The channel, which collects water from a 100-acre watershed, begins on his neighbor’s land, angles across Backman’s new farm, and deposits tons of sediment on a third farmer’s land. At first, Backman thought he could take care of the problem on his own, but he soon realized that he’d need cooperation from his neighbors to stop the erosion. “We got everybody together and it’s been a good experience.”
The $105,000 project includes 17 water and sediment-control dams on the two upland farms. The downslope landowner is providing access to an outlet through a new 18-in. tile line. “They recognize the benefit they will get, too,” Backman says. “They get all the silt on their land, and it smashes the crop.”
Backman has experience farming around WASCOBs on some of his rented land. In terms of field operations, the dams are “a bit of a disadvantage,” he says. “But the advantages outweigh the disadvantages. When the topsoil is gone, there’s no fix.”