State seeks more wetlands to fight pollution runoff

By Philip Brasher
February 8, 2009; Des Moines Register

Adel, Ia. – State agriculture officials think they have the solution to the pollution problems caused by water that drains off the state’s farms: Drain the water faster.

Shallow ponds like the one created with federal money on a Dallas County farm can destroy much of the pollution that runs off neighboring corn fields and eventually into Des Moines-area water supplies and on to the Gulf of Mexico.
The ponds hold the water long enough for bacteria to destroy nitrates that the water contains.

But few landowners are willing to give up cropland to create marshes, not with the price of corn and soybeans at historically high levels.

So the state Department of Agriculture and Land Stewardship has come up with an idea that could make wetlands more enticing. Landowners would be allowed to replace the century-old network of drain pipes that snake under much of north-central Iowa in exchange for allowing property to be converted into wetlands.
The theory is that newer, larger pipes would drain farms faster, increasing crop yields significantly and boosting farm income, while the new wetlands would trap pollutants coming off the fields.

The wetlands would improve water quality for cities like Des Moines and help shrink an oxygen-depleted dead zone in the Gulf of Mexico that is blamed on runoff of fertilizer from Midwest farms.

"We can’t continue to deliver nitrates and phosphorus to the Gulf in the rates that it’s going," said Chuck Gipp, director of the state agency’s soil conservation division. "The upper Midwest is impacting what happens in the Gulf."
The agency wants $31 million in federal money for 25 pilot projects to see how the plan works. Without voluntary measures, the federal government could eventually impose regulations on farm runoff, Gipp said.

A federal task force has called for reducing nitrate and phosphorus loads in the Mississippi River basin by 45 percent to cut the dead zone in half.

Wetlands aren’t the only way to stop farm chemicals from getting into streams and rivers. Converting fields near streams to grass or planting cover crops also can help.
Many environmentalists normally would worry about increasing drainage from farm fields. But some of them are backing the plan because of the potential impact of the new wetlands on water quality.

"If you can strategically locate those wetlands on the landscape for nitrate removal, you can get fairly significant reductions," said Susan Heathcote, water program director of the Iowa Environmental Council. "The problem is getting enough of them out there to make a difference."
The Dallas County wetland was created by building a dam of steel plates and earth along a stream that is fed by water draining from more than 700 acres of neighboring land. The bacteria in the pond should remove on average about half of the nitrates in the water before it heads for the Raccoon River, according to Iowa State University research.

Wild rye, blue stem and other grasses grow in and around the water, preventing erosion and providing a source of food for the nitrate-munching bacteria. A ladder-like device buried in the berm serves as a relief valve to keep the pond’s water level at or under 3 feet, low enough so that the plants – and bacteria – can survive. On this farm, beavers have made controlling the water level a challenge because of their insistence on creating their own dam, using corn stalks they slide down to the pond from the neighboring land.
This wetland is one of 35 constructed so far under the Iowa Conservation Reserve Program, which is funded jointly by the state and the U.S. Department of Agriculture. The state has identified another 446 potential sites where it would like to sign up landowners.

Even though landowners receive a yearly check for the acreage converted to wetlands, only one in eight contacted by the state typically accept the offer.

At that pace, "we’re decades and decades" from achieving a 45 percent reduction in nitrate runoff, said Shawn Richmond, who coordinates the wetland program.
That’s where the pilot projects come in.

Experts say landowners could increase crop yields in north-central Iowa, one of the world’s most fertile regions, as much as 20 percent by installing new underground drains.

However, replacing the drains can run afoul of USDA environmental rules. The region is pocked with depressions that are classified as wetlands because they frequently fill with water during the spring. The USDA regulations bar such areas from being drained, even though farmers seed them to crops every year, unless an equal amount of wetland is created somewhere else – at the landowners’ expense.
State officials say the pilot projects will show landowners that creating the permanent new wetlands, which would be designed for nitrate removal, would be worth the cost. Crop yields on the land where new drains are installed would improve so much that the projects could pay for themselves in two to three years, the officials say.

The projects could have environmental benefits beyond just removing nitrates from the water. Increasing the size of the underground drainage would mean more water would be filtered down through the soil into the pipes, removing phosphorus and pesticides on the way, rather than running off the surface, said Bill Crumpton, an expert on wetlands at Iowa State. Wetlands by themselves have little impact on phosphorus or pesticides in water.
Doug Adams, who farms near Humboldt, said the projects make sense, though it will be challenging to get some landowners pay their share. The state or federal government is likely to going to have to subsidize the cost, he said.

"Our tile (drainage) system is totally overloaded. By the time my water goes down, the crop has already been lost," he said.

The state agency wants federal funding to pay half the cost of the drainage work on the pilot projects. Later, landowners would be expected to pay it themselves.
Having former Iowa Gov. Tom Vilsack as U.S. agriculture secretary should help in getting federal help, but a lot will depend on the lower-level appointees who will oversee conservation spending, Gipp said. Nominations for key positions in the USDA haven’t been announced other than a handful of advisers.