Jessica Oster, of Iowa Learning Farms, teaches Kyden O’Neill, 6, of Des Moines, about soil conservation techniques through a demonstration in which children spray colored water on a board representing various types of land uses. The game shows children how agriculture, commercial and residential land all impact soil erosion. The demonstration was part of Saturday’s activities celebrating the 40th anniversary of the creation of Big Creek Lake near Polk City.

By DAVE DEVALOIS

Farm News staff writer

POLK CITY – Big Creek Lake and the surrounding Big Creek State Park turned 40 this year and continues to attract hundreds of thousands of central Iowans each year to its waters for fishing, boating, swimming, and to its bike trails, beaches, playground, marina, picnic shelters and other amenities.

But if one were to look closely, Big Creek is showing its age. Water from Big Creek flows in from three creeks and all three sources have silt dams filling with sediment.

Water quality has gradually diminished and, at times over the past several summers, the beach was forced to close due to harmful bacteria in the water. Algae blooms are common as the nitrogen-rich water reacts to summer heat.

So, what can be done to restore the popular 780-acre lake to its former glory, when it used to rank as one of the best fisheries in Iowa? Organizers of the Big Creek Lake Watershed Project are looking at everything related to soil erosion within the 48,000-acre watershed for possible solutions.

The watershed project is led by Sean McCoy and Zach DeYoung. McCoy is with the Boone Soil and Water Conservation District, while DeYoung is with the Polk Soil and Water Conservation District.

Both coordinators are careful not to point fingers and blame one particular source for the problems at Big Creek. But with 81 percent of the watershed’s acreage in row-crop agriculture, cooperation with farmers in Polk and Boone counties is essential toward making progress.

“We know farmers are just trying to make a living,” McCoy said. “We have to find a way to live within those means and improve water quality.”

So far, the coordinators have documented watershed data. DeYoung walked 50 miles of creeks in the watershed to gather firsthand information on what drained into the creeks. Then, the coordinators drove throughout the 75 square miles of the watershed to document whether the land was cropland, grassland, timber or residential.

The Big Creek Lake Watershed Project is offering farmers with land within the watershed enhanced cost-sharing for specific soil conservation projects, such as grassed waterways, ponds, bank stabilization, terraces and pasture or hayland management.

Projects such as these typically have a maximum of a 50 percent cost-share, but new grant opportunities have increased the cost-share up to 90 percent, meaning that a farmer would have just 10 percent of the burden.

So far, interest among farmers in the watershed has been tepid, but McCoy is optimistic that farmers will come around and realize the projects benefit them as well as the lake. He recalls seeing fields after a heavy rain in April showing obvious soil erosion.

“A lot of these guys are going to realize they need the waterways on their farms,” McCoy said.

The coordinators said they understand their biggest obstacle right now might be the value of the corn crop during the past few growing seasons.

“It’s a business right now that is making a lot of money and the more acres they farm, the more money they make,” McCoy said.

McCoy and DeYoung said they are looking at other areas to improve water quality. They identified 11 gullies within the state park itself where soil is eroding from steep banks. Silt dams will be built on each of the gullies to mitigate the erosion. DeYoung said that project itself could prevent tons of soil from reaching the lake.

During an event commemorating Big Creek’s 40th birthday, other groups tried to educate Iowans about soil conservation and land use.

Jessica Oster, with Iowa Learning Farms, used a simulation to show children how various land forms can cause pollution and/or soil erosion.

Another demonstration showed the soil erosion, or lack of it, during heavy rains on bare soil, compared low-till conditions or grassland conditions.

“Our goal is to get people talking with their communities,” Oster said. Iowa Learning Farms, which is a program of Iowa State University, will have discussed these iossues with people in 94 of Iowa’s 99 counties by summer’s end, Oster said.

Contact Dave DeValois at dwdevalois@yahoo.com.