Though Harrow's Branch residents have voiced concerns that flooding has worsened since levees were installed, Seals said that's not what this project will address.
"Their complaint is flooding, but if you have a 7-inch rain event in ... an hour, you're going to have flooding no matter what we do," he said.
The solution, Altheide said, is to create smaller sediment control basins and erosion control structures. A sediment control basin is "an earthen structure with a tile outlet that temporarily holds water and releases it slower," she said.
The erosion control structure is similar, though it permanently holds water — "it looks like a pond to you and I." The structure catches sediment and slows gully erosion, which then improves water quality.
Memorial Park also contributes to poor water quality, though its watershed is much smaller than Harrow's Branch.
The pond in Memorial Park has silted in over the years, Seals said.
"We cleaned it once [in 2004] but it silted up again," he said. "It has a lot of bank sloughing and soils that are carried down into the pond."
But the silt continues to erode into the pond, estimated at 232 tons per year.
"What happens is it fills in with sedimentation, and when it does that you don't have the aquatic fish type habitat in there because it's so full of sediment," Altheide said.
That pond feeds into the Des Moines River, so protecting it will improve water quality.
But the park's soil health also needs to improve, which will help its ability to absorb water so there isn't as much run-off. To accomplish this they'll use "aerating practices on the park's lawn area," she said.
"If you go out and walk there, it's hard and doesn't have a lot of organic matter," she said. "It doesn't have the root growth going down into the lawn for a very long distance, so the water just isn't able to infiltrate as it would if it had better health."