By MATT MILNER
Courier staff writer
---- — OTTUMWA — Blakesburg and Ottumwa are both being recommended for funding to help clean up waterways in the area.
The draft list of recommendations for the state's revolving fund for water and wastewater infrastructure includes more than a half-million dollars for Ottumwa, focused on Harrows Branch and Memorial Park.
The goal at both locations is to reduce storm runoff and sediment. The amount of sediment delivered by Harrows Branch is estimated at 3,487 tons per year. Memorial Park is estimated at 232 tons per year.
The project for Harrows Branch targets a 123-acre area with ponds, sediment basins and terraces. Just as fast water will more easily wash away soil, slower water, like that in ponds and basins, allows the sediment to fall out of the stream. That reduces the amount that eventually winds up being washed away.
Work at Harrows Branch sets an 8.3 percent reduction in sediment as the goal. That doesn't sound like much, but it's equivalent to 288 tons per year.
Memorial Park is a smaller area, 48.5 acres, but the goals there are twofold. First, the draft plans call for increased filtration in the park by improving soil quality and timber. That should create more capacity for holding rainwater with a goal of being able to keep an additional 1.25 inches of rain. That's equivalent to 67,500 gallons of water.
Work in Memorial Park will also seek a 76 percent reduction in the amount of sediment that runs out of the park though construction of ponds and sediment basins. That would represent a drop of 177 tons of sediment per year.
At Blakesburg, the proposed project focuses on tributaries to the South Avery Creek. High levels of phosphorus and nitrogen, as well as large amounts of sediment cause problems.
The $45,000 project will focus on stabilizing a gully, which should reduce erosion, as well as efforts to trap sediment and stabilize the grades leading to the creek.