Lower Cedar watershed group tells Scott County board it has treated nitrates with cover crops, buffers and bioreactors

A team from the Lower Cedar Watershed Management Authority described work to reduce nitrate runoff and improve water quality in the Lower Cedar basin at the Scott County Committee of the Whole on Dec. 2.

Alyssa Comer, who handles technical administration for the WMA through the East Central Iowa Council of Governments, told supervisors the watershed covers "a little bit over 700,000 acres, 7 counties" and that the authority formed in 2018 to address water quality and flooding. Comer said a 2019 grant from the Iowa Department of Natural Resources supported a watershed plan that led to hiring a coordinator. "In November, we submitted a application for IDOL's water quality initiative, and this would be a 3 year program if awarded to continue to fund Emory in the watershed," Comer said.

Emery Davis, the contracted watershed coordinator with Heartland Co-op, described on-farm practices and outreach that the WMA uses to reduce nutrient loss. "Amounts to about 30,000 acres a year is what I work with farmers on," Davis said when describing cover-crop adoption across the basin. He outlined planting methods (high-boy sprayers, airseeders on vertical tillage rigs, even aerial application) and said the WMA supports those practices by arranging funding partnerships with Practical Farmers of Iowa and local NRCS offices to stack cost-share and make adoption economical.

Davis also described structural practices that treat tile drainage: saturated buffers and wood-chip bioreactors. "These remove about 50% of the nitrate that's in the water," he said, and noted the authority completed one 40-practice round and is contracting another 40 practices. He said saturated buffers are preferred because they are cheaper and long-lasting, while wood-chip bioreactors are a secondary option whose chips typically need replacement at about 15 years.

Board members asked technical questions about installation and maintenance (such as inlet and outlet elevations and how sediment is flushed from water-control boxes). Davis explained that the boxes are controlled by adjustable boards that set water height and that sediment can be removed by temporarily removing the boards. He also explained the WMA's "batch-and-build" contracting approach, where contractors are hired and paid in groups to avoid requiring landowners to front large construction costs; landowners receive a modest easement payment instead.

Supervisors expressed support while noting the scale of the challenge: a supervisor asked what percentage of the watershed the program reached after Davis cited 35,000 acres in a recent year. Davis and others said the WMA is seeking additional funding sources after ARPA support supporting the coordinator runs out.

The WMA team left board members with next steps for local project development and an appeal to consider WMA funding opportunities for nearby sites. The presentation concluded with the board thanking the presenters and noting interest in follow-up on potential local projects.

The board did not take a vote on the presentation; presenters requested additional funding consideration and indicated a pending state grant decision would affect continuation of the coordinator position.