CREP Funded Wetland Development

Buena Vista County, IA | Water

ISG partnered with the Iowa Department of Agriculture and Land Stewardship (IDALS) and Conservation Reserve Enhancement Program (CREP) to design a treatment wetland in Buena Vista County; the largest IDALS sponsored wetland treatment project in Iowa.

A 5,548-acre watershed in Buena Vista County was identified through Iowa State University and the Iowa Department of Agriculture and Land Stewardship as a wetland treatment opportunity to reduce nitrogen loads and the transport of other agricultural chemicals from croplands into streams and rivers.

Directly treating water headed into the North Raccoon River, the CREP project required collaboration and trust from five landowners to develop the 56.5-acre of permanent pool area. A permanent pool treats tile discharge from four interior drainage districts and a portion of a fifth district. A relay of almost one mile of District tile was installed to ensure drainage rights and accommodate the development of the large wetland pool. The Board of Supervisors, as Trustees of the districts, and landowners within those districts, chose to upsize the relayed tile at their own cost as a part of the project, which required the development of a maintenance agreement and an informational landowner meeting. As district engineer, ISG assisted with the permitting process in accordance with the US Army Corps of Engineers.

Using advanced software technology, ISG used an XPSWMM model to account for existing potholes and take advantage of existing storage in the region. A productive working relationship with the County’s engineer resulted in a voluntary upsizing of road culverts immediately downstream from the sheet pile weir to accommodate peak flows.