The Iowa Conservation Reserve Enhancement Program (CREP) is a joint effort of the Iowa Department of Agriculture and Land Stewardship (IDALS) and the USDA Farm Service Agency in cooperation with local Soil and Water Conservation Districts that provides incentives to landowners to voluntarily restore wetlands targeted for water quality improvement in the heavily tile-drained regions of Iowa.
The goal of the program is to reduce nitrogen loads and movement of other agricultural chemicals from croplands to streams and rivers by targeting wetland restorations to the sweet spots on the landscape that provide the greatest water quality benefits. CREP wetlands are targeted to receive tile drainage by gravity flow, treating the water before it enters downstream waters.
In order to ensure wetlands are targeted to the most advantageous locations, IDALS uses advanced GIS analyses to find locations that are properly sized and situated to maximize water quality benefits. Wetland sizing and targeting criteria is based on two decades of research and monitoring by Iowa State University (ISU).
Research and monitoring by ISU shows that CREP wetlands can remove 40-70% of nitrogen loads from cropland drainage waters. Nitrogen reduction is primarily achieved through naturally occurring denitrifying bacteria in wetlands. Through denitrification, bacteria remove nitrate from the water and release it as nitrogen gas into the air as an innocuous end product.
In addition to improving water quality, these wetlands provide high quality wildlife habitat and recreational opportunities. The high quality buffers in conjunction with the shallow wetland habitats of these areas have proven to be a tremendous boon to a multitude of wildlife. CREP wetlands are particularly popular with duck and pheasant hunting enthusiasts and are widely used for these activities. From trumpeter swans to shorebirds and everything in between, these areas have shown that wetland restorations targeted for water quality benefits provide high quality habitat benefits as well.