|Fausey, Norman - Norm|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 9/12/2002
Publication Date: 7/27/2003
Citation: FAUSEY, N.R., ALLRED, B.J., BROWN, L., CLEVENGER, B., REITHMAN, D., CHESTER, P., THORNTON, C. RECYCLING OF RUNOFF AND SUBSURFACE DRAINAGE WATER IN THE MIDWEST U.S. (WETLAND RESERVOIR SUBIRRIGATION SYSTEMS -WRSIS). MEETING ABSTRACT. 2003. Interpretive Summary:
Technical Abstract: An innovative agricultural water management system has been developed and is now being tested to determine efficacy for reduction of nonpoint source pollution of surface water streams. Widespread utilization of this system could substantially reduce many of the Midwest's agriculturally related environmental problems. Named a Wetland Reservoir Subirrigation System or WRSIS for short, the system includes a constructed wetland and a water storage reservoir which are linked to a network of subsurface pipes used at different times to either drain or irrigate crops through the root zone. Runoff and subsurface drainage are collected in the constructed wetland. Natural processes allow the wetland to partially treat the water through removal of nutrients, pesticides, and sediment. The water is then routed to a storage reservoir where further treatment can occur. The water may be held until needed to subirrigate crops during the dry part of the growing season, or released to the stream to create additional treatment and storage capacity. Adjustable weir type hydraulic control structures are used to manage the water table in the cropland, water levels in the wetland, and offsite discharge. The integration of the various components allows the WRSIS to operate in a closed loop mode most of the time, with the consequence that water is released outside the system only under controlled circumstances. Three field-scale WRSIS demonstration sites located within the Ohio portion of the Maumee River Basin have been in operation long enough to experience five to six complete growing seasons, but the infrastructure to measure and sample water quantity and quality has been in operation less than two years. Two of the sites are on private farmland and are farmer managed. Although confirmation will require continued long-term data collection, the expected benefits from WRSIS include greater crop yields, additional wetland acres and wildlife habitat, decreased flooding potential downstream, more carbon sequestration, and reductions in the amount of nutrients, pesticides, and sediment discharged into local waterways. Compared with control plots, WRSIS has already demonstrated crop yield increases that are especially substantial for dry growing seasons. Suitable wetland vegetation has developed naturally at each site and there is substantial use of the habitat within and surrounding the wetland by numerous wildlife species. The other potential benefits are being assessed through an environmental-hydrologic-hydraulic monitoring program that has recently been implemented and that will be illustrated and discussed. Cost analysis indicates that construction costs for this type of system will need to be partially reimbursed through public funding to ensure that the environmental benefits can be realized. The crop production benefits are not adequate to fully offset the cost of construction.