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An innovative agricultural water management system has been developed and is now being tested to determine efficacy for reduction of nonpoint source pollution. Widespread utilization of this system could substantially reduce many of the Midwests agriculturally related environmental problems. Called a Wetland Reservoir Subirrigation System or WRSIS for short, the system is comprised of a wetland and a water storage reservoir 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 a 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 and held until needed to subirrigate crops during the dry part of the growing season. Depending on placement location within the system, weir-type hydraulic control structures are used to manage the water table in cropland, regulate surface water levels in the wetland, or limit offsite discharge. The designed integration of the various components allows 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.

There are three field-scale WRSIS demonstration sites located within the Ohio portion of the Maumee River Basin, one each in Defiance, Fulton, and Van Wert Counties. All 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. 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 in soil, 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. The other potential benefits are being assessed through an environmental-hydrologic-hydraulic monitoring program that has recently been implemented.