Submitted to: ASAE Annual International Meeting
Publication Type: Proceedings
Publication Acceptance Date: 4/1/2000
Publication Date: 7/9/2000
Citation: ALLRED, B.J., FAUSEY, N.R., COOPER, R.L., BROWN, L.C., CLEVENGER, W.B. WATER TABLE MANAGEMENT GUIDELINES FOR A WETLAND RESERVOIR SUBIRRIGATION SYSTEM. 2000. ASAE PAPER NO. 002040. Interpretive Summary: Improved crop yields are one of the primary benefits of a Wetland Reservoir Subirrigation System (WRSIS), especially during dry growing seasons. However, before this benefit can be achieved, proper water table management procedures need to be followed. Experience based guidelines for WRSIS water table management are presented and the operational practices suggested varied somewhat depending on whether the growing season was wet, normal or dry. Wet years require the most water table management effort and the principal goal, under these conditions, is preventing crop damage from root zone flooding. In a dry year, WRSIS crop yields are often quite good, providing that water is conserved for use during the most moisture sensitive growth stage of the plant. One lesson learned at two of the three WRSIS sites that are now operational is that the initial design may require modification to better manage water table conditions. In particular, installing additional hydraulic control structures to partition a subirrigated field into separate water table management zones can solve the problem associated with flooded soils in lower elevation areas. An extensive hydraulic/hydrologic monitoring program has now been implemented at one of the three WRSIS sites. The information collected will be used to make refinements in water table management guidelines, thereby further improving WRSIS crop yields.
Technical Abstract: A Wetland Reservoir Subirrigation System (WRSIS) allows for capture, treatment, storage and reuse of subsurface drainage and surface runoff waters within an agricultural setting. WRSIS components include an underground drainage pipe network tied to both a constructed wetland and a water storage reservoir. With this type of system in place, the subsurface drains can be used to either add or remove water from the root zone, thereby enhancing crop yields, especially in dry years. Obtaining these crop yield benefits requires proper water table management. Three WRSIS sites have been in place for several years within the Maumee River Watershed portion of northwest Ohio. Along with prior subirrigation research, operational experience and crop yield measurements at the three test locations have resulted in site design refinements and the development of guidelines for improved water table management. The WRSIS water table management guidelines described in this paper vary somewhat depending on whether wet, normal or dry conditions exist with respect to growing season rainfall. An extensive WRSIS monitoring program has now been implemented and in addition to the corn/soybean crop yield measurements, information on water movement, storage and quality within the system will be used to fine-tune water table management guidelines even further.