Modifications of Historic Wetland-Prairie Hydrology, Northwest Ohio, and Influences on Groundwater/Surface-Water Interactions
Conference Poster (Faculty180)
Wetland Prairies of Northwest Ohio are smaller components of broader hydrogeologic systems so their hydrology is controlled by surrounding sub-systems. As part of the historic Irwin Prairie, the Wiregrass wet prairie is comprised of upland sand ridges, intermediate transitional areas, and the wet prairies themselves. Investigating the groundwater flow and storage within the Wiregrass unconfined aquifer involves investigating hydrologic interactions with the wet prairie as groundwater flows from areas of recharge in the upland dunes, through the transitional zone, and finally to the wet prairie around Wiregrass Lake. The hydrogeology of these systems was monitored during the transition from fall into spring to observe the effects of changes in groundwater recharge and discharge on the groundwater/surface-water interactions. Hydraulic conductivity, specific yield, groundwater flow regimes and fluxes were quantified using fields of piezometers in each of the subsystems with pump tests and by monitoring the heads throughout the seasons. Numerical modeling indicates that, in the winter and spring, gradual widespread recharge occurs in the upland areas as groundwater storage increases. This increase in storage increases the flux through the transitional area during the spring and early summer. The groundwater flux is then discharged to the surface water bodies in the wet prairie area. Because human modification to drainage lowers the water table in the vicinity and diverts groundwater flow, the broader hydrologic system is separated from the Wiregrass wet prairie system. As a result, the wetlands have been converted from groundwater discharge areas to wetlands that lose water by leakage through the hydric soils.
