The Oak Openings Region in Northwest Ohio originally consisted of oak savannas, wet prairies, oak woodlands, oak barrens and floodplain forests. Currently, the Oak Openings supports globally rare oak savanna and wet prairie habitats, and it is home to more rare species of plants and animals than any other area in Ohio. The wet prairies in the region have been drained by ditches and encroached by invasive plants (mainly glossy buckthorn - Rhamnus frangula).
What are the hydrological implications of a particular invasive species (glossy buckthorn) on a wet prairie? What would happen with the water table if all the invasive species is removed? What is the effect on the water table from actions like the removal of a ditch or increased urbanization?
A shallow groundwater model was implemented using the Gridded Surface Subsurface Hydrologic Analysis (GSSHA) software to simulate the groundwater and surface water interaction in the hydrologically complex area around Wiregrass Ditch in the Oak Openings Region of Northwest Ohio. The implemented GSSHA model simulates physical processes such as infiltration, evapotranspiration, snowmelt, overland flow, and interaction of groundwater with ditches. The model was calibrated using a time series of water table elevations collected in the field.
Results/Conclusions
Preliminary results show an increased on ponding water depths, water table elevations, surface moisture, and ditch water depth when the wet prairie is restored by removing the invasive species. The results also show a depression of the water table if urbanization is increased, and a modest raise in the water table if the main ditch in the area is removed.
Although the model tends to under-predict water table elevations, statistical analysis indicate a good fit between observed and simulated water table elevations. The output of the model such as, water table elevation maps, hydrographs, flood grid maps, soil moisture distribution maps, ditch water depths etc. is a useful tool for the preservation of natural areas as it accurately predicts the response of water table elevation and discharge to ditches from precipitation events.