Evaluation of the Glugla method for estimating evapotranspiration and groundwater recharge

Estimates of groundwater recharge are often needed for a variety of groundw ater resource evaluation purposes. A method for estimating long-term ground water recharge and actual evapotranspiration not known in the English liter ature is presented. The method uses long-term average annual precipitation, runoff potential evaporation, and crop-yield information, and uses empiric al parameter curves that depend on soil and crop types to determine long-te rm average annual groundwater recharge (GWR). The method is tested using hi storic lysimeter records from 10 lysimeters at Coshocton, Ohio, USA. Consid ering the coarse information required, the method provides good estimates o f groundwater recharge and actual evapotranspiration, and is sensitive to a range of cropping and land-use conditions. Problems with practical applica tion of the technique are mentioned, including the need for further testing using given parameter curves, and for incorporating parameters that descri be current farming practices and other land uses. The method can be used fo r urban conditions, and can be incorporated into a GIS framework for rapid, large-area, spatially-distributed estimations of GWR. An example applicati on of the method is given.