Comparison of Selected Methods for Estimating Groundwater Recharge In Humid Regions

Method:	Category:	Spatial Scale:	Temporal Scale:	Quantity Estimated:	Ease of Use:	Data Needs:	Cost:
Deep Percolation Model	Water Budget	Regional	Day to Years	Potential Recharge	Moderate	Moderate	Moderate
The Deep Percolation Model estimates, on a daily-basis, the long-term average groundwater recharge from precipitation. It was developed by USGS to simulate the recharge in large areas with variable weather, soils, and land uses. The model incorporates areal distribution of precipitation, potential evapotranspiration, snow accumulation, evaporation and melt, interception by plant foliage and evaporation of intercepted moisture, surface runoff, soil moisture accumulation and evaporation, transference of unused energy, and plant transpiration. The minimum data sets required are daily values of precipitation and maximum and minimum air temperature, soil thickness, and available water capacity, soil texture, and land-use. It is relatively easy to use with data available meteorological, land cover, and soil datasets. The FORTRAN computer code is available from USGS.