A simple model for water table fluctuations in response to precipitation

A simple physically-based model is developed for quantifying groundwater fluctuations in response to precipitation time-series. A semi-analytical solution of the governing differential equation is derived for relevant initial conditions and an efficient numerical algorithm is presented. Model performance is assessed by comparing predicted and observed groundwater fluctuations over a multi-year period in response to precipitation data for a site in the Hongcheon area of South Korea. Groundwater fluctuation and precipitation time-series during the year 2001 are used for model calibration. The calibrated model is then used to predict groundwater fluctuations for 2002–2004 from measured daily precipitation data. Prediction variance is only slightly larger than the calibration variance. Results indicate that model parameters are stable over time and that reliable water level fluctuation predictions can be made by the model from actual or projected precipitation data following calibration for a limited time-series.