An improved time series approach for estimating groundwater recharge from groundwater level fluctuations

An analytical solution to a linearized Boussinesq equation is extended to develop an expression for groundwater drainage using estimations of aquifer parameters. This is then used to develop an improved water table fluctuation (WTF) technique for estimating groundwater recharge. The resulting method extends the standard WTF technique by making it applicable, as long as aquifer properties for the area are relatively well known, in areas with smoothly varying water tables and is not reliant on precipitation data. The method is validated against numerical simulations and a case study from a catchment where recharge is "known" a priori using other means. The approach may also be inverted to provide initial estimates of aquifer parameters in areas where recharge can be reliably estimated by other methods.