This map contains the data used in the study 'Estimation of average diffuse aquifer recharge using time series modeling of groundwater heads'. In this study a new method is presented to estimate average diffuse aquifer recharge of water table aquifers in temperate climates using time series analysis of water table level fluctuations. Recharge is estimated from time series models fitted to observed heads under the additional constraint that the seasonal harmonic of the observed head is reproduced as the sum of the transformed seasonal harmonics present in precipitation, evaporation, and pumping. The method is applied to measured heads obtained from piezometers situated on and around the ice-pushed sand ridge of Salland in the Netherlands. Results are compared with recharge estimates based on the saturated zone chloride mass balance. The data are ascii text files saved in the following compressed maps: - Groundwater_chloride_concentration.zip - Groundwater_head_time_series.zip - Makkink_reference_evaporation_time_series.zip - Measured_precipitation_time_series.zip - Precipitation_chloride_concentrations.zip - Pumping_time_series.zip For further details, please refer to the readme files contained in each submap.