A MULTI-EVENT TIME SERIES APPROACH FOR GROUNDWATER RECHARGE QUANTIFICATION AND MAPPING

Accurate measurement of groundwater recharge is hampered by limited observations. Therefore, finding reliable techniques for quantification and mapping of groundwater recharge is crucial. In this research, we present a multi-event time series approach that infers groundwater recharge from both precipitation and water table records. Our methodology incorporates a specific yield variable from the USGS report, utilizing data obtained from a raster map derived from contour maps of specific yield ranges in the high plain’s aquifer. The study includes a recharge estimate for 37 wells located mainly in the eastern central part of the study area. Selection criteria for boreholes required consistent and continuous time series water table data for a minimum of 3 years. Analysis covered borehole data from 1947 to 2022, under the assumption that the hydrogeological parameter response of each borehole remains constant unless interrupted by anthropogenic effects. Our findings indicate that the recharge rate varies between 29 mm to 260 mm per annum, equivalent to 5% to 70% of total precipitation per water year. Moreover, it was observed that recharge quantification is influenced by pumping and specific yield factors.