Combining WetSpass and MODFLOW to assess the groundwater recharge in the agricultural highlands of Ethiopia

Abstract

Estimating the temporal and spatial patterns of recharge is crucial in Jedeb Watershed, which has shallow aquifers, a proliferation of wells, and limited observations. This paper uses the WetSpass-MODFLOW coupling to evaluate the groundwater recharge in the Jedeb watershed. The ArcGIS tool is used to build grid maps that contain the input data for the WetSpass-M model. These findings are then used to simulate the hydraulic head distribution in the groundwater flow simulation program MODFLOW. WetSpass-M calculated that long-term spatial and temporal average annual precipitation of 1394 mm is distributed as 99 mm (7.1%) groundwater recharge and 722 mm (51.79%) surface runoff, while 574 mm (41.11%) is lost through evapotranspiration. In such seasonal variations, the groundwater level due to the annual stress period varied from 2164.2 to 2213.1 m. The findings contribution could serve as a benchmark for future research by researchers, policymakers, and specialists in regional water resources.