Recharge Estimation of Andassa River Catchment, North-western Ethiopia

Estimating the recharge amount and investigate the hydrogeology of a given area is essential for sustainable management of groundwater resource. The objective of this study was to estimate groundwater recharge of Andassa catchment using chloride mass balance, base flow separation, soil moisture balance, water balance methods, and hydrogeologicalcharacteristics of the catchment. Meteorological, river discharge, pump test data together with well completion reports were used to estimate the recharge value and characterize the hydrogeology of the catchment. The average recharge value of the area is 307.3mm/year. There are tertiary and quaternary formations in the study area. The groundwater bearing formation of the area is grouped as: very low, low, moderate, high and very high aquifers based on transmissivity, yield of the borehole and springs. Very high productive aquifer in the low lands is recharged from regional groundwater flow and the middle elevated areas aquifer mainly shows local recharge.