The search for new groundwater resources in northern Ethiopia and the development of groundwater models to control and manage the resource are rooted in the water scarcity and the socio-economic importance of the water demand for agriculture and domestic use. In this paper, WetSpass-MODFLOW coupling was used to assess groundwater recharge of the Hormat-Golina sub-basin. This paper aims at determining the groundwater recharge in the Hormat-Golina sub-basin, which will be followed by simulating the hydraulic head distribution using the MODFLOW groundwater flow simulation model. The steady state groundwater flow calibration was achieved by comparing measured and simulated hydraulic heads. WetSpass also calculated the mean annual evapotranspiration, surface runoff, and groundwater recharge to be 516.6, 204.9, and 35.6 mm, respectively. Groundwater recharge represented 4.7% of precipitation, whereas actual evapotranspiration and surface runoff represented 27% and 68% of precipitation, respectively. For this type of seasonal variation, the range of groundwater head distribution is 9.37 to 29.86 m during the winter (dry season), 9.53 to 29.89 m during the summer (wet season), and 9.58 to 30.17 m during the annual stress periods (recharges). The predicted hydraulic heads in steady state match the measured heads well for all stress periods (summer, winter, and annual recharge) with a correlation coefficient of 0.86. Future groundwater resource development plans for the valley must be balanced with groundwater recharge rates and projected abstraction rates for agriculture and domestic water supply to ensure the long-term viability of this resource.
Keywords: Ethiopia, MODFLOW, groundwater recharge, hormat-golina, wetspass
