Groundwater is a precious natural resource of limited extent. In order to ensure its judicious use,proper evaluation is required. Evaluation of groundwater involves several factors of which,Groundwater flow and recharge is paramount. Modeling of flow system and quantification of the recharge rate is a prerequisite for efficient and sustainable management of groundwater. This book is mainly concerned with estimation of spatially distributed natural recharge using WetSpass model and modeling groundwater flow system of Wukro basin, Northern Ethiopia.