The book focuses on water resources management in the Erbil Basin, covering both surface and groundwater modeling for its three main sub-basins: KAPRAN, CENTRAL, and BASHTEPA. It provides a comprehensive analysis of groundwater flow using three-dimensional modeling techniques under steady-state and transient, heterogeneous, and isotropic conditions. The study identifies key water management issues in the Erbil Basin and examines the impacts of climate change on the region. The book also discusses how climate change has altered the hydrological dynamics of the Erbil Basin, leading to the consolidation of the three original sub-basins (KAPRAN, CENTRAL, and BASHTEPA) into two newly defined basins, named Jwan Basin and Jwan S. Basin. This reconfiguration reflects the significant impact of climate change on the water flow and distribution in the region, which the author evaluates using advanced modeling tools such as GIS, MODFLOW, and AQUAVEO softwares.