Int. J. Global Environmental Issues, Vol. 16, Nos. 1/2/3, 2017 17 Copyright © 2017 Inderscience Enterprises Ltd. Evaluation and assessment of water budget in the eastern aquifer basin of the West Bank, Palestine Fadi Dweik* Applied Research Institute, Jerusalem, Palestine Email: fdweik@arij.org *Corresponding author Mahmoud Rahil Palestine Technical University, Kadoorie, Palestine Email: mrahail@yahoo.com Mhd. Suhyb Salama University of Twente/ITC, The Netherlands Email: s.salama@utwente.nl Abstract: The study is mainly intended to assess and evaluate the water budget in the eastern basin at 1 km resolution, through a comprehensive model of the eastern aquifer by estimating the evapotranspiration (evaporation and transpiration), surface runoff and groundwater recharge in the targeted aquifer for the period (1950–2000). A spatial modelling approach and geographical information systems (ArcGIS) specialist was used to evaluate and estimate the water budget for the 50 years period (1950–2000). Hydro-meteorological data for the 50 years period were used to drive precipitation, reference evapotranspiration, evapotranspiration, runoff spatial grids, and ground water recharge along with an summed minor losses were integrated by GIS spatial interpolation. The results of this study show that the average annual ground water recharge for the 50 years period in the study area is almost 200 millions of cubic metres (MCM) per year. A variation was found in the recharge values from the eastern slopes till the central highlands in the West Bank, this variation is due to the variation in temperature and precipitation in the targeted area. Keywords: water budget; eastern aquifer; West Bank; Palestine. Reference to this paper should be made as follows: Dweik, F., Rahil, M. and Salama, M.S. (2017) ‘Evaluation and assessment of water budget in the eastern aquifer basin of the West Bank, Palestine’, Int. J. Global Environmental Issues, Vol. 16, Nos. 1/2/3, pp.17–28. Biographical notes: Fadi Dweik is a Research Associate at the Water and Environment Research Department at ARIJ. His main responsibilities at ARIJ include conducting scientific researches and writing project proposals, scientific papers and project reporting, proposals on GIS and remote sensing.