Effect of Land Use\Land Cover Changes on Estimated Potential Runoff in the Nablus Mountains Watersheds of Palestine: A Case Study

Abstract

Freshwater is a major concern in arid and semi-arid regions of the West Bank due to political conditions where the Israeli occupation controls the groundwater resources and physical drivers such as land use/land cover (LULC) changes. The Nablus Mountains region receives between 175 and 739.1 mm of annual rainfall. Hence, direct runoff is high and untapped because of surface and rainfall characteristics. This study is aimed to identify the spatial distribution of LULC changes and its impact on potential rainfall–runoff water at the sub-watershed scale for eleven main watersheds in the Nablus Mountains. Remote sensing data (Landsat 5, 7, and 8 images from 1984, 2000, and 2016, respectively) were employed to detect and measure LULC changes. Geographic information systems (GIS) and soil conservation service curve number (SCS-CN) methods were employed to calculate the potential runoff of 487 rainy days (2008–2018). Seven LULC classes were identified using the supervised classification method in GIS (10.5). The findings of this study revealed an increase of 116%, 22%, and 8% in urban areas, bare lands, and agriculture areas, respectively, and a decrease of 14% and 22% in pastures areas, and forests, respectively, between 1984 and 2016. Furthermore, there was a significant increase of 5.8% in the potential annual runoff between 1984 and 2016 due to LULC changes which is around 7.8 M3M. The runoff estimation model indicated that the upstream sub-watersheds of Qana, Dair-Balout, and Zoumar watersheds are highly suitable locations for rainwater harvesting and flash floods mitigating projects.