Groundwater, armed conflict, and land surface uplift: an InSAR analysis of the Orontes River Basin

Abstract

Armed conflicts have a pronounced impact on the environment, leading to changes in land use/land cover (LULC) and water resources. The Orontes River Basin (ORB), which covers parts of Lebanon, Syria, and Turkey, represents a unique case study.  After a prolonged period of intensive groundwater abstraction in the ORB, the Syrian War has led to cropland abandonment in certain areas, whereas continued intensive agriculture persisted in others. Groundwater levels are expected to have recovered due to conflict-related LULC changes and, consequentially, reduced irrigation demands. However, direct observation of this recovery is impeded due the near-complete lack of traditional hydrological or hydrogeological data in the Syrian portion of the ORB.Just as overexploitation of groundwater can result in land subsidence, groundwater recovery may manifest itself as land surface uplift, given suitable poro-elastic properties of the subsurface hydrogeological units. In order to infer regional groundwater dynamics across the ORB, we use interferometric synthetic aperture radar (InSAR) to detect land uplift and subsidence. Our results show complex transient, non-uniform trends in subsidence/uplift due to conflict-induced changes to LULC and groundwater exploitation across the ORB. The results of this study can be used for optimizing humanitarian aid and as model inputs for future hydrological models in areas where in-situ measurements are almost non-existent.