Coastal Dryland Subsidence Detection Using Interferometric Synthetic Aperture Radar (InSAR)

The Middle East and North Africa (MENA) region is representative of the most water scarce region in the world. Due to rapid population growth, climatic regime affects, and increased anthropogenic activity, the water resource demand exceeds the sustainable supply. The Souss-Massa Basin in Morocco has experienced extensive groundwater abstraction causing accelerated subsidence rates. The primary groundwater aquifer, Plio-Quaternary Plain Aquifer, is pumped by over 20,000 wells at a rate of 650 MCM/yr., exceeding the rate of recharge by 260 MCM/year. Due to the climate regime effects occurring, resulting in the decrease of groundwater resources, land subsidence has taken place. Interferometric Synthetic Aperture Radar (InSAR) offers the opportunity to observe landscape changes from archived synthetic aperture radar data. This radar technique provides effective observations for measuring movements (mm to cm) that cover a given area. Using InSAR data acquired from the European Space Agency, the Souss-Massa Basin was analyzed to identify how the over-exploitation of groundwater resources influence landscape changes that impact groundwater dynamics. Preliminary results suggest 0-20 mm/yr. of subsidence occurred during 2003 to 2010. As these results detail the landscape changes occurring in the Souss-Massa Basin, additional analysis and methods are still ongoing to understand its impact on the groundwater dynamics of the Plio-Quaternary Plain Aquifer. Understanding the effects of the over-abstraction of groundwater will provide valuable advisement in the sustainability, regulation, and policy of the economic state of Morocco. This analysis provides applicability to other MENA regions facing similar water resource demands to provide the opportunity for better water resource management. As the demand for water resources is expected to increase, this coupled remote sensing and field-based approach will enhance our understanding of the landscape changes occurring to better meet the water resource demand.