IAH 50th Worldwide Groundwater Congress, Cape-Town, South Africa, 18 - 22 September 2023, pp.1
This paper presents the results of groundwater flow modeling studies that were conducted within the scope of the PRIMA RESERVOIR project. The main goal of the project is to develop an innovative methodology to mitigate land subsidence due to excessive groundwater exploitation in water-stressed Mediterranean watersheds. This objective is achieved by integrating earth-observation derived land subsidence rates with a coupled implementation of numerical groundwater flow and geomechanical modeling. MODFLOW-based 3-D transient flow models were constructed for the four pilot sites (the coastland of Comacchio in Italy, the Alto Guadalentín aquifer in Spain, the Gediz River basin alluvial aquifer in Turkiye and the Azraq basin in Jordan) that have different hydrogeological properties and pose different challenges concerning water management. Models were calibrated and run for similar simulation periods (2013-2021) to obtain hydraulic head drawdowns and change in groundwater storage. Land subsidence at these sites were evaluated using Advanced Differential Radar Interferometry (A-DInSAR) on image stacks from the Sentinel-1 satellite. Subsidence rates were then compared to rates of hydraulic head drawdown to identify areas of groundwater pumping induced subsidence. The comparison for all study areas suggested that locations of maximum displacements do not necessarily coincide with areas that display the largest head drawdown as calculated by the flow models. Other triggering factors such as the thickness of compressible materials are also related to high subsidence areas.