Day 4

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Paper title Ground deformation analysis for a sustainable groundwater abstraction management using InSAR techniques
Authors
  1. Fabian Stoffner Federal Institute for Geosciences and Natural Resources (BGR) Speaker
Form of presentation Poster
Topics
  • A7. Hydrology and Water Cycle
    • A7.05 InSAR for the groundwater management
Abstract text In semi-arid regions characterized by large agricultural activities, a high volume of water is needed to cover the water requirements for agricultural production. Due to low precipitation and the associated limited availability of surface water, aquifers often represent the main source of irrigation water in these regions. Mostly, the information about the abstraction of the groundwater resources and its management are not well investigated because of technical and financial restrictions. Thus, there is a high demand and need for improved and sustainable monitoring approaches.
Over the past decades, remote sensing has been established as an effective and powerful tool to monitor the planet’s surface. The Copernicus Program of the European Commission (EC) in partnership with the European Space Agency (ESA) offers strong possibilities in satellite based monitoring using remote sensing techniques. Since the first Sentinel mission has been launched in 2014, a solid database of satellite imagery with a high temporal resolution has been made available for everyone based on a free and open data policy. Particularly, Interferometric Synthetic Aperture RADAR (InSAR) techniques have gained a higher focus for groundwater management and may help to assess reliable information on the subsurface.
In this study in the framework of German-Moroccan international cooperation, the Chtouka region with its eponymous aquifer in South Morocco has been chosen. It represents a region with great importance for the export of agricultural products and the national trade balance and, therefore, depends on an anticipatory sustainable ground water management. In addition, high groundwater abstraction rates significantly change the flow dynamics of this coastal aquifer and lead to increased saltwater intrusion deteriorating the groundwater quality in the long term.
Sentinel 1 C-band data has been used in order to measure the ground displacement and the velocities over the past six years. Two smaller areas in the Chtouka region has been identified where interferometric analysis based ground deformation maps and available piezometric head measurements are investigated. Based on these observations, a correlation can be made between the ground motion and the change in groundwater level. The results can improve a sustainable groundwater management by directly quantifying the groundwater abstraction where in-situ data is insufficient and by filling gaps in monitoring data. In addition, simulations can be run to simulate future ground motions to support the regulation of the groundwater abstraction for agricultural purposes.