The Geodetic Institute Karlsruhe participated in the international research project DAMAST (Dams And Induced Seismicity Technologies For Risk Reduction—Technologies for the Safe and Efficient Operation of Water Reservoirs). The project was part of the Client II funding program—International Partnerships for Sustainable Innovations - within the FONA³ (Research for Sustainable Development) framework program of the Federal Ministry of Education and Research (BMBF). DAMAST was subsequently continued in the projects DAMAST-Addon and DAMAST-Transfer—Transfer for Sustainability, also funded by the BMBF.
The geodetic investigations focus on the 270-meter-high and 750-meter-long Enguri Dam in the Caucasus Mountains in Georgia. The adjacent Enguri Reservoir and the surrounding area are also the subject of the investigations. The safety of the dam—and thus also that of the local population - is threatened by a variety of factors, such as earthquakes and landslides. As part of the project, safety-related parameters are to be assessed both qualitatively and quantitatively.
The geodetic approach to monitor the Enguri Dam and its reservoir integrates Global Satellite Navigation Systems (GNSS) and satellite-based Synthetic Aperture Radar imagery (SAR) to quantify both structural deformation as well as regional displacements that might force the dam. A network comprising ten GNSS stations and six radar reflectors was established on the dam and along the neighboring Ingirishi Fault providing millimeter-level accuracy for 3D displacement monitoring with high temporal resolution. Complementing this, Persistent Scatterers (PS) as obtained from an interferometric processing of SAR images (PS-InSAR) data elucidate surface movement patterns at the dam and its surrounding areas. Analysis of GNSS processing results reveal that displacement trajectories of the dam’s stations form a hysteresis loop, predominantly lying in the vertical plane. The maximum observed displacements reach up to 8.5 cm in the horizontal direction and 3 cm in the vertical direction. Through the application of the Hydrostatic-Season-Time model, hydrostatic and seasonal motion components are disentangled, demonstrating that vertical displacements are primarily driven by seasonal effects.