Dam Monitoring with Ground Motion Services – A Case Study of a Gravity Dam with the German Ground Motion Service

Kurzfassung

Dams are traditionally monitored by in-situ geodetic measurements, such as pendulum, trigonometry, and GNSS. However, due to factors like topography and practicability, many dams are only monitored by trigonometric measurements, which are carried out only once or twice a year, due to high cost and time investment. Persistent Scatterer Interferometry (PSI) offers the possibility of monitoring such infrastructures at more regular intervals. In particular, existing ground motion services relying on the PSI technique provide deformation time series for long time intervals, allowing for trend and anomaly detection in the deformation patterns. This study presents a first assessment of the German Ground Motion Service (BBD) for the monitoring of a gravity dam in the Free State of Thuringia, Germany. Despite the suboptimal dam orientation for the PSI technique, BBD data exhibits good agreement with in-situ measurements (achieving R² values above 0.5 and up to 0.8 for the descending direction). These results confirm the utility of such services for infrastructure monitoring. However, it is imperative to account for dam orientation and the update frequency of these services in operational practices.