Displacement monitoring at Svartevatn dam with interferometric SAR

In Norway, deformation monitoring of dams is regulated by law; traditionally it is done by geodetic measurements [1]. To ensure early recognition of problem areas at the dam and/or at the slopes around the reservoir, frequent deformation measurements are necessary. Here, we investigate the feasibility of applying satellite based SAR interferometry to monitor deformations at dams and reservoir slopes. We present results of an InSAR study at Svartevatn dam in south west Norway, an earth-rockfill dam. Two ERS image stacks have been acquired in ascending and descending mode, respectively. Each image stack has been processed with the Small Baseline Subset (SBAS) to generate deformation maps. The results show that historic SAR data can be used to monitor deformations at the dam with a resolution comparable to geodetic measurements.