Need for a Multi-Sensor Monitoring Approach for Embankment Failures: Lessons Learned from the Edenville Dam Failure

The Edenville Dam, an earthen embankment in Midland, MI, failed on May 19, 2020, after 3 days of elevated rainfall (3.83–8.0 in.; 9.7–20 cm), which caused flooding downstream of the dam. Dam infrastructure similar to that at the Edenville Dam is not uncommon in the United States and hence requires periodic monitoring. A pre-failure analysis was conducted in the dam to explore the application of remote sensing in dam monitoring. Persistent scatterer interferometry (PSI), a form of synthetic aperture radar (SAR) interferometry, was used to analyze 97 Sentinel-1 images to measure the line-of-sight (LOS) displacement prior to the failure. The PSI analysis showed hardly any signs of deformation at the failure location and implied stable embankments with velocities ranging from 3.1 to −5.4 mm/yr. The soil moisture index (SMI) derived using 14 Landsat-8 images between 2016 and 2020 suggested the presence of subsurface seepage and a potential failure zone. This study illustrates the requirement for multi-sensor remote sensing–based approaches for continuous dam monitoring and analysis.