Sentinel-1-Based Analysis of the 2024 Tuanzhouyuan Dike Breach Disaster in Dongting Lake and Regional Risk Assessment

This study systematically investigates the 2024 dike breach event in Tuanzhouyuan, Dongting Lake, China, using synthetic aperture radar (SAR) remote sensing technology. By integrating Sentinel-1 SAR-based water body extraction and small baseline subset interferometric SAR deformation monitoring techniques, we reveal the disaster mechanism resulting from the combined effects of extreme hydrological events and structural defects of the dike system. The results demonstrate that the average prebreach water surface area was 5.87 km<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>, which peaked at 47.46 km<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> postdisaster, causing significant damage to the local area. Deformation monitoring identified certain dike sections with annual deformation exceeding 60 mm, with the breach section showing abnormal pre-event deformation characteristics, including reverse displacement patterns, indicating substantial safety risks. Hydrological analysis shows the water level during the 2024 flood season rose at an average daily rate of 0.50 m, 1.8 times higher than normal years, leading to seepage failure of the dike foundation. Through a comprehensive analysis of inundation extent, deformation monitoring, and hydrological conditions, this study provides a novel approach for disaster early warning and risk assessment in similar regions, offering both theoretical significance and practical value.