Chinese Satellite-Based Flood Mapping and Damage Assessment in Dongdian Flood Detention Basin, China

Against the background of rapid climate warming, frequent and severe flooding disasters significantly impact socio-economic development and human life. In 2023, due to the northward movement of Typhoon Doksuri, extreme precipitation occurred in northern China, which resulted in a massive flood event in the Haihe River basin. Seven flood detention basins (FDBs) in North China were successfully implemented to effectively alleviate the downstream flood pressure. Leveraging all available Chinese satellite data, we monitored the flooding process daily, focusing on reviewing the flooding in the Dongdian FDB. The results indicate that since the activation of Dongdian FDB on August 1, the flood reached the urban area of Tianjin in just nine days and inundated the entire detention basin. Flooding persisted in the detention basin for about a week before gradually receding. The total maximum inundated area in the whole region was 307.5 km2, including 240.5 km2 of arable land, 7.0 km2 of greenhouse land, and 9.7 km2 of built-up land, with an average inundation duration of 19 days. The total cumulative inundated arable land area was 240.5 km2, with an average inundation time of 21 days. This study shows that multi-source Chinese satellite data can provide comprehensive information and adequate references for post-disaster assessments.