SAR-based dynamic information retrieving of the Beijing-Tianjin-Hebei flood-inundation happened in July 2023, North China

Abstract

Climate change-induced rainfalls have elevated the likelihood of flood occurrences, disrupting severely the normal functioning of people. Especially in the geographically unique Beijing-Tianjin-Hebei (BTH) plain in north China, an unanticipated sudden and long-duration flood-inundation happened in the summer of 2023 (referred to as the ‘23.7’ BTH flood). To address the dynamic information and recreate the flood evolution, we constructed a flood retrieving and analysis procedure to elucidate the development process and its impacts. First, accurately extract the temporal inundation extent of floods. Subsequently, we implemented the selected knowledge-driven algorithm to retrieve the dynamic information of flood evolution, including inundation extent, water depth, and shortest inundation duration. Furthermore, hazard-bearing bodies like cultivated land, population, and buildings were analyzed to improve our understanding of the flood impact. We uncovered that the ‘23.7’ BTH flood had caused extensive inundation and notably affected the Daqing River System, where the flood breached the river bank and submerged both buildings (0.96 km2) and cultivated land (241.46 km2), and led to prolonged inundation in the Baiyangdian area, which persisted for up to 30 days. This disastrous event highlights the great requirements to boost upstream flood storage capacity and enhance preparedness and rapid response capabilities for abnormal floods.

Keywords

• Beijing-Tianjin-Hebei plain
• SAR image
• flood evolution
• water depth
• shortest inundation duration