Monitoring Flood Dynamics in 2022 in the North River Basin (China)

Heavy rainfall and flooding are China's most frequent natural disasters. In 2022, the North River Basin experienced three large regional floods, the highest frequency since 1949. Previous studies using sparse hydrological stations lacked comprehensive flood inundation data. This study employs 31 scenes of Sentinel-1 SAR imagery from June 2 to July 17, 2022, to monitor flood inundation in the North River Basin (NRB). The results indicate: (1) From June 2 to June 27, the flood inundation area was 2134.30 km(2), with 814.12 km(2) of farmland affected, accounting for 38.2% of the total. From June 28 to July 17, the inundation area was reduced to 1407.68 km(2), with 529.39 km(2) of farmland affected, comprising 37.7% of the total. (2) The flood area decreased by 726.32 km(2) between the two periods, with significant reductions in the upstream regions. The slowest recession was along the Pajiang River, influenced by Feilaixia Dam's flood discharge and typhoon rains. This study's methodology guides dynamic flood area monitoring and offers valuable insights for post-flood assessment and flood control in the North River Basin.