Assessing the impact of river changes on flood regulation capacity using a coupled flood model in an urbanized plain river network region

• Published in: Journal of hydrology. Regional studies Vol. 55; p. 101925
• Main Authors: Wang, Yuefeng, Lei, Chaogui, Ye, Sheng, Wang, Qiang, Xu, Yu, Zhang, Junyi, Xu, Youpeng
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-10-2024; Elsevier
• Subjects: Coupled flood model; Flood event; Flood regulation capacity; River system; Flood regulation capacity; Coupled flood model; River system; Flood event
• ISSN: 2214-5818; 2214-5818
• DOI: 10.1016/j.ejrh.2024.101925

The Changzhou Plain, the Taihu Lake Basin, Eastern China.
This study introduces an event-based approach for assessing the impact of river changes on flood regulation capacity in urbanized plain river network regions for the first time. The Changzhou Plain, river length decreasing by 7.55 %, was taken as an example to assess the effects of river changes on its flood regulation capacity from the 1980s to the 2020 s.
Two key indices, flood storage capacity (FSC) and remaining flood storage capacity (RFSC), were developed and calculated using a coupled flood model. Both the coefficient of determination (R2) and the Nash–Sutcliffe efficiency (NSE) exceeded 0.90 during model calibration and validation. The Changzhou Plain experienced river degradation from the 1980s to the 2020 s, with 11.14 % reduction in tributary river length and 3.05 % increase in main river length, leading to decreased water surface area and enhanced connectivity among main rivers. Regional FSC and RFSC increased by 8.42 % and 1.97 %, respectively, due to improved connectivity of main rivers from the 1980s to the 2020 s. The reduction in tributary rivers had minimal effects on FSC (increase of 1.62 %) and RFSC (decrease of 1.74 %), while improved connectivity of main rivers contributed to significant increases in both FSC (6.70 %) and RFSC (3.74 %). These findings underscore the effectiveness of enhancing river connectivity as a strategy to bolster flood prevention in the Taihu Plain, offering valuable insights for flood management and river planning.
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•A new approach was proposed to assess the flood regulation capacity of rivers in urbanized plain river network region.•First time to assess flood regulation capacity of rivers at flood event scale based on coupled flood model.•The effect on flood regulation capacity from main river changes was higher than that from tributary river changes.•Novel theoretical grounds for flood management and river planning.