The influence of change in river networks on waterway connectivity and flooding processes

Abstract

Urbanization disrupts river networks, alters waterway connectivity, and elevates flood control pressure. Quantitatively assessing river network changes and its impact on waterway connectivity and flooding processes is imperative. This study constructed a waterway connectivity evaluation model and a hydrologic-hydrodynamic model to assess the river network, the waterway connectivity and the flooding change in the Qinhuai River Basin, and used scenario analysis to get the effectiveness of different topology changes. The results showed a 0.09 decline in connectivity from 2000 to 2010, which led to a 1-hour earlier peak occurrence time, a 2.59 m3/s increase in peak discharge and a 51 mm rise in peak water level. Scenario analysis demonstrated that adding tributaries can enhance both connectivity and flood resilience. Increasing river width effectively reduces peak water levels while minimally affecting connectivity. However, extending river length has a negligible effect on peak water levels but may decrease waterway connectivity.