Change of stream network connectivity and its impact on flood control

Abstract

Urbanization can alter the hydrogeomorphology of streams and rivers, change stream network structures, and reduce stream network connectivity, which leads to a decrease in the storage capacity of stream networks and aggravates flood damage. Therefore, investigation of the ways in which stream network connectivity impacts flood storage capacity and flood control in urbanized watersheds can provide significant benefits. This study developed a framework to assess stream network connectivity and its impact on flood control. First, a few connectivity indices were adopted to assess longitudinal stream network connectivity. Afterward, the static and dynamic storage capacities of stream networks were evaluated using storage capacity indices and a one-dimensional hydrodynamic model. Finally, the impact of stream network connectivity change on flood control was assessed by investigating the changes in stream network connectivity and storage capacity. This framework was applied to the Qinhuai River Basin, China, where intensive urbanization has occurred in the last few decades. The results show that stream network storage capacity is affected by stream network connectivity. Increasing stream network connectivity enhances stream network storage capacity.