Study on the calculation method of water demand threshold for ecological restoration of typical urban rivers

Abstract

[Objective] This study aims to investigate the role of sponge cities in mitigating urban waterlogging by selecting the Jincun development area of Jincheng City as a research area and analyzing the regulation effects of low impact development(LID) facilities on runoff and waterlogging at different spatial scales. [Methods] A coupled urban stormwater and waterlogging model was developed by integrating the Storm Water Management Model(SWMM) and the two-dimensional module of InfoWorks ICM. The model simulated various storm scenarios and LID layout schemes to analyze rainfall-runoff processes and waterlogging characteristics in plots, drainage zones, and regions. [Results] The findings indicated that LID facilities effectively reduced runoff peak values, decreased total runoff, accelerated runoff recession, and mitigated overflow nodes and overloaded pipe segments. They also significantly reduced areas affected by waterlogging and lowered water depths. The regulation effect of LID facilities showed minor variation across different spatial scales and performed well within a 1 to 5-year recurrence period. Specifically, under 1-year recurrence period rainfall, the largest LID layout scheme reduced surface runoff by more than 75%. [Conclusion] LID facilities demonstrate strong efficacy for short-recurrence-period storms but have limited capacity for long-recurrence-period waterlogging control, particularly at severe waterlogging points. Expanding the scale of LID facilities can substantially enhance their runoff regulation capacity.

Keywords

water ecological environment / ecological water demand / urban rivers / flow threshold / Lutang Branch Canal / comprehensive determination method / runoff / water resources