Study on the effect of soil permeability changes on the process of urban storm waterlogging during heavy rainfalls: A case study of Nanguan District, Changchun City

Abstract

[Objective] With the goal of mitigating or inhibiting the severity of urban storm waterlogging, the inhibitory effect of soil permeability changes on urban storm waterlogging is studied. [Methods] Hydrological and hydrodynamic methods, infiltration coefficient calculation, and scenario setting were used to comprehensively construct the urban rainstorm waterlogging numerical model and infiltration volume model. The effects of different levels of vegetation coverage on factors such as depth, area, volume, and duration of waterlogging on the urban subsurface were investigated. [Results] The results showed that: in terms of waterlogging water depth, in Scenario 1, the maximum and minimum water depths were 1.30 m and 0.10 m, respectively. In Scenario 2, the maximum and minimum water depths were 0.95 m and 0.05 m, respectively. In Scenario 3, the maximum and minimum water depths were 0.35 m and 0.01 m, respectively. As for waterlogged area, the areas in Scenario 1, Scenario 2, and Scenario 3 were 28.96 km², 14.40 km², and 4.16 km², respectively. In terms of water volume, the reduction rate of water volume in the study area decreased as the rainfall intensity increased, and the difference decreased with the increase in rainfall intensity. In terms of water level in the study area, the maximum water level decreased due to the increase of vegetation coverage, with the reduction rate fluctuating between 5% and 20%, but the overall change was minor. In terms of waterlogging delay time in the study area, the time difference for the maximum average water level in Scenario 1 and Scenario 3 were 60 minutes. [Conclusion] Increasing urban vegetation coverage can effectively mitigate the severity of urban storm waterlogging. The results of this study not only serve as a reference for the rational planning of urban green spaces, but also provide a decision-making basis for the government emergency departments in their disaster response efforts.

Keywords

waterlogging disaster / inhibitory effect / vegetation coverage / soil permeability / numerical simulation / rainfall