The Effect of Sponge City Construction for Reducing Directly Connected Impervious Areas on Hydrological Responses at the Urban Catchment Scale

Changmei Liang,Xiang Zhang,Jing Xu,Dunxian She,Jun Xia

doi:10.3390/w12041163

Abstract

Low-impact development (LID) has been widely used at both site-specific and local scales to try and mitigate the impact of urban stormwater runoff caused by increasing impervious urban areas. Recently, the concept of a “sponge city” was proposed by the Chinese government, which includes LID controls at the source, a pipe drainage system midway, and a drainage system for excess stormwater at the terminal. There is a need to evaluate the effectiveness of sponge city construction at the large urban catchment scale, particularly with different spatial distributions of LIDs that reduce directly connected impervious areas (DCIAs). In this paper, the performances of five design scenarios with different spatial distributions but same sizes of LID controls at the urban catchment scale were analyzed using a geographic information system (GIS) of the United States Environmental Systems Research Institute (ESRI)—based Storm Water Management Model (SWMM) of the United States Environmental Protection Agency (USEPA) and MIKE 11 of Danish Hydraulic Institute (DHI) in Xining City, China. Results confirmed the effectiveness of sponge city construction in reducing the urban stormwater runoff. The hydrological performance reduction was positively correlated and linearly dependent on DCIA reduction. Peak flow reduction was most sensitive to DCIA reduction, followed by runoff volume and peak time. As rainfall intensity increased, the hydrological performance was more sensitive to rainfall intensity than DCIA reduction. Results of this study provide new insights for stormwater managers to implement LID more effectively at the urban catchment scale.

Highlights

With rapid economic developments, global urbanization has increased continuously, especially inChina
These results show that the Storm Water Management Model (SWMM) model is suitable for simulating the hydrologic response in the study area
These results show that the SWMM model is suitable for simulating the hydrologic response in the at the monitoring cross-sections M2 and M3 were compared with the corresponding simulated water study area

Summary

Introduction

Global urbanization has increased continuously, especially inChina. Large areas of grassland and farmland were converted into roads and buildings, resulting in an increase in impervious areas These changes directly lead to changes in the previous infiltration processes, thereby altering the natural hydrological water cycle. The changes to the surface runoff characteristics of these areas include larger runoff volume, higher peak runoff, earlier peak runoff time, and poorer water quality [1,2,3,4]. Of these impacts, urban flood disasters have appeared more frequently, which increasingly threatens people’s lives and health, resulting in huge economic losses.

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Conclusion