Exploring the Linkage between Urban Flood Risk and Spatial Patterns in Small Urbanized Catchments of Beijing, China

Abstract

In the context of global urbanization, urban flood risk in many cities has become a serious environmental issue, threatening the health of residents and the environment. A number of hydrological studies have linked urban flooding issues closely to the spectrum of spatial patterns of urbanization, but relatively little attention has been given to small-scale catchments within the realm of urban systems. This study aims to explore the hydrological effects of small-scaled urbanized catchments assigned with various landscape patterns. Twelve typical residential catchments in Beijing were selected as the study areas. Total Impervious Area (TIA), Directly Connected Impervious Area (DCIA), and a drainage index were used as the catchment spatial metrics. Three scenarios were designed as different spatial arrangement of catchment imperviousness. Runoff variables including total and peak runoff depth (Qt and Qp) were simulated by using Strom Water Management Model (SWMM). The relationship between catchment spatial patterns and runoff variables were determined, and the results demonstrated that, spatial patterns have inherent influences on flood risks in small urbanized catchments. Specifically: (1) imperviousness acts as an effective indicator in affecting both Qt and Qp; (2) reducing the number of rainwater inlets appropriately will benefit the catchment peak flow mitigation; (3) different spatial concentrations of impervious surfaces have inherent influences on Qp. These findings provide insights into the role of urban spatial patterns in driving rainfall-runoff processes in small urbanized catchments, which is essential for urban planning and flood management.

Impact of alternative land cover descriptions on urban hydrological model simulations

“…The particularly poor performance of the UA models in the low density area (Figure 4(a,d)), appeared to be linked to the significantly lower DCIA value when compared to models created with other datasets (Table 5). This is in line with earlier findings of DCIA exhibiting a strong control on urban runoff processes (Yao, Chen, and Wei 2017;Lee and Heaney 2003). DCIA also explained the differences between the alternative datasets for the smaller event in the medium density site (Figure 4(e)).…”

“…While having access to such data facilitates spatial parametrization of urban hydrological models, it remains uncertain how the results compare against models constructed using manually collated information from maps, aerial photographs and site visits. In addition, earlier research has highlighted the importance of impervious areas and directly connected impervious areas in controlling the runoff response in urban areas (Lee and Heaney 2003;Yao, Chen, and Wei 2017). These characteristics are likely to vary between different land cover datasets.…”

Conceptual Planning of Urban–Rural Green Space from a Multidimensional Perspective: A Case Study of Zhengzhou, China

“…Natural features of rivers have been lost [57], and the purifying functions of rivers have declined [57], among other issues [58,59]. This may be the causes of severe urban flooding and waterlogging in Beijing [60,61], Wuhan, and other large cities in China [62]. Watershed management and river ecological restoration are important for the sustainable development of human settlements [63].…”

Analysis of the Effects of the River Network Structure and Urbanization on Waterlogging in High-Density Urban Areas—A Case Study of the Pudong New Area in Shanghai

“…Rapid urbanization increases the area of impervious surfaces, a major factor that affects urban hydrologic processes through increased surface runoff volume, increased runoff velocity, decreased time of concentration and decreased groundwater recharge [1,2,3,4]. The generation of excess direct runoff and increasing urban flooding occurs as a result of changes to the urban microhydrological process and the insufficient capacity of urban drainage systems.…”