Hydrogeological Criteria to Improve the Sponge City Strategy of China

Abstract

China is facing frequent waterlogging and an increasing water scarcity that mirrors the fast urban and economic expansion of the last 4 decades. To mitigate these issues, the government promulgated the “Sponge City” strategy; a concept rooted in practices in western countries aimed at collecting and reusing 65–90% of urban rainfall. The application consists of absorbent infrastructures such as green roofs and rain gardens combined with the pre-existing urban environment. However, due to climate heterogeneities and the different urbanization contexts in China, these goals may seem overly ambitious in many areas of the country. Compact urbanization, together with heavy rainfall concentrated in short events, puts dramatic stresses on these infrastructures. At the same time, overdesigned infrastructures are expensive and may not be practical to retrofit in existing urban areas. In this paper, the role of urban aquifers as natural Sponge City elements are investigated throughout China. The method of implementation is inexpensive and easy to apply, favoring the direct infiltration to the subsoil after the conversion of the urban surfaces from impervious to permeable. Infiltration to urban aquifers alleviates the pressure on sewers, urban streams, as well as waste-water treatment plants. Considering urban aquifers with different hydraulic characteristics, water table dynamics after large infiltration events from rainfall are simulated via numerical analysis. Hydrogeological and geomorphological analyses are carried out to individuate criteria for the mapping of high absorbance areas at the regional and local scales. A Sponge City approach involving the urban aquifers can represent a winning formula for the success of this ambitious but compelling plan.

The Role of Aquifers in Sustaining the Sponge City Concept in Chinese High-Density Housing

“…In particular, the connection between the geomorphological and hydrogeological settings remains the driving factor in determining the regional absorbance potential. In accordance with the conceptual model proposed for the hilly terrains of Shenzhen via direct geomorphological and hydrogeological data [23] and major Chinese megacities [24], a conceptual model is proposed to characterize the urban areas. From the mountain sectors to the coastline, each geomorphological sector has unique characteristics of its own:…”

“…Ref. [24] suggests the potential absorbance of many Chinese megacities based on groundwater data and geomorphological evidence. However, regional scale analysis is necessary as the application of these practices is of wide interest, especially in smaller cities characterized by less funding.…”

What makes a successful Sponge City project? Expert perceptions of critical factors in integrated urban water management in the Asia-Pacific

“…As a result, we decided to evaluate the satisfaction of professionals in China, in Australia and across both of these Asia Pacific based cultures too. We considered that such an approach could provide insight into locally significant success factors (Jin et al, 2021) and also Asia-Pacific significant success factors.…”

Rapid Urbanization Increased the Risk of Agricultural Waterlogging in the Huaibei Plain, China

“…The control of waterlogged arable land has drawn great attention from governments, researchers, and food producers. The drainage engineering of farmland and the sponge city strategy are the main components of waterlogging control work measures [11,12]. The study of farmland drainage engineering and design parameters is crucial for controlling waterlogging in agricultural regions.…”