Urban public green space (UPGS) plays an important role in sustainable development. In China, the planning, classification, and management of green spaces are based on the Standard for Classification of Urban Green Space (SCUGS). However, limitations to the UPGS exist due to the over-emphasis on quantitative standards and insufficient consideration of the actual access mode of residents. Though the taxi trajectory data are widely selected to study public service facilities, its adoption in UPGSs research remains limited. Based on the case of UPGSs in the three districts of Shenzhen, we used the taxi (including cruise taxis and Didi cars, which are like Uber) trajectory data to investigate the spatial layout and the allocation of management resource of the UPGSs from the spatial interaction perspective. By rasterizing and visualizing the percentage of pick-up and drop-off points in the UPGSs’ buffer, the service scope of UPGSs was defined, which reflected the spatial distribution and activity intensity of the visitors. Then, an unsupervised classification method was introduced to reclassify the twenty two municipal parks in the three districts. Compared to the traditional planning method, the results show that the service scope of the same type of UPGS in the traditional classification is not the same as the one obtained by the study. Visitors to all UPGSs are distributed as a quadratic function and decay as the distance increases. In addition, the attenuation rates of the same type of UPGSs are similar. The findings of this study are expected to assist planners in improving the spatial layout of UPGSs and optimizing the allocation of UPGS management resources based on new classifications.

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.

Chinese cities and megacities occupy large areas with high population densities. These urban sectors have extensive impervious surfaces and import large amounts of water from pristine sources, putting pressure on the urban drainage systems during storms. To reduce flood risk and tackle water scarcity, the Chinese government promulgated the Sponge City concept: an ensemble of absorbing features, including permeable pavements and green roofs, to reduce urban runoff and increase water storage. We evaluate the benefits of merging the urban aquifer with conventional Sponge City features by simulating stormwater storage in aquifers with a groundwater model (MODFLOW) and a stormwater management model (SWMM). The urban aquifers of an ideal district, characterized by high-density housing and a flat morphology, collect and dissipate extreme rains (200 mm in 6 h) when the hydraulic conductivity of the subsoil is higher than 1·10−5 m/s, roughly corresponding to a medium productive aquifer. Economic and ecological benefits at the catchment scale are also discussed. Suitable shallow aquifers are individuated and discussed throughout China via a hydrogeological and geomorphological approach. The proposed method increases the percentage of water that can be controlled above that obtained through conventional Sponge City features.