Dynamic Trends of Urban Flooding Mitigation Services in Shenzhen, China

Abstract

Urbanization is characterized by population agglomeration and the expansion of impervious land surfaces. As a result of ongoing urbanization, rain and flood events have increasingly affected the well-being of residents in cities across the world. This should draw attention to the role of urban ecosystems in providing runoff retention/flood mitigation services. Focusing on Shenzhen, a major city in southern China, we used a hydrologic model based on the Soil Conservation Service curve number (SCS-CN) model to evaluate this flood reduction ecosystem service and its dynamic trends based on long-term remote sensing data from 1980 to 2018. We find that Shenzhen’s capacity for flood reduction gradually decreased due to changes in land use. The spatial distribution showed strong reduction capacity in the eastern part of the city and weak capacity in the western part. Additionally, the city’s total flood reduction capacity decreased by over 1.88 × 108 m3 over the past two decades. This loss of ecosystem-based flood reduction capacity undermines Shenzhen’s resilience against extreme weather events. Due to climate change, Shenzhen should advance its plan to build a “Sponge City” rooted in the conservation, restoration, and construction of urban ecological spaces.

Driving Forces on the Distribution of Urban Ecosystem’s Non-Point Pollution Reduction Service

“…Shenzhen, an important city along China's southern coast, is in the southern region of the Guangdong Province and on the east coast of the Pearl River Estuary, as shown in Figure 1. As one of the four central cities in the Guangdong-Hong Kong-Macao Greater Bay Area, Shenzhen was the first city in China to undergo reform and open up [36]. The city has a land area of 1997.47 km 2 [36], of which 1005.95 km 2 is built-up land, and has a year-end resident population of 17,681,600 (as of the end of 2021).…”

“…As one of the four central cities in the Guangdong-Hong Kong-Macao Greater Bay Area, Shenzhen was the first city in China to undergo reform and open up [36]. The city has a land area of 1997.47 km 2 [36], of which 1005.95 km 2 is built-up land, and has a year-end resident population of 17,681,600 (as of the end of 2021). In the context of continuous industrial development and transformation, the local soil environment has gradually deteriorated with the influx of population and the continuous reduction of nonecological space land; it has more-serious environmental problems, such as soil hardening and slabbing, soil acidification, soil salinization, and soil pollution [37,38]; and the supply base of ecosystem services has been challenged.…”

Water Dams of the Krakow Fortress: Potential of a Vanishing Heritage

“…Creating waterabsorbing areas is therefore a priority that is extensively noted in the city's development strategies. Furthermore, these measures should account for the proper distribution of retention areas and thus improve their effectiveness [36], reduce the intensity of water surges [37,38], and enhance biodiversity in floodplains [39,40].…”

Urban Flooding Mitigation Techniques: A Systematic Review and Future Studies

“…Most of rainwater reaching the ground surface either infiltrates the soil or returns to the air by evaporation and evapotranspiration. Urbanization has sealed natural soils by pavements, roofs, and other impervious surfaces, constraining natural infiltration and evapotranspiration and converting rainfall into runoff [1,2]. Runoff from open soils in urbanized areas is also increasing because construction activities have compacted soils to behave like impermeable surfaces [3,4].…”