Increasing urban flood risk in China over recent 40 years induced by LUCC

Land use/cover change (LUCC) caused by urbanization has a great impact on urban hydrological systems, among which urban pluvial floods are particularly prominent and have attracted worldwide attention. Although some previous studies have shown that urban LUCC increases urban pluvial flood risk and reduces urban flood regulation service (UFRS) in individual cities, there has not been a nationwide quantitative assessment in China. Here, we use a data-driven hydrological model and constructed indicators to clarify the quantitative impact of LUCC on China's UFRS and its spatial pattern from 1977 to 2018. Our analysis revealed that LUCC has caused China's UFRS to decline by 13.39%, from 31.34% in 1977 to 17.95% in 2018. Spatially, the UFRS decline in all river basins in China was greater than 10%, and the UFRS in almost all cities was decreasing. Especially in the densely distributed eastern Yangtze River basin, Pearl River basin, Southeast basin, Haihe River basin and Huai River basin, their UFSR values decreased by 11.89%, 12.17%, 12.34% and 10.81%, respectively. This is a warning that China's urban land conversion has greatly increased the urban pluvial flood risk.

Automated summary

Urbanization-induced land use/cover change has a significant impact on China's urban flood regulation service (UFRS), especially on urban pluvial floods. The study reveals that China's UFRS has declined over time and space, indicating that urbanization in China has increased the risk of urban pluvial floods.