Evolution and prediction of urban flood risk under land use change scenarios: a case study of Tianjin Downtown

The process of urbanization has resulted in alterations to land use patterns and catchment characteristics, which have in turn led to an increase in the frequency of urban flooding.The prediction of future land use in urban areas and the exploration of the evolution of urban flood risk under scenarios of land use change can provide a reference basis for the improvement of urban disaster prevention and mitigation planning and sustainable development.In this study, the Future Land Use Simulation (FLUS) model is employed for the purpose of predicting the land use pattern in 2030.The Maximum Entropy (MaxEnt) model and the risk evaluation indicator system are integrated to identify the principal influencing indicators and their impact on the urban flood risk.Furthermore, the urban flood risk pattern and its evolution under the scenario of land use change are analyzed with Tianjin Downtown as a case study.The results of the study indicate that: (1) The characteristics of land use change in Tianjin are dominated by a decrease in arable land and an increase in construction land.It is predicted that the area of arable land in Tianjin will decrease by about 2.51%, the area of urban construction land will increase by about 3.61%, and the impermeable rate of the urban subsurface will continue to increase from 2020 to 2030.(2) Indicators such as population density, land use type, and precipitation have a high contribution to the distribution of flood risk in Tianjin, while indicators such as imperviousness and green space coverage have a higher importance.(3) The proportion of high-risk area in Tianjin in 2010, 2020 and 2030 is 8.77%, 9.69% and 10.81% respectively.It can be predicted that the area of high-risk area will gradually increase with the expansion of urban construction land in the future.The high-risk areas are mainly concentrated in the central urban areas along the Haihe River.By 2030, the proportion of high-risk areas in Heping District, Hedong District, and Hebei District will exceed 50%.The results of this study provide a foundation for theoretical considerations regarding urban disaster early warning and land use resilience optimization.