Multi-scenario urban flood risk assessment by integrating future land use change models and hydrodynamic models

Abstract

Abstract. Urbanization and climate change are critical challenges in the 21st century. Flooding by extreme weather events and human activities can lead to catastrophic impacts in fast-urbanizing areas. However, high uncertainty in climate change and future urban growth limit the ability of cities to adapt to flood risk. This study presents a multi-scenario risk assessment method that couples a future land use simulation (FLUS) model and floodplain inundation model (LISFLOOD-FP) to simulate and evaluate the impacts of future urban growth scenarios with flooding under climate change (two representative concentration pathways (RCP2.6 and RCP8.5)). By taking the coastal city of Shanghai as an example, we then quantify the role of urban planning policies in future urban development to compare urban development under multiple policy scenarios (business as usual, growth as planned, growth as eco-constraints). Geospatial databases related to anthropogenic flood protection facilities, land subsidence and storm surge are developed and used as inputs to the LISFLOOD-FP model to estimate flood risk under various urbanization and climate change scenarios. The results show that urban growth under the three scenario models manifests significant differences in expansion trajectories, influenced by key factors such as infrastructure development and policy constraints. Comparing the urban inundation results for the RCP2.6 and RCP8.5 scenarios, the urban inundation area under the growth-as-eco-constraints scenario is less than that under the business-as-usual scenario but more than that under the growth-as-planned scenario. We also find that urbanization tends to expand more towards flood-prone areas under the restriction of ecological environment protection. The increasing flood risk information determined by model simulations helps us to understand the spatial distribution of future flood-prone urban areas and promote the re-formulation of urban planning in high-risk locations.

Application of NEXRAD precipitation data for assessing the implications of low development practices in an ungauged basin

“…In previous studies, the criteria of flood depth to map the risk area are usually compared with urban design settings criteria (Ouma & Tateishi, 2014; Q. Sun et al, 2022), but this study considers the in‐built criteria of PCSWMM. It creates risk map on the basis of two parameters, duration, and depth of flooding (Luu et al, 2018).…”

Sustainable urban planning to control flood exposure in the coastal zones of China

“…Limited by the data availability, the SSP2-4.5 and the SSP5-8.5 were chosen. Drawing upon relevant studies (Mustafa et al, 2018a;Liu et al, 2020b;Sun et al, 2022), we designed five urban planning strategies as follows:…”

“…Even so, our results suggest that UEF in coastal China will continue to mount rapidly. Third, we simply set up the EP planning based on NDVI index without considering other indicators such as permanent basic farmland (Sun et al, 2022), Net Primary Productivity (Liu et al, 2020b), Intact Forest Landscapes (Potapov et al, 2008), and Key Biodiversity Areas (Yang et al, 2020).…”

“…Case studies on future urban land expansion in China's coastal floodplains were also available for localities. Lin et al (2020) and Sun et al (2022) conducted scenario-based coastal flood exposure assessments using the future land use simulation (FLUS) model for the Guangzhou metropolitan area and Shanghai, respectively, and found that without proper urban planning, more built-up areas in both regions would be exposed to flooding. Xu et al (2021a) established different urban growth scenarios based on the CA-Markov model and combined them with the sea level rise scenarios to dynamically evaluate the flood exposure of buildings and infrastructure in Xiamen in 2050, and revealed that sea level rise and urban growth would increase the overall flood exposure to varying degrees.…”

Estimating the carbon footprint of post-flood urban road network restoration efforts: A case study in Carlisle

“…The LISFLOOD-FP model is an open-source 2-D hydrodynamic model developed based on empirical data from UK flood events (Neal et al 2012). It simplified the computations of assessment on an urban (Sun et al 2022), national (Bates et al 2023), or global scale (Sampson et al 2015) by ignoring the advection term of the shallow water function. Taking Carlisle, a flood hotspot in the UK, as the study site and considering data availability, this study introduced the LISFLOOD-FP model to construct the urban flood disaster background.…”