The Pearl River Delta metropolitan region is one of the most densely urbanized megapolises worldwide with high exposure to weather-related disasters such as storms, storm surges and river floods. Shenzhen megacity has been the fastest growing city in the Pearl River Delta region with a significant increase of resident population from 0.32 million in 1980 to 13.03 million in 2018. Being a flood-prone city, Shenzhen’s rapid urbanization has further exacerbated potential flood losses and forthcoming risk. Thus, evaluating the changes in its exposure from present to future is essential for flood risk assessment, mitigation and management purposes. The main objective of this study is to present a methodology to assess the spatio-temporal dynamics of flood exposure from present to future using high-resolution and open-source data with a particular focus on the built-up area. To achieve this, the SLEUTH model, a cellular automata-based urban growth model, was employed for predicting the built-up area in Shenzhen in 2030. An almost threefold increase was observed in total built-up area from 421 km² in 1995 to 1166 km² in 2030, with the 2016 built-up area being 858 km². Built-up areas, both present (2016) and projected (2030), were then used as the land cover input for flood hazard assessment based on a fuzzy comprehensive evaluation model, which classified the flood hazard into five levels. The analysis indicates that the built-up area subjected to the two highest flood hazard levels will increase by almost 88% (212 km²) from present to future. The approach presented here can be leveraged by policymakers to identify critical areas that should be prioritized for flood mitigation and protection actions to minimize potential losses.

珠江三角洲都会区是世界上最密集的城市化大都市之一，极易遭受与天气有关的灾害，例如风暴，风暴潮和河流洪水。深圳特大城市一直是珠江三角洲地区增长最快的城市，常住人口从1980年的32万大幅增加到2018年的1303万。作为易受洪涝灾害的城市，深圳的快速城市化进一步加剧了潜在的洪灾损失和即将来临的洪灾。风险。因此，评估洪水从现在到未来的变化对于洪水风险评估，缓解和管理目的至关重要。这项研究的主要目的是提出一种方法，该方法使用高分辨率和开放源代码数据，尤其是对建成区的评估，来评估从现在到未来洪水泛滥的时空动态。为此，SLEUTH模型是一种基于元胞自动机的城市增长模型，用于预测2030年深圳的建成区。从421 km的总建成区中观察到几乎增加了三倍² 1995年1166公里²在2030年，与2016年建成区面积为858公里²。然后，基于模糊综合评价模型，将当前（2016年）和预计（2030年）的建成区用作洪水灾害评估的土地覆盖输入，将洪水灾害分为五个级别。分析表明，从现在到将来，遭受两次最高洪灾危害的建筑面积将增加近88％（212 km ²）。政策制定者可以利用此处介绍的方法来确定应优先考虑的关键领域，以减轻洪水和采取保护行动，以最大程度地减少潜在损失。