| 摘要: |
| 气候变化背景下，高密度沿海城市受
到风暴潮和极端降雨引起的洪涝灾害冲击。文
章基于韧性理论构建城市空间洪涝风险指标
体系，制定该评价框架的实施路径；基于水文
软件Mike21、GIS平台及其空间网络分析插件
sDNA，复合“天鸽”台风风暴潮与极端降雨情
景，整合深圳湾地区的路网和土地利用进行危
险性、暴露度、脆弱性和适应能力等多源数据；
通过GIS栅格计算得到各要素层分析及洪涝风
险评价可视化地图，结果显示，潮、洪、涝突破
刚性标准加剧了危险性，高密度城市环境增大了
危险区域的暴露度，路网和土地利用布局具有
一定脆弱性，需完善应急疏散和避难场所规划以增强适应能力；根据评价地图识别高风险片区，从路网和土地利用等城市空间物质要素出发，
提出应对洪涝灾害的适应性规划策略。 |
| 关键词: 风暴潮 城市空间 洪涝风险评价 城市韧性 适应能力 深圳湾地区 |
| DOI：10.13791/j.cnki.hsfwest.20230419 |
| 分类号: |
| 基金项目:华南理工大学亚热带建筑与城市科学全国重点实验
室自主研究课题项目（2021202）；华南理工大学亚热
带建筑与城市科学全国重点实验室自主研究课题项目
（2022KA01） |
|
| Flood Risk Assessment and Adaptive Planning Strategies in High-Density Coastal Areas: A Case Study of Shenzhen Bay Area |
|
CHEN Bilin,SUN Yimin,LI Ying long
|
| Abstract: |
| In the context of climate change, high-density coastal cities are threatened by floods
caused by storm surge and extreme rainfall. In order to enhance flood resilience of these cities, it
is necessary to formulate adaptive urban planning responses to flood events. When making these
responses, as complex dynamic systems, high-density coastal cities should not only consider the
impact of multiple triggering agents including tide level, wind field and precipitation rate, but also
need to understand the characteristics and damaged conditions of urban physical spatial elements
which are exposed to flood risks. Therefore, this paper attempts to establish theoretical connection
between urban resilience and flood risk management, fill the gap of research on adaptive capacity of
urban spatial elements which cope with flood risks caused by multiple triggering agents, build up an
integrated flood risk predictive mechanism with multi-source data, identify the scope and intensity
of urban flood risks, and provide more accurate spatial informative feedbacks for decision makers, so
as to put forward flood-adaptive urban planning strategies accordingly.
Based on resilience theory, this paper constructs an urban spatial flood risk index system,
adopts the flood risk analytical framework of hazard-exposure-vulnerability-adaptive capacity, sorts
out the sub-indicators of this framework, and formulates flood risk assessment pathways according
to scenario-based simulation and spatial metrology. Coupled inundation scenarios of Typhoon Hato
and extreme rainfall in Shenzhen Bay Area are illustrated, the spatial distribution and characteristics
of road network and land use pattern of this area are identified, and the multi-source data of hazard,
exposure, vulnerability and adaptive capacity are integrated, with the support of Mike21, a two dimensional hydrodynamic module of DHI software, crawler technology by python, GIS platform
and sDNA, a spatial network analytical plug-in. With non-dimension of the above data, a visualized
map is obtained by GIS grid computing to present the overall flood risk level in Shenzhen Bay Area.
Results demonstrate that: 1) Tide, flood and waterlogging exacerbate flood hazard by exceeding
rigid standards. Dense coastal areas of Shenzhen Bay are threatened by the high water level caused
by storm surge, which verifies that it is difficult to deal with flood uncertainties only relying on
high-standard engineering means, while low-lying inner urban areas are affected by the long-term
extreme rainstorms continuously with the failure of drainage system, which suggests that a more
resilient measure of rainwater storage should be taken to alleviate waterlogging problems; 2) High density urban environment intensifies flood exposure of the risking areas. Road network and urban
functional configuration of Shenzhen Bay Area reflect a decentralized concentration pattern, with
the high-density and high-cluster areas facing higher levels of flood hazard; 3) Layouts of road
network and land use are endowed with certain flood vulnerability in Shenzhen Bay Area. Problems
such as discontinuous urban blue-green infrastructure system, high centrality and traffic dependence
on the east-west arterial roads, and high vulnerability degree of land use pattern around high-hazard areas have emerged; 4) Urban flood evacuation and emergency shelters should be improved to enhance adaptive capacity with resilient planning and design
interventions such as establishing an efficient street network and strengthening compact land use, so as to reduce flood risk level of coastal cities.
According to the visualized map, areas of high flood risk are identified, and resilient planning strategies adaptive to flood disasters are put forward
accordingly, with the regulation of urban physical spatial elements such as street network and land use: 1) In high-hazard areas, a storm surge barrier
combined with rigid and flexible infrastructural defense should be established for tide and flood problems, while a decentralized three-dimensional rainwater
storage system is well-advised to be constructed to mitigate urban waterlogging; 2) In high-exposure areas, for low-lying road systems, their ground
elevation should be raised above the flood level or it would be better to construct three-dimensional pedestrian paths through vertical design as back-up
traffic links; for intensified-developed urban blocks, modular design is suggested to optimize land use layout, which turns the modules impacted by flood
events into flexible, multifunctional places; 3) In high-vulnerability areas, it is proposed to upgrade ecosystem services for flood resilience by relinking blue green system, strengthen redundancy by densifying street network and lowering centrality of the main roads, as well as fortify coastal land use regulation by
controlling the disorderly development in high-hazard land; 4) In low-adaptive areas, it is necessary to formulate evacuation routes, increase the accessibility
of street network and emergency shelters, and promote compact land use to maintain urban livelihood, so as to improve flood resilience in high-density urban
environment.
To sum up, the assessment framework of hazard-exposure-vulnerability-adaptive capacity with the integrated analysis of multi-source data, enriches the
research method of making flood inundation map in the past, and further de-structures the dynamics of flood risk combined with spatial configuration and
attributes of urban morphological elements in multiple dimensions and aspects. Therefore, it facilitates researchers to understand the complexity of flood risk
with Shenzhen Bay Area as a showcase and adopt corresponding urban spatial flood-adaptive responses, which may provide guidance for the future research
on flood-resilient urban design in high-density coastal cities. |
| Key words: Storm Surge Urban Space Flood Risk Assessment Urban Resilience Adaptive Capacity Shenzhen Bay Area |
