Rapid Urbanization and Implications for Flood Risk Management in Hinterland of the Pearl River Delta, China: The Foshan Study

In recent decades, the Pearl River Delta (PRD) region has experienced strong economic and population growth. By 2050 120 million people are expected to live in the region, which currently has eleven major cities, and the emerging mega-city formed by Hong Kong, Shenzhen and Guangzhou. The populous coastal cities and low lying flood plains in the PRD experience flood risk via: (i) intense precipitation from storms, (ii) inland pluvial flooding, (iii) storm surges. Climate change, including global sea level rise forecasts of more than 1 m by 2100, mean that flood risk is expected to increase in future. Sustainable flood risk management (SFRM) must be adopted to mitigate these risks. Strategies such as the UK's ‘making space for water’ programme seek to tackle flood risk through planning, but such a strategic approach is not evident in the PRD. Recent coastal land reclamation projects in the PRD illustrate the conflict between urban growth pressure and flood risk, and that more comprehensive, or sustainable, flood risk management is not currently practiced. This paper examines flood risk management practice in the PRD. It starts with a theoretical sustainable flood risk appraisal (SFRA) template developed from literature and global best practice, against which PRD practice is benchmarked. The paper discusses a case study in Hong Kong and Shenzhen where in-depth discussions with more than 30 stakeholders were held to understand barriers and constraints to realising SFRM. This research seeks to further the practice of SFRM in the PRD, and comparable urbanising mega-deltas in the region.

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Spatio-temporal dynamics of flood exposure in Shenzhen from present to future

Environment and Planning B Urban Analytics and City Science ◽

10.1177/2399808321991540 ◽

2021 ◽

pp. 239980832199154

Author(s):

Gizem Mestav Sarica ◽

Tinger Zhu ◽

Wei Jian ◽

Edmond Yat-Man Lo ◽

Tso-Chien Pan

Keyword(s):

Pearl River Delta ◽

Temporal Dynamics ◽

Flood Hazard ◽

River Delta ◽

Pearl River ◽

Rapid Urbanization ◽

The Pearl River Delta ◽

Flood Exposure ◽

Spatio Temporal ◽

The Pearl River

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.

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Examining the Density and Diversity of Human Activity in the Built Environment: The Case of the Pearl River Delta, China

Sustainability ◽

10.3390/su12093700 ◽

2020 ◽

Vol 12 (9) ◽

pp. 3700

Author(s):

Miaoxi Zhao ◽

Gaofeng Xu ◽

Martin de Jong ◽

Xinjian Li ◽

Pingcheng Zhang

Keyword(s):

Built Environment ◽

Human Activity ◽

Pearl River Delta ◽

Positive Impact ◽

River Delta ◽

Pearl River ◽

Rapid Urbanization ◽

Land Use Efficiency ◽

The Pearl River Delta ◽

The Pearl River

Rapid urbanization in China has been accompanied by spatial inefficiency in patterns of human activity, of which ‘ghost towns’ are the most visible result. In this study, we measure the density and diversity of human activity in the built environment and relate this to various explanatory factors. Using the Pearl River Delta (PRD) as an empirical case, our research demonstrates the distribution of human activity by multi-source data and then explores its dynamics within these areas. This empirical study is comprised of two parts. The first part explores location information regarding human activity in urbanized areas and shows density and diversity. Regression models are applied to explore how density and diversity are affected by urban scale, morphology and by a city’s administrative level. Results indicate that: 1) cities with smaller populations are more likely to be faced with lower density and diversity, but they derive greater marginal benefits from improving land use efficiency; 2) the compactness of the layout of urban land, an index reflecting the plane shapes of the built environment, is highly correlated with density and diversity in built-up areas; and 3) the administrative importance of a city has a significant and positive impact on the density of human activity, but no obvious influence on its diversity.

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Response of the Sea Breeze to Urbanization in the Pearl River Delta Region

Journal of Applied Meteorology and Climatology ◽

10.1175/jamc-d-18-0081.1 ◽

2019 ◽

Vol 58 (7) ◽

pp. 1449-1463 ◽

Cited By ~ 2

Author(s):

Cheng You ◽

Jimmy Chi-Hung Fung ◽

Wai Po Tse

Keyword(s):

Pearl River Delta ◽

Coastal Region ◽

Sea Breeze ◽

River Delta ◽

Pearl River ◽

Pearl River Delta Region ◽

Start Time ◽

Rapid Urbanization ◽

The Pearl River Delta ◽

The Pearl River

AbstractThe Pearl River delta (PRD) region has undergone rapid urbanization since the 1980s, which has had significant effects on the sea-breeze circulation in this region. Because the sea breeze plays an important role in pollutant transportation and convective initiation in the PRD region, it is meaningful to study the effects of urbanization on the sea breeze. In this study, three numerical experiments were conducted from 2 June to 31 August 2010 with land-use data from 1988, 1999, and 2010. For each simulation, characteristics of the sea breeze such as the start time, end time, intensity, height, pumping ability, and inland penetration distance were quantified. By comparing the characteristics of the sea breeze in these simulations, its response to urbanization was quantified. The results show that urbanization enhances the duration, height, and intensity of the sea breeze but blocks its inland penetration. One physical mechanism is proposed to dynamically elucidate the response of the sea breeze to urbanization. Because the urban area in the PRD region is concentrated near the coast, urbanization imposes a positive heating gradient on the coastal region and a negative heating gradient on the region farther inland. The positive heating gradient may intensify the sea breeze, and the negative heating gradient may prevent the sea breeze from propagating farther inland.

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