Coastal City Profiles

Guangzhou, Shenzhen and Hong Kong, China.

The city of Guangzhou ranks as number 1 on both of the lists of vulnerable coastal cities of the world (World Bank), while Shenzhen ranks number 9 on List A and number 10 on List B. What makes these two cities, which are relatively close to each other geographically rank so high on these two lists?

This discussion will include the region in southern China known as the Pearl River Delta or PRD, which is within Guangdong Province, of which Guangzhou is Capital. Guangzhou (formerly known as Canton) is one of several cities which have merged together to form a mega-city. More detailed information on the economy of this rapidly growing region may be found at:

http://www.sinoptic.ch/guangzhou/pdf/2013/20130322_Fact.sheet_Guangdong.Province.pdf

The third largest city in China, Guangzhou, is the capital of Guangdong Province and has a population of approximately 15 million people. Guangzhou is actually part of a megalopolis formed by the coalescence of several cities. To the south of Guangzhou is Shenzhen, which itself ranks 9 on list A and 10 on List B. South of Shenzhen is Hong Kong. The region of mainland China to the north of Hong Kong is considered one of the more progressive parts of China. In recent years it has seen rapid economic and population growth.

The population of the city of Guangzhou is estimated to be more than 15 million, presenting many issues for city leaders. The rapid growth has occurred mainly because of the influx to the city by people from rural areas. 15 million has been deemed Guangzhou's maximum capacity so city leaders are considering ways to control population growth, while at the same time planning for the relaxation of the one child per family rule imposed by the Chinese government.

This densely populated city sprawls across the Pearl River Delta, a low lying coastal plain formed by the Pearl River and its distributaries as they enter the South China Sea. The low elevation of much of the most densely populated areas is significant to the overall vulnerability of the people living here to inundation in the event of a tropical cyclone and as a result of sea level rise.

Shenzhen to the south is part of the "Special Economic Zones" formed as part of the reform and opening up policy in China. Shenzhen sits in close proximity to Hong Kong and here people move freely between mainland china and Hong Kong.

Hong Kong is today considered a "Special Administrative Region" of the People's Republic of China. China resumed sovereignty from Britain over Hong Kong in 1997. Because of its turbulent political history, Hong Kong is a cosmopolitan region with a large population of non-Chinese residents, setting it apart from its mainland neighbors. It is a mountainous coastal region with an area of a little over 1,000 km and a population of 7 million, most of which live on the low-lying coastal fringe. This makes Hong Kong one of the most densely populated areas in the world. This densely populated fringe of land is highly vulnerable to inundation.

Mumbai, India

Mumbai is a city of more than 13 million people and an example of one of Asia's mega-cities. Rapid urbanization across the globe, but in particular in developing countries, presents many challenges, particularly in low-lying, coastal cities such as Mumbai, which are particularly vulnerable to climate change related hazards. The average elevation of the city is less than 15 meters. What we see as the land occupied by Mumbai today was once actually seven distinct islands separated by water and wetlands. These wet areas were mostly reclaimed by 1900 to create the current footprint of the city. This footprint still technically occupies an island, being surrounded on all sides by water. Large areas of low-lying land border the tidal "creeks" that drain to the Arabian Sea to the west of the city. These were at one time mangrove swamps and have since been reclaimed. Much of the reclaimed land is of very low elevation and subject to frequent flooding. Many of the poor (who comprise more than half the population) of Mumbai live in these areas. Recent rainfall flooding events, particularly those in 2005 and 2010, illustrate the vulnerability of the city's population to flooding. With a tropical, monsoon climate and poor infrastructure available for approximately half of Mumbai's population, these types of events can lead to great human misery, with disease being one of the major consequences of disaster such as flooding.

Further reading about Mumbai can be found in the 2010 document Mumbai City Report:

http://web.archive.org/web/20170329162907/http://startcc.iwlearn.org/doc/Doc_eng_16.pdf

New Orleans, Louisiana, USA

New Orleans was established more than 300 years ago on the banks of the lower Mississippi River for strategic and commercial reasons. The northern perimeter of this port city is the south shore of Lake Pontchartrain, a 629 square mile bay open to the Gulf of Mexico. The city is surrounded on all sides by water and wetlands. Its growth to the current occupied area was facilitated by draining the low-lying swamps and marshes between the Mississippi River and Lake Pontchartrain. Storm water must be pumped out of the city with every rainstorm. The city's relationship with water is currently defined by its complete enclosure within flood protection levees. The older levees protect the city from Mississippi River floods, while newer levees protect the city from inundation by hurricane storm surges from the Gulf of Mexico. The drainage and dewatering of the delta sediment on which New Orleans sits has caused compaction and subsidence so that the elevation of many areas of New Orleans is now below sea level.

The hurricane protection levee system (see image below) failed in 2005 when Hurricane Katrina's storm surge breached it in many places. This resulted in the flooding of 80% of the city, filling the shallow bowl of low lying land with salty water.

The population of New Orleans before Hurricane Katrina was 454,865. The 2012 census estimates the population to 369,250, or 76% of the 2000 population (nola.com). Therefore, New Orleans is a smaller city than before Katrina in terms of numbers of residents. The demographic and other changes in New Orleans since Hurricane Katrina are complex. Although parts of the city still remain relatively unrecovered since the storm, other areas have made great improvements economically and in other ways (see article from the Times Picayune linked below).

Of the four coastal cities featured here, New Orleans is the only U.S. city and it is the only one of the cities to weather a recent major disaster related to coastal hazards. It has received billions of dollars in recovery funds and undergone a major rebuilding of its flood defenses since 2005. These important factors should be taken into account as you analyze the coastal cities on the list and their vulnerability to coastal hazards.