FURTHER READING: "Hong Kong Geology - A 400-million year journey" (September 2009 Edition)

Page 147 to 150 of “Hong Kong Geology – A 400-million year journey”

The Urban Landscape of Hong Kong

Hong Kong has limited flat land for building, and no lakes, large rivers, or major aquifers to provide drinking water. Consequently, flat land has been created by coastal reclamation and site formation, quarrying has provided building materials and concrete aggregates, and water has been stored by building dams and impounding reservoirs. Together, these activities have had a profound effect on the onshore topography, the shape of the coastline, and the drainage pattern of Hong Kong, not only in the urban areas, but also in many of the New Territories villages.

The first proposal for land reclamation in Hong Kong was made in 1855 for the Western Praya Scheme in the area of Kennedy Town. The scheme eventually began in 1868 and was completed in 1873, adding 50 acres (0.2 sq. km) to the waterfront.

A second reclamation scheme commenced in February 1890 and was completed in 1904, using about 3.5 million tonnes of material to create 65 acres (0.3 sq. km) of new land.

Over the succeeding years, the rate of reclamation increased almost exponentially. Between 1868 and 1967 a total of 10.0 sq. km had been reclaimed, between 1967 and 1991 an additional 30.5 sq. km, and between 1991 and 1995 a further 19.0 sq. km were reclaimed. In total, more than 60 sq. km of land have been formed by reclamation.

Most of the New Towns in Hong Kong, including Tin Shui Wai, Ma On Sha, Tseung Kwan O, Sha Tin, Tuen Mun, Tsuen Wan, and Tung Chung, comprise large areas of coastal reclamation.

Also, many of the notable developments in Hong Kong are located on reclaimed land, including the former Kai Tai Airport, the new Chek Lap Kok Airport (12.5 sq. km), large areas of the Kowloon peninsula and Central District on Hong Kong Island, including the West Kowloon Reclamation (3.3 sq. km), as well as the Disneyland complex (2.0 sq. km)

Today, reclaimed land makes up about 6% of the onshore area of Hong Kong, development land that now supports housing for about 20% of the population.

The first reclamations were carried out using material provided by public dumping, including construction and household waste. Bunds were built, and city waste was deposited in lagoons. This method was slow, taking many years to complete.

Several early reclamations were carried out using sand from offshore sources. These included the Kai Tak extensions (1929, 1931 and 1956-1959), the Causeway Bay Typhoon Shelter, Victoria Park, and Tuen Mun New Town.

Many large reclamation were carried out using weathered rock obtained by cutting back into hillsides. This method had the advantages of being faster than public dumping, and also created new land for housing developments in the “Borrow Areas”.

However, there were several disadvantages to using weathered rock. The placed fill required a long period to settle because of the irregular particle sizes, which included large rock fragments, and the material drained slowly because of the clay content. Importantly, severe environmental disturbance was created in city areas during excavation and blasting, and by heavy vehicles transporting material to the coastline.

Offshore sand became the preferred fill option in the 1980s, pioneered by two important projects.

Container Terminal 6 was constructed between 1986 and 1989 using about 8.6M cubic meters of marine dredged sand, and the Tin Shui Wai New Town was constructed between 1986 and 1988 using about 24.0M cubic meters of sand. This method had the advantages of being rapid, creating minimal environmental disturbance onshore, and the placed fill drained and consolidated rapidly.

Major Site Formations

In addition to reclaiming land from the sea, development land is also created by levelling the tops of hills, by completely removing hills, and by cutting platforms back into steep hillsides.

There are many examples of this kind of site formation, at all scales from the erection of small village houses to the construction of vast housing complexes.

As urban development on the Kowloon peninsula gradually spread northwards, several large housing sites, such as Tsz Wan Shan and Chuk Yuen, were developed by cutting back into the Kowloon Foothills. Similarly, major projects such as the Kornhill development involved cutting into the hills on Hong Kong Island.

More recently, the Jordan Valley site formation included the removal of large quantities of rock.

Several projects, such as the Tseung Kwan O New Town development, involve both major site formation and reclamation. Large-scale rock removal created housing platforms on the hillsides surrounding the bay, and much of the excavated rock was used as fill for extensive areas of coastal reclamation.


Authors: Roderick J Sewell, Denise L K Tang & Raynor Shaw
of Civil Engineering and Development Department of HKSARG

Resources:

  1. Geological Map of Hong Kong Web-based Edition (https://www.cedd.gov.hk/eng/about/organisation/geo_map_2.html)
Posted by lunababy22 lunababy22, 02 March, 2019 03:07

Comments

No comments yet.

Add a Comment

Sign In or Sign Up to add comments