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reclamation of land

 
Sci-Tech Dictionary: land reclamation
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(′land ′rek·lə′mā·shən)

(civil engineering) land accretion
(mining engineering) The process by which seriously disturbed land surfaces are stabilized against the hazards of water and wind erosion.

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Sci-Tech Encyclopedia: Land reclamation
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The process by which seriously disturbed land surfaces are stabilized against the hazards of wind and water erosion. Surface mining for coal is responsible for almost one-half of the total land area disturbed in the United States. The drastic disturbance of the overburden severely changes the chemical and physical properties of the resulting spoils. These altered properties often create a hostile environment for seed germination and subsequent plant growth. Unless vegetative cover is established almost immediately, the denuded areas are subject to both wind and water erosion that pollute surrounding streams with sediment.

In the United States the Federal Strip Mine Law requires that topsoil be removed and reapplied on the spoil surface during regrading and reclamation. This practice alone has aided materially in reclamation of surface mine spoil areas throughout the United States. Even when topsoil is reapplied, the surface may contain coarse-textured materials and rock fragments, making it difficult to establish vegetative cover. Many of the eastern mine spoils are derived from sandstone and shales and have a low water-holding capacity. These spoils tend to form crusts and thus create a water-impermeable layer. Practically all of these topsoils have low fertility and thus require extensive fertilization for reclamation and seedling establishment. See also Surface mining.

 
Columbia Encyclopedia: reclamation of land
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reclamation of land, practice of converting land deemed unproductive into arable land by such methods as irrigation, drainage, flood control, altering the texture and mineral and organic content of soil (see fertilizer), and checking erosion. In the United States, all these methods have been used, but the chief effort has been through irrigation. Under the Reclamation Act of 1902, the Bureau of Reclamation supplies water, subsidized by taxpayers, to farmers on arid lands in 17 western states (see Reclamation, United States Bureau of). The irrigation water has increased production, but at some cost: selenium and salinity poisoning have damaged land once reclaimed, competition has grown between agriculture and municipal interests, and wildlife habitat has been jeopardized. Additional aims of the reclamation program include hydroelectric power generation, recreation, and flood control.

History of Reclamation in the United States

While irrigation schemes were built in the Southwest before the coming of the Spanish, by the Catholic missions in California, and by Mormons in Utah by 1847, moves to gain government help for reclamation schemes began with the Carey Land Act (1894). Focusing on the conservation of natural resources during the presidency of Theodore Roosevelt, reclamation was advocated for lands ruined by injudicious farming, grazing, and deforestation as well as for lands with little rainfall.

The Reclamation Act of 1902 provided that the federal government should plan and construct irrigation projects using the proceeds of public land sales, and that the water users (usually organized in some type of cooperative) should liquidate the cost and purchase the irrigation works over a period of 10 years. The program was vigorously pushed by Secretary of the Interior Ethan Allen Hitchcock. Among the many projects started then were the Truckee-Carson project (see Newlands project) and the Salt River project (see Salt River valley). The 1902 act had an acreage-limitation provision, but it did not halt the process of speculation in lands to be irrigated, which made costs to the actual farmers prohibitive. In 1914 the period of time for the water users to pay for the project was lengthened to 20 years (later raised to 40 years).

Interest in reclamation quickened after terrible droughts in the late 1920s and early 30s, and in the public works program of the New Deal under Franklin D. Roosevelt the reclamation program was linked with projects for flood control and for the development of power. The Bureau of Reclamation began to work alongside the U.S. Army Engineers Corps in building dams and forwarding multipurpose projects. The Flood Control Act of 1944 broadened the powers of the federal government in these matters.

Reclamation has created much new wealth in the United States by turning areas that had formerly been arid into thriving agricultural and industrial communities. However, environmentalists have questioned and even stopped more recent projects, such as the Bureau's 1991 water project on the Colorado River, due to the damage to the environment such dam building has caused. The Columbia River complex has had to limit the amount of water diverted to safeguard spawning salmon, and the Omnibus Water Bill of 1992 limited the bureau to environmentally sound projects. Further, criticism that the bureau's programs have disproportionately aided large, rich farms led, in the 1992 bill, to the restriction of water subsidies to family farms.

Bibliography

See F. Powledge, Water (1982); M. P. Reisner, Cadillac Desert (1986).

Wikipedia: Land reclamation
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  It has been suggested that this article be split into articles entitled Land reclamation and Land restoration, accessible from a disambiguation page. (Discuss)

Land reclamation is either of two distinct practices. One involves creating new land from sea or riverbeds, the other refers to restoring an area to a more natural state (such as after pollution, deforestation or salination) have made it unusable, though its the former definition for which the phrase is most widely used.

Contents

Creating new land

The entire East Coast Park in Singapore was built on reclaimed land with a man-made beach.

For habitation or agriculture

Land reclamation can be the creation of new land where there was once water. Notable examples in the West include parts of New Orleans; Washington, D.C. (which is partially built on land that was once swamp); Mexico City (which is situated at the former site of Lake Texcoco); Helsinki (of which the major part of the city center is built on reclaimed land); the Cape Town foreshore; the Chicago shoreline; the Manila Bay shoreline; Back Bay, Boston, Massachusetts; Battery Park City, Manhattan; the port of Zeebrugge in Belgium; the southwestern residential area in Brest, Belarus, the polders of the Netherlands; and the Toronto Islands, Leslie Street Spit, and the waterfront in Toronto. In the Far East, Japan, the southern Chinese cities of Hong Kong, Shenzhen and Macau, the Philippine capital Manila, and the city-state of Singapore, where land is in short supply, are also famous for their efforts on land reclamation. One of the earliest and famous project was the Praya Reclamation Scheme, which added 50 to 60 acres (240,000 m2) of land in 1890 during the second phase of construction. It was one of the most ambitious projects ever taken during the Colonial Hong Kong era.[1] Some 20% of land in the Tokyo Bay area has been reclaimed.[2] Monaco and the British territory of Gibraltar are also expanding due to land reclamation. The city of Rio de Janeiro was largely built on reclaimed land.

Artificial islands are an example of land reclamation. Creating an artificial island is an expensive and risky undertaking. It is often considered in places that are densely populated and flat land is scarce. Kansai International Airport (in Osaka) and Hong Kong International Airport are examples where this process was deemed necessary. The Palm Islands, The World and hotel Burj al-Arab off Dubai in the United Arab Emirates are other examples of artificial islands.

A related practice is the draining of swampy or seasonally submerged wetlands to convert them to farmland. While this does not create new land exactly, it allows commercially productive use of land that would otherwise be restricted to wildlife habitat. It is also an important method of mosquito control.

For beach restoration

Main article: Beach nourishment

Beach rebuilding is the process of repairing beaches using materials such as sand or mud from inland. This can be used to build up beaches suffering from beach starvation or erosion from longshore drift. It stops the movement of the original beach material through longshore drift and retains a natural look to the beach. Although it is not a long-lasting solution, it is cheap compared to other types of coastal defences.

Environmental impact

Parts (highlighted in brown) of the San Francisco Bay were reclaimed from wetlands for urban use.

Draining wetlands for ploughing, for example, is a form of habitat destruction. In some parts of the world, new reclamation projects are restricted or no longer allowed, due to environmental protection laws.

Environmental legislation

Hong Kong legislators passed the Protection of the Harbour Ordinance in 1996 in an effort to safeguard the increasingly as threatened Victoria Harbour against encroaching land development.[3]

Land amounts added

Land reclamation in Hong Kong: Grey (built), Red (proposed or under development). Note that most of the urban area (not shown in map) of Hong Kong is on the reclaimed land.
  • Netherlands - about 1/5 land from land reclamation or about 7,000 km².
  • South Korea - As of 2006, 38 percent or 1,550 km² of coastal wetlands reclaimed.
  • Singapore - 20% of the original size or 135 km² as of 2003, plans for 99 km² more.[4]
  • Hong Kong - (Main article: Land reclamation in Hong Kong)
Praya Reclamation Scheme began in the late 1860s that consisted of two stage totaling 50 to 60+ acres.[1][5] Hong Kong Disneyland, Hong Kong International Airport, and its predecessor, Kai Tak Airport, were all built on reclaimed land. In addition, much reclamation has taken place in prime locations on the waterfront on both sides of Victoria Harbour. This has raised environmental issues of the protection of the harbour which was once the source of prosperity of Hong Kong, traffic congestion in the Central district,[6] as well as the collusion of the Hong Kong Government with the real estate developers in the territory.[7][8]
In addition, as the city expands, new towns in different decades were mostly built on reclaimed land, such as Tuen Mun, Tai Po, Shatin-Ma On Shan, West Kowloon, Kwun Tong and Tseung Kwan O.
  • Macau - 170% of the original size or 17 km² [1]
  • Tokyo Bay, Japan - 249 km².[9]
  • Kobe, Japan - 23 km² (1995).
  • Bahrain - 76.3% of original size of 410 km2(1931-2007).
  • New Zealand - significant areas of land totalling several hundred hectares have been reclaimed along the harbourfront of Auckland, Wellington and Dunedin. In Dunedin - which in its early days was nicknamed "Mudedin" - around 2.5 km², including much of the inner city and suburbs of Dunedin North, South Dunedin and Andersons Bay is reclaimed from the Otago Harbour, and a similar area in the suburbs of St Clair and St Kilda is reclaimed swampland.

Repairing damaged land

Land reclamation or Land rehabilitation is also the process of cleaning up a site that has sustained environmental degradation, such as those by natural cause (desertification, ...) and those caused by human activity (strip mining, ...). Land reclamation is often done in these sites to allow for some form of human use (such as a housing development) or to restore that area back to its natural state as a wildlife habitat home.

Reclaiming desert land

Further information: Desertification#Countering_desertification

Land reclamation in deserts involves

  • setting-up reliable water provisioning (eg by digging wells or placing long-distance water pipes)
  • stabilizing and fixating the soil

Stabilizing and fixating the soil is usually done in several phases.

The first phase is fixating the soil to such extent that dune movement is ceased. This is done by grasses, and plants providing wind protection such as shelterbelts, windbreaks and woodlots. Shelterbelts are wind protections composed of rows of trees, arranged perpendicular to the prevailing wind, while woodlots are more extensive areas of woodland. [10]

The second phase involves improving/enriching the soil by planting nitrogen-fixating plants and using the soil immediately to grow crops. Nitrogen fixating plants used include clover, yellow mustard, beans, ... and food crops include wheat, barley, beans, peas, sweet potatoes, date, olives, limes, figs, apricot, guave, tomato, certain herbs, ... Regardless of the cover crop used, the crops (not including any trees) are each year harvested and/or plowed into the soil (eg with clover, ...); in addition a each year the plots are used for a another type of crop (known as crop rotation) to prevent depleting the soil on specific trace elements.

A recent development is the Seawater Greenhouse and Seawater Forest. This proposal is to construct these devices on coastal deserts in order to create freshwater and grow food [11]

A similar approach is the Desert Rose concept [12]

These approaches are of widespread applicability, since the relative costs of pumping large quantities of seawater inland are low[13].

Another related concept is ADRECS - a proposed system for rapidly delivering soil stabilisation and re forestation techniques coupled with renewable energy generation[14].

See also

References

  1. ^ a b Bard, Solomon. [2002] (2002). Voices from the Past: Hong Kong 1842-1918. HK University press. ISBN 9622095747
  2. ^ Petry, Anne K. (July 2003). "Geography of Japan". Japan Digest, Indiana University. http://iis-db.stanford.edu/docs/129/geo.pdf. Retrieved 2009-07-30. 
  3. ^ Wallis, Keith (February 12, 1996). "Bill seeks to protect harbour". Hong Kong Standard. http://www.thestandard.com.hk/news_detail.asp?pp_cat=&art_id=23201&sid=&con_type=1&d_str=19960212&sear_year=1996. Retrieved 2007-03-23. 
  4. ^ "Singapore Finds it Hard to Expand Without Sand". Planet Ark. http://www.planetark.com/dailynewsstory.cfm?newsid=30328. Retrieved 2007-03-23. 
  5. ^ Jason Wordie, Land-grabbing titans who changed HK's profit for good, April 18, 1999
  6. ^ "Courts protect our imperiled waterway - at least for the time being". Hong Kong Standard. August 14, 2006. 
  7. ^ DeGolyer, Michael (March 15, 2007). "Commentary: Just Looking for Answers". Hong Kong Standard. http://www.thestandard.com.hk/news_detail.asp?pp_cat=15&art_id=40170&sid=12642159&con_type=1&d_str=20070315&sear_year=2007. Retrieved 2007-03-23. 
  8. ^ Ng, Michael (October 5, 2006). "Lawmaker warns of West Kowloon arts venue glut". Hong Kong Standard. http://www.thestandard.com.hk/news_detail.asp?pp_cat=11&art_id=28758&sid=10237275&con_type=1&d_str=20061005&sear_year=2006. Retrieved 2007-03-23. 
  9. ^ "Japan Fact Sheet". Japan Reference. http://www.jref.com/society/japan_fact_sheet.shtml. Retrieved 2007-03-23. 
  10. ^ Desert reclamation
  11. ^ The Sahara Project a new source of freshwater food and energy
  12. ^ Desert Rose - Claverton Group Energy Conference, Bath October2008
  13. ^ http://www.claverton-energy.com/pipe-headloss-power-calculator-calculate-how-much-energy-to-pump-seawater-to-the-middle-of-the-sahara-or-gobi-desert-for-desalination-in-the-seawater-greenhouse-answer-not-a-lot.html claverton energy group article
  14. ^ http://www.claverton-energy.com/download/320/

External links

  • Reclamation of waterlogged and saline soils: [2] , free downloads of software and articles on land drainage.
  • Youcanchangetheplanet.org - A non-profit organization dedicated to sustainable conservation and the rehabilitation of damaged ecosystems.

This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)

 
 

 

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