Land reclamation


Land reclamation, often known as reclamation, and also known as land fill, is the process of creating new land from oceans, seas, riverbeds or lake beds. The land reclaimed is known as reclamation ground, reclaimed land, or land fill. The term "reclamation" is a misnomer, and promotes confusion with land rehabilitation.

History

In ancient Egypt, the rulers of the Twelfth Dynasty undertook a far-sighted land reclamation scheme to increase agricultural output. They constructed levees and canals to connect the Faiyum with the Bahr Yussef waterway, diverting water that would have flowed into Lake Moeris and causing gradual evaporation around the lake's edges, creating new farmland from the reclaimed land. A similar land reclamation system using dams and drainage canals was used in the Greek Copaic Basin during the Middle Helladic Period. Another early large-scale project was the Beemster Polder in the Netherlands, adding of land in 1612. In Hong Kong, the Praya Reclamation Scheme added of land in 1890 during the second phase of construction. It was one of the most ambitious projects undertaken during the era of colonial Hong Kong. Some 20% of land in the Tokyo Bay area has been reclaimed, most notably Odaiba artificial island. The city of Rio de Janeiro was largely built on reclaimed land, as was Wellington, New Zealand. During the 18th and 19th centuries The Seven Islands of Bombay were joined with the help of several land reclamation projects like Hornby Vellard and Colaba Causeway

Methods

Land reclamation can be achieved by a number of different methods. The simplest method involves filling the area with large amounts of heavy rock and/or cement, then filling with clay and dirt until the desired height is reached. The process is called "infilling" and the material used to fill the space is generally called "infill". Draining of submerged wetlands is often used to reclaim land for agricultural use. Deep cement mixing is used typically in situations in which the material displaced by either dredging or draining may be contaminated and hence needs to be contained. Land dredging is also another method of land reclamation. It is the removal of sediments and debris from the bottom of a body of water. It is commonly used for maintaining reclaimed land masses as sedimentation, a natural process, fills channels and harbors.

Notable instances

Africa