'Skyscrapers from the sea' - Ceri James from the British Geological Institute. (2001-01-31)
Land reclamation in South East Asia was the subject of this talk. Mr James worked in Hong Kong for two years, supervising the construction of the new airport there. The subject matter was technical, but Ceri gave everyone a clear idea of what was going on - making the prospect of building a 'floating airport' deceptively simple!
Ceri concentrated on the social and economic reasons for land reclamation. He use slides and old maps to show how the first reclamations were for armaments and cemeteries, as far back as the 1860's. I never realised the technology existed to carry out such complicated construction then! Today with the price of land astronomically high, every inch of land that can be salvaged from the sea is vital, and the shape of Kowloon, the main peninsula, has almost merged with the mainland. The airport itself covers an area larger than Central Leeds, from Harefields to Headingley. Hong Kong's once broad harbour has now shrunk. Aerial photographs make the place look more like the Thames Estuary.
Other huge reclamation projects are going on in other parts of Asia. Apparently Korea's left coast has huge amounts of sand banks, perfect for land reclamation. Two islands are currently being joined together there to make an offshore airport. Land is reclaimed by first constructing barriers around the area to be reclaimed, and then starting from one end mud and sand dredged up from the sea bed is poured into the area. Once the land is filled in you inject sand into the soil to encourage water to drain out ( Ok, I admit I didn't quite get this bit).
Ceri showed us photographs of the amazing airport in the sea at Kansei, Japan. It looked like something out of Waterworld - an airstrip in the sea. 200million cubic meters of earth were used to build up the land under the airport. He explained that because land settles with the weight of buildings, the whole construction has to be built several metres above the level required, so that it sinks down to the right level. If you get this wrong everyone will get wet feet...
Ceri's talk was a little like a school geography lesson, but he touched on history, international relations, environmental and cultural aspects of his subject. A very interesting talk, where you could honestly say you had really learned something new!
summary by Kate Mulrenan