Thesen Islands: Innovative Environmental Advancements Marina Development
Thesen Islands development is an ambitious and technically complicated project where the 96-hectare Thesen Island in Knysna, South Africa, is master planned into an estate of 19 islands surrounded by wide tidal waterways linked by bridges. Fifteen kilometres of pristine water front property needs to be protected in the most environmentally friendly way possible against the erosive forces of fluctuating tide levels and associated wave action to ensure that the islands will be developed in harmony with the Knysna Estuary environment. After thorough site trials and investigations, hexagonal woven mesh products: Reno mattresses; gabions and Terramesh? were found to be the only alternative in achieving the onerous standards and criteria as set out in the project specifications, i. e. environmental compliance, durability under aggressive marine environments, ease of installation and vegetation establishment, and cost effectiveness. The chosen solution is able to protect each idyllic island against scour arising from inter tidal action and can also ensure the stability of the bank especially under rapid draw down conditions. As a result, the tidal flow around the islands is completely natural with excellent circulation, water quality and minimal silting. A state of the art modelling system developed by The Danish Hydraulic Institute was used to assist with the design and layout of the waterways. Hydraulic and hydrological modelling, which even accounts for climate change, should ensure that the Islands are completely safe from flooding. A bioengineering approach is being taken to the construction. Indigenous salt marsh plants are being used in conjunction with the inert materials in the inter-tidal zone. Small fish and marine life find food and shelter in the plants and natural rock along the edges of the waterways, which in turn, attract a diversity of birds and larger fish resulting in habitat improvement. The rock filled gabions provide surfaces for growth of algal-microbial films, which may contribute to nitrogen and phosphorus uptake from the tidal flow, thus reducing phytoplankton growth potential in the canals. The Deputy Minister of Environmental Affairs and Tourism, Minister Ms. R. T. Mabudahfhasi has commended the developers for the most responsible manner in which they conducted, supported and financed the environmental research, which probably represents the most comprehensive, professional and detailed Environmental Impact Assessment ever undertaken in South Africa.
dewatering salt marsh transplantation environmental compliance marina development gabion technology, bioengineering
Laura Giuliano James Wang
Officine Maccaferri S. p. A. Bologna, 40123, Italy Maccaferri China Hunan, 410001, China
国际会议
山东东营
英文
278-288
2007-10-16（万方平台首次上网日期，不代表论文的发表时间）