Housing plan, at sea

An artificial reef could be the ideal habitat for threatened sea creatures

Published: Tuesday 29 February 2000

will artificial reefs provide a new ecosystem to the dwindling species of marine lifeforms in the near future? The Loch Linnhe Artificial Reef complex, due to be built in Scotland, may answer this and other important questions about reef ecology.

In a unique partnership with the industry, researchers at the Centre for Coastal and Marine Sciences ( ccms ) laboratory at Dunstaffnage, near Oban in Scotland, hope to build one of the largest experimental reefs in the world. Construction of the 50,000-tonne Loch Linnhe Reef is scheduled to start in July 2000.

This is not the first attempt to create artificial reefs. In the 1960s and 1970s, for instance, 'second use' materials such as old cars, trains and tyres were used to make reefs. However, in a few years, they were reduced to a pile of rusty junk.

Another method of constructing reefs is by using concrete. However, because of its prohibitive cost, it does not become economically-viable. Thus, the researchers at ccms had to think of a viable alternative. They found one in the fine granite power, which is a byproduct of the quarrying industry. It is here that a quarrying company Foster Yeoman Limited, which is also one of sponsors of the project, entered the scene.

After an extensive research and help from consultants, who had worked with the Channel Tunnel project, a cost-effective concrete block was developed using four per cent cement and another four per cent of fly ash, a byproduct of thermal power plants. The block is five times stronger than the British standard for construction blocks and is chemically-inert even under extreme conditions of temperature and abrasion ( NERC News , Autumn 1999).

Finding a perfect site for the reef was another problem. Easy access to the site, depth of the water and proximity to tidal streams are all important factors to be kept in mind while choosing the site. After an extensive search, the researchers identified a site which lies on the east of Lismore, just 8 kilometres from Dunstaffnage. The site was approved by local community councils and fisherfolk representatives, an essential for gaining the necessary licences for this kind of construction.

With a guaranteed supply of high-quality blocks and a perfect site for an artificial reef, the next stage will involve the building of the reef itself. The complex will cover an area of about nine football fields and consist of 24 individual reefs. Each reef will be made of over 50,000 concrete blocks and will occupy an area of about 650 square metres and a height of 2-3 metres. The actual size of each module will depend on the use of solid blocks or blocks with voids.

Reefs are an ideal place for marine plants and animals to grow. But whether the huge artificial reef in Scotland will create a paradise for marine species, a disposal site for quarry byproducts and allow research into marine ecology will be seen in the near future. For now, at least interest among local fisherfolk for the lobster-ranching potential of the reef is already growing.

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