Winter 2016

TenCate Geotube® technology for land reclamation Amwaj Islands

TenCate Geotube® technology has been applied for the land reclamation and protection of the island complex Amwaj Islands (Bahrain). Application of TenCate Geotube® technology contributed to the efficiency of the construction and turned out to be 50% cheaper than the original quotation specifying the traditional rock-based method. An additional advantage is the minor impact on the environment. 

Bahrain (‘Two seas’) is an archipelago of some 33 islands in the Arabian Gulf. The Amwaj Islands (Arabic: Juzur Amwaj) are a group of artificial islands located to the northeast of the island Muharraq between the Arabian Gulf and Bahrain Sea. The total surface area amounts to 4.31 km². The project was announced in 2000 with construction beginning in April 2001. It is delivered in three phases: dredging and reclamation (completion 2003), infrastructure (completion 2006) and development (completion 2023).

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A bird’s eye view of Amwaj Islands under construction

‘The vision of the developer was to create a residential resort with a recreational beach in mind’, says Dan Avendano, the original project engineer. ‘Bahrain is ironically a small island surrounded with beach - but without sand. TenCate Geotube® played an important role in making this vision a reality.’ 

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First, land with a surface area of 2.7 million m² was created. The challenge was on how reclamation could be implemented without adverse effect to the marine ecology. This concern was solved by using TenCate Geotube® technology as a containment system prior to reclamation. As a result, water turbidity and siltation have been localized within the reclamation area only. Ossis Property Developers BSC in Bahrain, one of the leading property development companies in the Gulf region, is responsible for the land reclamation. Then the infrastructure was developed (access roads, utilities, drainage, etc.).  

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Afterwards, a start could be made on constructing residential properties, service apartments, condominiums and a host of amenities such as hotels, office buildings, restaurants, recreation parks, theatres, spas, marinas and golf courses.  The island complex, which includes a theme island and an island for educational and medical facilities, caters for both young and old, and future development will include a shopping mall and an entertainment centre. Several artificial reefs have been installed around the island complex as breakwaters, reducing the wave impact by 60% and limiting the risk of damage. 

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Ossis has donated a number of artificial corral reef balls to compensate for the lost fishing ground. These corral reef balls have been placed in an undisclosed sea area

The most important element in the design, building and completion of the Amwaj Islands development project is the application of TenCate Geotube® containers, hydraulically filled with 12 million m3 of locally dredged sand, for the island perimeter. The series of containers outline the designed shape of each island. 

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Engineers from Ossis and TenCate Geosynthetics USA and EMEA were responsible for the planning and design of the container structures for the perimeter, coastline and shoreline protection, including breakwaters. The first shipment by TenCate Geosynthetics to the project site was in April 2001, the first TenCate Geotube® container installed on May 11, 2001. 

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In this region, more major island projects are in the offing, so Ossis attached great importance to delivering its project first. This required the construction of a peripheral dyke over 22 kilometres long to enclose the 12 million m3 sand for the island. In view of the time available (18 months) and the cost, the traditional riprap-based construction method was dropped in favour of TenCate Geotube®, a more efficient solution. Some 42 linear kilometres of TenCate Geotube® units were needed for constructing the perimeter, the connecting causeway, the primary erosion protection and the core of the breakwaters.  

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Tom Stephens (Commercial Director Latin American of TenCate Geosynthetics / Water & Environment) worked with the Kanoo family in the development of the project, with Mario Santiago (project manager) and Dan Avendano, the original project engineer to develop the design, the installation methodology, and project execution almost constantly for two years. Saud Kanoo is the Chairman of Ossis Property Developers BSC and the Chief Executive Officer and Deputy Chairman of Yusuf Bin Ahmed Kanoo WLL (Property Company), one of the largest independent family owned groups of companies in the Middle East with interests in shipping, travel, machinery, logistics and insurance among others. 

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According to project manager Mario Santiago, not only did the application of TenCate Geotube® technology contribute to the efficiency of the construction, it also turned out to be 50% cheaper than the original quotation specifying the traditional rock-based method. An additional advantage is the minor impact on the environment: the aquatic habitat surrounding the site. Turbidity is scarce and little silting has taken place. ‘The TenCate Geotube® technology and technical support were essential to our success in developing the project ahead of schedule and under budget,’ confirms Ossis Property Developers. 

For Tom Stephens, ‘the success of this project has been one of the most gratifying achievements and highlights of my 35 years at TenCate’. 

Watch the promotional video of the islands.

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