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Kapuk Naga Indah project in good shape

After 15 years of preliminary, conceptual and detailed designs, advice on tender documents and assistance by Witteveen+Bos in obtaining permits, construction of the first Kapuk Naga Indah (KNI) island in Jakarta Bay started in 2012. The artificial island has almost reached its final shape, and engineering services are now being provided in the form of technical assistance. Reclaiming land for a polder system from the more than 10-metre-thick layer of soft soil in Jakarta Bay has turned out to be quite a challenge.

Involvement of Witteveen+Bos

Witteveen+Bos Indonesia has been providing consultancy services for the project since the initial stages in 1982. During that period, valuable experience has been gained in tackling the many challenges that reclaiming land in Jakarta Bay entails. With a surface area of 300 hectares and fulltime contributions from ten experienced engineers in both Jakarta and the Netherlands since 2012, this is one of the biggest land reclamation projects that Witteveen+Bos Indonesia has ever worked on. The scope of the work continues to expand, with conceptual designs for new reclamation projects still being produced.

Flexibility

Whereas technical assistance is usually very strictly defined, flexibility is a basic requirement in the case of the KNI islands. The construction work on most of the islands has been awarded to a contractor that has gained all its experience in land reclamation as part of the current project. This does not always result in the exact construction that we, as the designer, would prefer. This situation requires careful supervision and a highly alert technical assistance team. Aside from the technical challenges, commercial developments and governmental guidelines that are subject to continuous change require frequent design modifications, even while construction is ongoing.

Advanced modelling has been used to properly identify risks and the responses of the design. Calculation methods comprising advanced dynamic FEM modelling provide insight into the behaviour of sea defences during earthquake events. The water quality in the river mouths in Jakarta Bay is being investigated for future utilities to be installed on the islands, and a large-scale permanent network has been set up to perform land subsidence measurements.

During the technical assistance phase, a huge volume of monitoring data will provide insight into the actual behaviour and the build-up of the land reclamation during construction. Witteveen+Bos has set up a sophisticated WebGIS system that provides weekly overviews of all data, their location, and the history of the project. This enables us and the client to anticipate potential deviations.

+ tom.wilms@witteveenbos.com