Protecting subsiding Jakarta against floods
A consortium headed by Witteveen+Bos (main contractor) and Grontmij is developing a master plan to protect the Indonesian capital of Jakarta against major floods from the sea. The master plan is due to be ready two years from now and will put forward solutions for the short, medium and long term issues facing the city. The other members of the consortium are KuiperCompagnons, Deltares, Ecorys and Triple-A (subcontractors).
Year-on-year the northern part of Jakarta is sinking by up to 17 centimetres due to the large-scale extraction of groundwater. This part of the city lies below sea level and is regularly hit by serious flooding from the sea and rivers. Soil subsidence will increase the floods in the coming years and affect a larger part of the city.
The Netherlands is supporting Jakarta’s fight-back against flooding as part of the Water Mondiaal programme being carried out by NL Agency. Production of the Jakarta Coastal Development Strategy (JCDS) is one of the spearheads of the programme. The problems that need to be addressed were identified in the JCDS project over the past few years and solutions have now been formulated in broad terms. Discontinuation of the extraction of groundwater has been designated as a spearhead and the seaward expansion of Jakarta by means of a system of polders has been included as a medium-term solution. These solutions are going to be worked out in more detail in the coming phase of the master plan with funding from the Dutch Ministry of Foreign Affairs.
One of the spearheads of the approach adopted by the consortium is the uniting of measures for water management and other socio-economic functions. One possibility is to use new and heavier dikes to relieve the strain on the overloaded road network. Similarly, the sea defences can be combined with a seaward expansion of the seaport. The master plan will elaborate and examine these combined opportunities. Once it is ready the master plan will be carried out by the Indonesian Project Implementation Unit. The Netherlands is supporting the start-up of this unit.