Restoring Javanese coast with mangrove forests

In March 2015 the Dutch and Indonesian governments launched a public-private collaboration aimed at improving safety along Java’s north coast by combating the rapid erosion affecting the area. With the coastline having moved as much as three kilometres inland in ten years’ time, the livelihoods and homes of 70,000 residents in the Demak region are at risk. A total of 3,000 villages and their agriculture and fisheries are threatened. The project to restore this coastline is one of the leading initiatives of the Building with Nature programme established by EcoShape and its partners, one of whom is Witteveen+Bos.

In the past few decades large parts of the mangrove forests on the north coast of Java have been cut down to make way for fish ponds or because of infrastructure or groundwater developments. This has led to extensive erosion as the coast is no longer naturally protected by the mangroves. Roads, schools, homes and fish ponds have all been lost to the sea and many residents no longer have a source of income. Artificial coastal protection has turned out to be expensive, ineffective and not climate-adaptive.

Along the 20-kilometre coastline of Demak, in an area covering 6,000 hectares, a Building with Nature pilot project has begun in which civil engineering and socio-economic measures are being combined. The civil engineering component consists of developing semipermeable dams which capture sediment and allow the mangroves to grow back. At the same time, the local population is being taught how to carry out sustainable agriculture and fishing at the Coastal Field School. Such practices will prevent the future felling of mangroves and allow the economy to benefit optimally from nature. For this project, local knowledge and networks are being united with technical expertise to ensure the relevant concepts are embedded among local residents. Due consideration is also being given to a revenue model for the local population.

The aim is for the project to be rolled out along other sections of Java’s north coast, with the long-term goal being to inspire coastal management authorities throughout the world to embed the Building with Nature approach into their policies and landscape planning. As well as contributing to the technical development of the dams, Witteveen+Bos was involved in preparing a social cost-benefit analysis to identify the advantages of the Building with Nature approach.

Building with nature

Restoring mangrove coast with semipermeable dams

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