The project

Mangroves provide natural coastal protection. Unfortunately, they are disappearing rapidly at the global scale, generally being pushed out by aquaculture. We can stop coastal erosion and provide better protection by using nature more. Deltares has teamed up with various partners on a range of pilot projects to restore mangroves. That involves building dam structures from natural materials near the shoreline. They capture sediment, recreating the natural habitat required for mangroves, which then get the opportunity to grow back, restoring the natural coastal protection.

Our role in Indonesia and the results

Back in 2010, Deltares experts came up with an unusual, tropical version of the mediaeval Dutch approach to salt-marsh management. They implemented it successfully. The initial promising results - 0.5 m of sedimentation in 4 months - led in 2014 to the launch of a new, large-scale project for a period of five years with the aim of using this method to protect a few kilometres of coastline in Demak, Central Java. That is urgently needed because, by 2100, sea-level rise could cause flooding in Demak up to 6 km land inwards. That would submerge 14,700 hectares of land and dramatically affect the lives of 70,000 people. The area of the mangrove forest is expected to increase to 90 hectares by 2020.

Deltares experts

Bregje van Wesenbeeck, expert salt-marsh

This really is the jewel in the crown of our pioneering work. And it is nice to see how other countries, such as the Philippines, are now getting interested.

Han Winterwerp, expert sediment

If this turns out to be a success, we have a template that will allow us to make life better and safer for many, usually poorer, people in the world.