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Building with Nature: a natural solution for Java

On the Indonesian island of Java, the rising sea level is threatening the lives of millions of people. To find a solution, a unique public-private partnership in the Netherlands and Indonesia was set up, with support from the Sustainable Water Fund (FDW). By building permeable dams, this project is bringing back the mangrove forests. Mangrove forests are a form of coastal protection that is both effective and all-natural. The first results are already visible.

Natural coastal protection

Mangrove forests provide natural coastal protection. The roots of the trees grow in the water and break tall waves. The trees act as a storm barrier and secure sediment, about 8cm per year. For the people living on the Javanese coast, the mangroves mostly just took up space. They cut down the forests to grow rice. Later, they used the area for shrimp and fish farming. Because of erosion, kilometres of the coastline is now gone. Today, the survival of 30 million Javanese people living in coastal areas demands quick action to secure coastal protection. Together with other parties, Ecoshape and partnering Wetlands International started a project to bring back the mangrove forests. Other major partners in the project are ministries, consultancy firms and knowledge institutions.

Building with Nature

EcoShape programme manager Fokko van der Goot believes that the public-private partnership has successfully applied the Building with Nature concept in practice. “We are building small, water-permeable dams on Java. The dams filter sediment from the seawater, creating a fertile environment for mangrove trees.”

Femke Tonneijck, Programme Manager Coastal Wetlands at the NGO Wetlands International, explains that they are involving the local communities and government authorities in the project as well. “To prevent the locals from going back to cutting down mangroves, we are helping the shrimp farmers increase their productivity. One project partner is the Indonesian NGO Blue Forests, which organises ‘coastal field schools’. These are practical training programmes aimed at teaching fish farmers more sustainable methods of aquaculture that also increase yields.”

Government participation

Government policy is also needed to help protect the mangroves through the Building with Nature programme. Tonneijck: “Luckily, the Ministries of Maritime Affairs & Fisheries and Infrastructure & Housing [public partners in the project, eds.] fully support the project. They are eager to learn from our method, and we are eager to learn from their experience. They are co-investors and have even built dams. This will enable them to continue the work on their own after our project has ended.”

The project enjoys a broad base of support. Besides Ecoshape, the stakeholder NGOs and the Indonesian government, several other parties are involved. These include the Deltares knowledge institution and Witteveen+Bos for design and installation, Wageningen University & Research for aquaculture, and Delft University of Technology and UNESCO IHE for the training programmes.

Encouraging results

So far, 9 kilometres of dams have been built. 4.4 kilometres of these dams were constructed by the Ministry of Maritime Affairs & Fisheries (MMAF), one of the government partners.  Van der Goot: “Our goal is to show that the dams work at different locations along the 20-kilometre coastline and that a new, sustainable method of shrimp and fish farming is profitable.”

The situation in 2030 if no action is taken

Ideal scenario in 2030 if coastal protection efforts continue

The project will continue until the end of 2020. So far, it has enabled the dams to capture large amounts of sediment. As a result, erosion has stopped at many places along the coast. This is a huge win for the villagers in this area. The project also shows promise for helping other coastal villages in northern Java. New mangrove plants are growing all over the place. A National Road Map for addressing and managing soil subsidence has been drafted together with the local government.

Soil subsidence is preventing the recovery of mangroves in the villages, especially near the city Semarang. This is largely the result of large-scale water extraction. Still, the Building with Nature measures are effective in delaying the impact of the subsidence.

Triple yields

Tonneijck also sees positive signs from further inland. Best practices have been introduced across 422 hectares. Tonneijck: “This has allowed us to improve both sustainability and productivity. Shrimp farmers have seen their yields triple and their incomes double.” Farmers have given up 70 hectares of aquaculture ponds along the coast and the riverbank for the mangroves to recover.

Van der Goot: “We are also quite interested in the social aspects of the project. Contractors, for example, are taking on more and more responsibility to communicate with stakeholders in the area around construction projects. In Indonesia, we are working with various sectors and local communities. We are learning a lot from that.”

Sustainable Water Fund (FDW)

The Netherlands Enterprise Agency uses the Sustainable Water Fund (FDW) to stimulate public-private collaboration in the water sector on behalf of the Ministry of Foreign Affairs.