Since start of the project early 2015 every autumn permeable structures are constructed by the local community and a lot is learned by doing that and monitoring the construction and the effects afterwards. As natural materials are used, they degrade due to species and rotting. Frequent inspection and maintenance are required. The structures dampen wave energy, they are not strong enough to act as breakwaters. Large land subsidence is a threat to this solution as it creates a continuous setback. The Indonesian ministry of Marine Affairs and Fisheries is active in replicating this measure at other locations in Indonesia. This requires close contact with them to select suitable locations and develop adjustments to the design.
The Building with Nature measures implemented have in principle been successful.
The challenges in Demak emphasize the need for holistic solutions like Building with Nature, in combination with integrated water resources and coastal zone management.
Hence, the project will increase efforts regarding mainstreaming Building with Nature across Indonesia, including through capacity building and training.
In phases, 9 kilometres of permeable structures have been built, of which 4,4 km by government partner MMAF, preventing further erosion of the heavily subsiding area. The ownership as well as the maintenance of the permeable structures were officially transferred to the communities.
Best practices have been introduced to revitalise aquaculture productivity, boosting productivity and tripling income. Best practices are implemented by farmers in no less than 422 hectares of ponds. Through the biorights financial incentive mechanism the allocation of 70 ha (degraded) ponds for rehabilitation into coastal and riverine mangrove has been leveraged.
For the first time in Indonesia the innovative mixed mangrove-aquaculture system was introduced, in which part of the pond is given up to make space for riverine mangroves. In this system the aquaculture productivity is optimal, while the surrounding mangroves purify water and enhance fisheries.
Field studies indicate that fisheries are recovering along with mangrove recovery in the area, providing an extra source of income.
Village development plans and regulations on land use rights, protected areas and coastal zone management were developed and adopted by 10 communities and formalised with local government. It has already resulted in enhanced government support and district/village budget allocation for maintenance of permeable structures, mangrove rehabilitation and aquaculture.