Building with Nature for safe, prosperous and adaptive coastlines in Indonesia

Full Solution
Securing eroding delta coastlines
Photo by INFIS

The solution increases resilience along 20km of eroding delta coastlines, combining civil engineering with mangrove rehabilitation to build safe and adaptive coastlines and by introducing sustainable land use. Technical measures include sediment balance restoration by using permeable dams and mud nourishments and mangrove rehabilitation. Socio-economic measures include development and introduction of sustainable aquaculture and livelihoods diversification (e.g seaweed cultivation, crab, shrimp)

Last update: 27 Oct 2022
Challenges addressed
Land and Forest degradation
Sea level rise
Storm surges
Tsunami/tidal wave
Lack of alternative income opportunities
Changes in socio-cultural context
Poor governance and participation

Coastal floods are increasing and have destroyed infrastructure and productive land. Salt water intrusion pollutes drinking water, reduces aquaculture profits and affects agriculture. Over the last decade income has decreased for shrimp farmers and fishermen respectively. This decline in well-being, security and self-reliance has been further exacerbated by the collapse of natural resources – timber, fuel, fish – which used to account for more than 50% of their income. Coastal managers typically use “hard” engineered solutions to combat erosion problems and related hazards which do provide important protection but are too expensive and complicated to design along muddy coasts. They do not address the root causes and fail to restore environmental conditions that are crucial for a productive aquaculture and fisheries sector. Large scale mangrove planting efforts have failed, hampered by erosion and wave action. Protection measures are implemented ad hoc without coherent strategy.

Scale of implementation
Coastal forest
Disaster risk reduction
Sustainable livelihoods
Local actors
Coastal and marine spatial management
Fisheries and aquaculture
Demak, Central Java Province, Indonesia
Southeast Asia
Summary of the process

The construction of permeable dam structures as sediment traps as building block 1 is a precondition for mangrove rehabilitation and coastal zone stabilization. Socio-economic measures to promote sustainable land use options (building block 2) provides local communities with short- and medium-term revenues to compensate previous losses and is a key element to ensure the long-term efforts under building block 1. Capacity building measures (building block 3) provide involved stakeholders with the relevant technical know-how to engage in this initiative while the policy dialogue between different governance levels (building block 4) is essential to integrate this solution in the long-term policy and planning frameworks of the district and province.

Building Blocks
Construction of permeable dam structures as sediment traps and basis for mangrove rehabilitation
Technical measures to protect the coastline in Demak include restoration of the sediment balance using permeable dams and mud nourishments, alongside mangrove rehabilitation. – Grids of permeable dams are put in place to dampen erosive waves and to trap sediments, so that the disturbed soil profile is restored; – In this sheltered environment mangrove forests are rehabilitated. The mangroves stabilize sediment, further build up the soil and protect against salt water intrusion and flooding; This process is reinforced in the most severely degraded sites through sustainable sediment suppletions. Where needed agitation dredging and nourishment of sand banks may help shape the soil profile and shelter vulnerable parts of the coast.
Enabling factors
Ownership and provisions for maintenance of the structures will be formalized during the project in co-management arrangements between communities and the local government. Communities will take full ownership over the structures ensuring their long-term maintenance. Maintenance costs will be covered via community-managed development funds.
Lesson learned
The set-up was successful: we were able to trap up to 45 cm of mud and there are already Avicennia mangrove juveniles of 50 cm tall within 1.5 years. Some of the poles were damaged by shipworms and brushwood is disappearing – leading to the collapse of part of the dams during storm events. Some structures were damaged during the monsoon season. The pilot hence did its job: trapping sediment and the principle of the design is sound. We are now testing the best materials to use, for optimizing our design and providing lessons learned for scaling up. Other key lessons: place the poles deep enough, use sufficient fill material, add material frequently and keep the ropes really tight. We are developing guidelines on ‘permeable structures‘ to trap sediment for mangroves recovery as stakeholders want to replicate the approach Upcoming topics include system understanding, community planning, fish pond rehabilitation, mud nourishment and ecological mangrove rehabilitation (EMR).
Socio-economic measures to promote sustainable land-use
This building block includes development and introduction of sustainable aquaculture and livelihoods diversification (seaweed cultivation, crab & shrimp farming). –10 community groups are supported through farmer field schools and by providing resources to initiate new aquaculture management practices and livelihood diversification. –these improved practices will directly revitalize 300 ha of land for 300 households (based on a conservative estimate of 1 ha per household), increasing average aquaculture productivity with 50%, by adjusting pond lay-out and management, by reducing fertilizer and pesticide inputs, by making optimal use of mangrove services like water purification and by diversifying livelihoods activities. Based on experiences in Indonesia and Vietnam, income derived from the ponds is expected to have risen to 5000 EUR ha by year 5. –community funds will be established that: i) absorb savings from increased pond productivity (5%) in support of long-term coastal belt maintenance and up-scaling of sustainable land-use management measures beyond the project lifetime; ii) can absorb government support to local communities for coastal protection and sustainable land-use.
Enabling factors
Communities have full ownership over enhanced aquaculture production systems and the hardware that will be put in place during and after the project. The reclaimed land will be managed as community-based protected areas (as agreed between communities and the local government), with opportunities for sustainable use of natural resources. The reclaimed mangrove belt will be formally owned by the government as per Indonesian law.
Lesson learned
to be added later
Capacity building on “Building with Nature solutions”, targeted at government officials, private sector, students and local communities
Enhanced capacity and awareness is required to enable and stimulate the target group and other actors to take an active role in planning and implementation of Building measures. Three different training curricula will be developed and delivered, targeting government, private sector and communities. Trainings will address both technical (e.g. rehabilitation of mangroves, construction of permeable dams), socio-economic (e.g. improved aquaculture; livelihoods diversification) and institutional (ICZM, group organising etc.) matters.
Enabling factors
We apply an adaptive learning-by-doing capacity development strategy that is updated frequently with lessons learned. Monitoring of the recovery of the coastal systems is crucial. Instructions for the design, construction, and supervision of the project implementation are therefore continuously updated. Capacity building activities include courses and practical training, where trainees learn the Building with Nature philosophy and apply its concepts.
Lesson learned
–Government: 100 people (p.) from district, provincial and national government agencies (fisheries service, water management service, forestry service, environmental agency, public works, secretariat office, production bureau, mangrove working group) will be trained on the applicability of the solution. After the training agencies are able to further internalize the approach in sectoral and integral coastal zone planning; 500 p reached through Training of Trainers approach. –Private sector: 50 p. from Indonesian engineering firms will be trained on the design and implementation of the solution. They will be able to design and execute Building with Nature measures and weigh these against conventional design solutions. 250 p. reached through Training of Trainers approach. –Communities: 250 p. from 10 communities will be trained in the implementation and maintenance of Building with Nature measures; Farmer field school activities indirectly reach all inhabitants in the 10 communities.
Policy dialogue to develop governance arrangements for improved coastal zone management
Key impediments to sustainable lowland development are the lack of integration of coastal zone management policies and approaches, and limited translation into practice and limited community engagement during design and implementation of plans. The Indonesian government has embarked on various integrated master planning processes and established taskforces and working groups to address these challenges. A large proportion of the solution is dedicated to supporting this policy dialogue process, creating an enabling environment. At community level, project partners have been invited by the target communities to facilitate the development of 10 year village development plans and regulations that guide resources management. These will define ambitions for sustainable aquaculture and coastal security. Community-village plans will contribute to implementation of the provincial master plan, addressing community priorities and needs. This alignment greatly increases community ownership with regards to decision making and engagement in implementation of development plans. After the project, representatives of all 10 target communities will have actively become involved in government-led planning.
Enabling factors
-Close collaboration with government partners and other players at different policy levels -A thorough policy analysis on where and how to embed measures in national and subnational policies and budgets e.g. (spatial) development plans, master plans, coastal zonation plans, mangrove strategies, greenbelt and forest legislation, NDC, NAP, DRR (Sendai Framework) and SDG Community plans: We will facilitate village planning discussions in 9 villages about problems, root causes and solutions.
Lesson learned
Tangible results: –Master plan for sustainable development of Demak district - including Building with Nature Indonesia measures - developed with and endorsed by Taskforce Integrated Coastal Zone Management led by planning agency of Central Java and involving all relevant stakeholders. –Master plan and Building with Nature approach embedded in Central Java Provincial policies (spatial plan and mid-term development plan 2019-2024 and provincial mangrove strategy). Village development plans and regulations on land use rights, protected areas and coastal zone management developed and adopted by 10 communities and formalised with local government.

Coastal security, safety, economic growth and self-reliance of 70.000 vulnerable farmers and fishermen in Demak is enhanced by avoiding further coastal flooding and erosion and providing them with a long term perspective for sustainable economic development. The combination of permeable dams and mangroves protect the villages against storm events. The convincing results of Building with Nature are used to create safer deltas in developing countries, contributing to sustainable inclusive economic growth and poverty reduction and more self-reliance. Extensive stakeholder dialogue and capacity building allow the integration of measures in community development plans and integral government master planning and governed under community bylaws and funding mechanisms This flagship project is used to inform and inspire coastal zone managers from government and private sector and help them include the approach in their urban and rural development programmes. A replication and up-scaling of Building with Nature across Indonesia could indirectly result in increased resilience of 30 million people in Java who are on the long term at risk from coastal hazards, in both urban and rural areas.


People in Demak District and when the approach can be scaled up to the entire coastline of Central Java, it can help 30million people that will in the long term suffer from coastal flooding and erosion hazards in Northern Java (3000 villages).

Sustainable Development Goals
SDG 11 – Sustainable cities and communities
SDG 13 – Climate action
SDG 14 – Life below water
Photo by Nanang Sujana
Villagers in Demak happy with demarcation protected mangrove zone
Photo by Nanang Sujana

The people in Demak district, 70.000 farmers and fishermen, along the North coast of Java are desperate: in just 10 years’ time their valuable lands have washed away by the sea. They lost their roads and schools. Entire villages disappeared into the water, as the sea encroached up to 3 kilometers inland, claiming over 1000 ha already. Northern Java’s deltaic shorelines suffer from severe erosion and related flooding hazards, caused by mangrove conversion for aquaculture, groundwater extraction and infrastructure development. In some places kilometers of land are already lost. As a result, over 30 million people in Java are at risk. The agri- and aquaculture sectors have suffered multi-billion losses. Conventional hard-infrastructure solutions are ineffective, expensive and unable to adapt to climate change. They fail to bring back economic, environmental and social benefits that healthy mangrove coastlines offer. Timbul Sloko is the pilot site of Building with Nature Indonesia. There seemed to be no means of stopping the erosion and the floods. Major investments were made in seawalls and wave barriers, but all these efforts failed. Mangrove replanting was also not successful as the conditions were not right, such as the input of sufficient sediment. The floods kept on creeping further into the village and taking the land by 100 meters every year. People became desperate and made plans to move away, having witnessed neighbouring villages already being swallowed by the sea. But then a new solution was introduced in the village, called “Building with Nature”. This solution entails the placement of permeable dams (see picture). The permeable dams break the waves and trap sediment thus reclaiming land. Once the land is back, mangroves can recolonize the area and help protect the coastline against erosion. The large scale building with Nature project provides coastal security and supports sustainable revitalization of 6000ha of aquaculture ponds along a 20 km shoreline Now the waves are clearly much lower inside the grid of permeable dams than outside. In some cases, pioneering mangrove trees are already testing the ground. A major breakthrough came when the village signed a decree, demarcating 100 ha of the currently lost land as protected area. This means that once the mangrove belt is restored, it will not suffer the same fate again. The potential and hope is created for a new landscape in which mangroves and aquaculture can be combined sustainably.

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