Establishing Mangrove Belt to Combat Coastal Flooding in Indonesia

CHALLENGE

Pekalongan City, faces worsening coastal flooding due to sea level rise, land subsidence, and tidal events, damaging paddy fields, fish ponds and roads, and disrupting local livelihoods.

SOLUTION

The 3S Project strengthens community resilience through ecosystem-based adaptation, establishing a 6-km mangrove belt, breakwaters, and sustainable livelihood initiatives.

OVERVIEW

Pekalongan City in Central Java, Indonesia, suffers from repeated flooding due to rising sea levels, land subsidence, and tidal surges that damage farmland, fish ponds, and road networks while increasing health risks of waterborne diseases. To address these challenges, the Safekeeping–Surviving–Sustaining (3S) towards Resilience Project (2021-2026), led by the non-profit organization Kemitraan with support from the Adaptation Fund, applies ecosystem-based adaptation approaches. The project restores coastal protection by constructing breakwaters and wave deflection berms that encourage beach sediment recovery, where mangroves are replanted to reduce erosion and flooding. Mangroves provide habitats for commercially valuable species, support eco-tourism, and enable local Batik producers to use mangrove-based natural dyes—enhancing livelihoods, creating new income opportunities, and building long-term resilience for the community.

DETAILS

The coastal area of Pekalongan City in Central Java is one of the most vulnerable regions impacted by sea level rise in Indonesia. The sea level in this area increases by about 6-10 mm annually (Suhelmi, 2012; Syam et. al., 2021; Andari et. al., 2023). This rise, combined with land subsidence and tidal flooding, has led to frequent, sometimes permanent, inundation, coastal erosion, and increased saltwater intrusion. In 2014, flash floods and coastal flooding inundated over 40,000 hectares of paddy fields and damaged thousands of hectares of fish ponds (Kompas, 2014). In 2016, coastal flooding submerged major roadways under 50-120 cm of water. Over the past decade, communities, especially those in the northern part of the city, have experienced coastal flooding daily (Kompas 2016). In addition to damaging paddy fields, freshwater ponds, and road networks, the flooding has also harmed housing, drainage systems, and ports. This complex combination of tidal flooding, inundation, and infrastructure damage imposes significant economic losses on farmers and fishermen, disrupts logistics for industries around the city, and increases the risk of water-borne diseases.

Supported by the Adaptation Fund, Kemitraan is employing the Safekeeping-Surviving-Sustaining (3S) concept to build community resilience against coastal flooding. The 3S project aims to enhance community disaster resilience by improving physical infrastructure and developing institutional capacity across multiple levels of governance. One of the solutions offered is the establishment of a mangrove ecosystem, which acts as physical infrastructure against coastal flooding, builds community resilience, and provides economic benefits. The project plans to establish a 6-km mangrove ecosystem to provide coastal protection and alternative livelihoods for farmers and fishermen, as well as improve the city’s mangrove eco-tourism potential and offer a natural dyeing source for the Batik industry.

Establishing physical infrastructure and reclaiming the shore

Breakwaters and wave deflection berms made of concrete and rock are being constructed through the 3S project and strategically spaced offshore. These structures are designed to create natural breakwaters and restore beach sediment. Mangrove seedlings are then planted in the restored sediment. To increase the survival rate of these seedlings, the project employs an innovative approach called “bumbung,” which uses protective bamboo shields with side cut-outs. These shields elevate the mangrove seedlings, preventing them from being washed away during high tides and floods.

Increasing community resilience by extending the mangrove belt

The project aims to extend the existing mangrove belt to benefit vulnerable communities in three villages in northern Pekalongan city: Panjang Wetan, Kandang Panjang, and Bandengan. Mangroves serve as sediment traps, protect against coastal erosion, act as natural barriers against flooding, and support ecosystems with commercially valuable fish, shrimp, prawns, and crabs. These species, in turn, provide alternative income for the target communities.

Mangrove aquafarming for generating alternative income

The extension of the mangrove belt aims to introduce alternative options for communities vulnerable to coastal flooding. These communities in Pekalongan city rely economically on small-scale industries, such as kiosks selling daily necessity, Batik processing, paddy farming, and fisheries. Coastal floods disrupt their livelihoods, forcing kiosks to close and damaging paddy fields. Farmers cannot work on waterlogged land, and floods affect the Batik drying process, often damaging the quality and colors. Fisheries are indirectly impacted as well, with reduced fish populations near the shore, requiring fishermen to venture further out to sea. This decrease in fish catches has a ripple effect on those supporting the fishing industry, such as porters and ice suppliers. The decreasing amount of fish catches decreases the amount of required labor (porters) to transport the fish from ship to the nearby fish market or storage facilities.

The alternative livelihood strategy relies on a healthy and well-conserved mangrove ecosystem, which can serve not only as a source of livelihood for fishermen but also as a destination for recreational fishing. The 3S project is assisting the target community in developing a more resilient and sustainable livelihood strategy. The project also seeks to innovate by developing mangrove-based natural dye products.

PROJECT DETAILS

• Location: Pekalongan, Indonesia

• Funding: The Adaptation Fund

• Grant Amount: USD 5,972,670

• Duration: 2021-2026

ACKNOWLEDGEMENTS

This article was reported by Faris Salman of Institute for Global Environmental Strategies (IGES) and draws on the comprehensive work of Kemitraan and the Adaptation Fund, as detailed in their report on the coastal resilience project in Pekalongan City. AP-PLAT expresses sincere gratitude to the original contributors for their valuable insights and findings, and to Faris Salman for preparing this article.

RELATED INFORMATION

Project report on Adaptation Fund:
Safekeeping-Surviving-Sustaining towards Resilience: 3S Approach to Build Coastal City Resilience to Climate Change Impacts and Natural Disasters in Pekalongan City, Central Java Province – Adaptation Fund

Press release about the project:
Fighting Rising Seas and Sinking Lands in Indonesia with Adaptation Resolve and Ingenuity

Andari, L., Sugianto, D. N., Wirasatriya, A., & Ginanjar, S. (2023). Identification of sea level rise and land subsidence based on Sentinel 1 data in the coastal city of Pekalongan, Central Java, Indonesia. Jurnal Kelautan Tropis, 26(2), 329–339. https://doi.org/10.14710/jkt.v26i2.18324

Syam, D. A., Laksita Wengi, K. R., & Gandapurnama, A. (2021). Climate Risk and Impact Assessment of Pekalongan, Indonesia. In Technical Working Report. Mercy Corps Indonesia. https://www.mercycorps.or.id/sites/default/files/dokumen/Climate%20risk%20and%20impact%20assessement_Pekalongan_MercyCorpsIndonesia_final.pdf

Suhelmi, I. R. (2012). Valuating Semarang Coastal Vulnerability Due To Sea Level Rise Using Composit Vulnerability Index. Jurnal Segara, 8(2). https://doi.org/10.15578/segara.v8i2.173

Kompas.com. (2014, February 10). Produksi Pangan Makin Terancam. Kompas. https://biz.kompas.com/read/2014/02/10/17082928633/Produksi.pangan.Makin.Terancam