Indonesia to build a giant sea wall. It is meant to protect Java from rising sea levels

Can the power of the sea be stopped? Indonesian authorities believe that only tons of concrete stretching across kilometers of coastline can withstand the force of ocean waves. Construction of a gigantic structure designed to hold back water pushing inland is set to begin later this year on Java, the country’s most populous island. Will the sea wall bring more benefits than harm?

Protection from water for the environment and residents

Flooding on Java, one of Indonesia’s largest and most densely populated islands, is a common occurrence. It results from the region’s rapid development, dense urbanization, numerous construction projects along the coast, and the destruction of mangrove forests.

However, coastal degradation is not the only problem. Flooding on Java also has a severe impact on residents’ quality of life. Water regularly inundates homes, industrial areas, ports, and farmland. This creates serious threats, including recurring food shortages.

Agus Harimurti Yudhoyono, the minister of infrastructure and regional development, explained the reasoning behind the investment as follows: This is not just about a sea wall. It is about securing our country’s future economy and the safety of our people.

Indonesia has a long history of dealing with floods. Until now, authorities have relied on simpler solutions such as dredging rivers and building canals and flood embankments. However, the increasingly severe inundation of the island means these methods are no longer sufficient.

What will the sea wall in Java look like?

The planned sea wall will have a total length of 575 km. The structure will be built from concrete and divided into 15 sections, which will be further segmented. This is intended to prevent coastal degradation and land subsidence.

Construction work is expected to begin as early as September 2026. However, the project is not expected to be completed quickly. Experts say the construction of the sea wall could take decades.

Indonesia’s flagship project has been valued at 80 billion dollars. Funding will come from the national budget as well as, according to the local outlet The Jakarta Post, public-private partnerships involving entities from the United Arab Emirates.

What if not a wall?

The idea of building a concrete wall along the Indonesian coastline has sparked justified controversy. Representatives of local communities and academics emphasize that the project involves enormous costs. It will also require vast amounts of sand. The sea wall could additionally threaten mangrove forests and worsen living conditions for Java residents who rely on fishing for their livelihoods.

Experts, including the authors of a Deloitte report on Indonesia’s sea wall, as well as representatives of civil society, do not reject the idea of the wall itself. They point out that such a structure could effectively protect against floods and provide safety for residents and infrastructure. However, they suggest approaching the issue in a more systemic and flexible way.

In their view, the construction of the sea wall should be accompanied by other measures, including river cleanups and nature-based solutions such as restoring coastal ecosystems, planting mangrove forests, and rehabilitating wetlands and floodplains. Consultations with local communities regarding new proposals are also considered extremely important.

At present, it appears that Indonesia’s massive investment project will begin as planned within the next few months. It will probably not completely stop the floods affecting Java, but it may reduce their negative impacts. Time will show at what cost.