Is it true that Jakarta is experiencing subsidence?

This is the Waladuna Mosque located in Jakarta, which currently exhibits a dilapidated roof, walls covered in moss, and inundation of seawater in every corner. The last instance of prayer within its walls dates back to 2001, when it was still above ground. Presently, it serves as a warning sign, indicative of the potential fate of Indonesia's capital city if prompt action is not taken. Despite facing similar rising sea levels as other coastal cities worldwide, Jakarta's situation is unique. The city has been sinking for several decades, as evidenced by the blue areas that depict the extent of its descent since the 1970s.

The darker the area, the greater the drop. The majority of sinking occurs in the north coast, where Jakarta meets the Java Sea, with the land sinking by approximately 25 cm annually. This destabilizes the area, causing damage to homes and disrupting the lives of residents, particularly those who rely on fishing for their livelihoods. However, even those residing further inland, among Jakarta's population of over 10 million, are at risk. By 2050, a significant portion of Jakarta, including the residences of millions of individuals, may be submerged underwater. This is due to the fact that Jakarta is situated on a low-lying coastal area on a swampy plain, with 13 rivers flowing through it. However, the primary reason for the city's sinking is the lack of access to sufficient water for its inhabitants.

The majority of Jakartans do not have access to clean, piped water, and instead rely on wells for their water supply. These wells extract water from aquifers, which are underground rock layers that hold groundwater. The porous spaces within the rock are filled with water, and the constant extraction of this water by millions of individuals has caused the soil to compact and collapse, resulting in the sinking of the ground above it.

While aquifers are typically replenished naturally through rainfall, this is becoming increasingly rare in Jakarta due to the city's rapid development and extensive concrete coverage. This has resulted in flooding in coastal areas, such as the fishing community of Muara Baru, where makeshift bridges have been constructed to navigate the flooded neighborhoods. The combination of sinking ground and rising sea levels has made floods during high tide and rainy seasons even more dangerous.

Jakarta has experienced devastating floods in the past, such as in 2007, when a storm and high tide caused rivers and canals to overflow, resulting in the loss of 80 lives. The sinking ground has already caused individuals like Maksim to lose their homes, and Nondho has had to rebuild his home multiple times.

The survival of Jakarta is at risk due to the excessive pumping of groundwater. However, to understand how the city arrived at this situation, one must look back centuries to the Dutch colonization of the area in the 1600s. The Dutch razed the original port town of Jayakarta and built Batavia, a city in the Dutch style, displacing the indigenous Indonesian, Chinese, Indian, and Arab populations who had lived there for centuries.

The canals of Batavia served multiple purposes, including trade, defense, and the creation of a Dutch atmosphere. However, upon observing the city from an aerial perspective, it becomes apparent that the city grid was also designed to serve a more sinister purpose. A closer examination reveals a lack of bridges connecting the various sections and blocks of the city, a deliberate strategy employed by the outnumbered Dutch to control the local population. This resulted in the confinement of different groups to their respective city quarters, a system that persisted for over a century until the mid-1700s.

The deterioration of the canals due to poor maintenance and sediment blockages from earthquakes led to the spread of disease and the migration of wealthier Dutch to the south of Batavia, where a new colonial administrative center was established. Despite the deadly consequences of the stagnant water, the Dutch continued to neglect the canals and instead focused on developing a centralized water supply system with iron pipes to distribute clean drinking water and indoor bathrooms. However, this system was concentrated in areas where the Dutch had relocated, leaving the indigenous population in informal settlements known as "kampongs" far from the piped water.

This created a new division in the city, with native residents forced to rely on street vendors or the neglected canals for water. It took several decades before pipes were finally installed in these communities, and even then, only a few public standpipes were provided. The year 1949 marked the continuation of a significant event in Indonesia's history. Following an armed conflict, the Dutch eventually acknowledged Indonesia's independence and withdrew from the country. However, their departure left behind a sprawling city constructed on marshland and segregated by water access, which the Jakartans had to contend with. Over the ensuing decades, Jakarta's population grew exponentially, necessitating more housing, stores, and streets, resulting in rapid expansion. Despite this, the city's water infrastructure still fails to serve the majority of its inhabitants. A chart depicting the percentage of Jakarta's population with piped water reveals that it was a mere 12% in the 1950s and remains below 50% to this day.

Consequently, many individuals without access to piped water have no alternative but to rely on roundwater pumping to survive, exacerbating the city's sinking problem. The Indonesian government has even contemplated relocating the capital from Jakarta to the neighboring island of Borneo, but this would not benefit the millions of people residing in Jakarta. To rescue the city, the government announced a project in 2014, in collaboration with a Dutch architecture firm, to construct and reinforce 120 km of seawalls to prevent water from flooding the land as it sinks. However, only 10 kilometers of the seawall, such as the one in Muara Baru, have been reinforced thus far. The issue is that, like the rest of Jakarta, the seawall is sinking.

The project encompasses a grandiose $40 billion initiative to erect a 38 km wall, fashioned in the likeness of a colossal bird, with the aim of safeguarding the coast from inundation. However, the completion of this project may require up to three decades. By that time, Jakarta may have relinquished the majority of its coastal terrain. The subsidence of Jakarta will persist until the extraction of groundwater is terminated. The government must provide an alternative to the extraction of groundwater, as has been accomplished in the past. Tokyo, Taipei, Shanghai, and Bangkok are among the cities in the region that have successfully halted their subsidence by supplying piped water. Nevertheless, time is of the essence. Jakarta has been independent of Dutch rule for slightly over 70 years. However, the Dutch's method of constructing and dividing the city, as well as restricting its water supply, continues to plague it to this day. Jakarta is sinking into the ocean, and this will remain its reality until the government devises a plan to provide its citizens with clean, piped water. This will persist for as long as Jakarta endures.