Jakarta Sinks Deeper as Land Subsidence Worsens Flood Risks

The Capital That Is Slipping Away

The Indonesian capital of Jakarta faces an existential threat that unfolds slowly yet relentlessly beneath the feet of its ten million residents. The city is sinking, with parts of the megacity disappearing into the ground at alarming rates. According to recent assessments by the National Research and Innovation Agency (BRIN), Jakarta’s land is sinking at an average rate of 3.5 centimeters per year. This gradual descent creates a precarious situation where the city finds itself caught between falling ground and rising seas, placing millions of people and billions of dollars in infrastructure at increasing risk.

The problem is not distributed evenly across the city. Northern Jakarta bears the heaviest burden, experiencing some of the most severe impacts of this subsidence. Over the past four decades, this area has sunk by as much as 4 meters, leaving roughly 40 percent of it below sea level. The physical transformation of the landscape has turned the northern part of the city into what experts describe as a bowl, increasingly vulnerable to overflowing rivers, torrential rains, and encroaching seawater.

Jakarta’s land is sinking. The northern part is turning into a ‘bowl’ and a flood hot spot, vulnerable to overflowing rivers, torrential rains and encroaching seawater.

This warning comes from Mr. Yus Budiyono, a senior researcher at BRIN, who has studied the phenomenon extensively. The bowl-like topography creates a natural collection point for water, making each flood event potentially more devastating than the last. When heavy rains fall, water flows from higher elevations in the south into this depression, where it becomes trapped with nowhere to drain naturally.

The geography of Jakarta itself contributes to its vulnerability. The city sits on a low-lying delta where rivers from the southern highlands converge before emptying into Jakarta Bay. This natural drainage pattern once helped manage water flow through the region. However, human activities have disrupted these natural systems, compounding the challenges posed by the city’s location.

The Mathematics of Sinking

The rates of subsidence across Jakarta tell a concerning story of differential sinking. While the city-wide average stands at 3.5 centimeters annually, some areas experience far more dramatic descent. Research from IPB University shows that between 2019 and 2020, various parts of Jakarta sank at rates between 1.8 and 10.7 centimeters per year. North Jakarta consistently shows the highest subsidence rates, with estimates reaching approximately 4.9 centimeters annually.

These numbers gain perspective when compared with global averages. Jakarta is sinking by an average of 1 to 15 centimeters per year, which far exceeds the typical coastal megacity average. In some parts of North Jakarta, the ground sinks by as much as 25 centimeters every year. This dramatic rate means that some neighborhoods have descended 2.5 meters in just a decade, a transformation visible to residents and observable in the changing landscape.

The sinking happens silently but with visible consequences. In the Muara Baru district of North Jakarta, an entire office building now stands abandoned. The first-floor veranda remains functional, but the ground floor has become completely submerged. The land around the building sits higher, leaving floodwater with nowhere to drain. Similar scenes play out across the northern coast, where buildings that once stood above sea level now find their foundations below the water table.

Local residents describe these changes in tangible terms. Fishermen report observing the tide rising approximately 5 centimeters higher each year. In coastal communities, houses that once offered views of the sea now look out onto concrete dykes built in increasingly desperate attempts to hold back the ocean. The physical transformation of the city happens gradually enough that it can escape daily notice, yet the cumulative effect over years becomes impossible to ignore.

The mathematics becomes even more concerning when projections look toward the future. Studies indicate that without aggressive intervention, approximately 25 percent of Jakarta’s capital area could be submerged by 2050. The risk could potentially double or increase even further due to climate change. Heri Andreas, a researcher at the Bandung Institute of Technology who has studied Jakarta’s land subsidence for two decades, offers an even more dire prediction.

If we look at our models, by 2050 about 95% of North Jakarta will be submerged.

This projection aligns with broader research showing that subsidence-related flooding will expand by 100.5 square kilometers by 2050, potentially covering 75 percent of North Jakarta. The timeline for these predictions falls within the lifetime of many current residents, making the threat not theoretical but immediate for generations living in the city today.

The Weight of Water and Concrete

The primary driver of Jakarta’s sinking lies beneath its surface in the aquifers that have long supplied the city with water. As Jakarta has grown into a megacity of over 10 million residents, with millions more commuting in daily for work, the demand for water has increased dramatically. The city-owned piped water operator, PAM Jaya, has yet to achieve full coverage across the metropolitan area. This gap in service forces residents and businesses to turn to alternative sources.

Many Jakartans rely heavily on pumped groundwater for domestic use. Households drill wells to access freshwater underground, and industries have historically used groundwater for operations before government regulations curtailed the practice. The continuous extraction of water creates empty spaces underground. As water is removed from the aquifers, the soil above compacts and sinks, much like a deflating balloon losing its shape and volume.

The scale of groundwater extraction in Jakarta reveals itself through historical data. In 1879, only 42 groundwater wells existed within the city. By 1968, this number had increased to 352 wells. The most dramatic surge came later, with 3,626 registered groundwater wells recorded by 1998. This represents a tenfold increase in just three decades, coinciding with the period when land subsidence became a recognized problem in Jakarta.

Not all groundwater extraction contributes equally to the problem. Deep groundwater wells, which require significant investment to construct, cause more substantial subsidence than shallow wells. These deep wells are typically built by sectors with sufficient capital, such as hotels, shopping malls, and high-end residential developments. The urban poor settlements generally rely on shallower wells that have less impact on the deep geological structures.

The weight of the built environment itself contributes to the sinking problem. Jakarta has experienced rapid urban development, particularly since the 1960s. From the 1770s to the 1960s, the modern-planned built area of Jakarta grew by only 17.7 percent. However, by 2014, the modern-planned portion occupied 83.7 percent of the city’s total area, representing growth of nearly 65.5 percent in approximately five decades.

This horizontal expansion of buildings, roads, and infrastructure adds considerable weight to the land. Research suggests that about 1.68 trillion pounds of concrete, glass, and steel cover Jakarta’s landscape. Such cumulative weight can cause the ground to compress, particularly on the young sediment alluvial soils on which the city is built. The combination of excessive groundwater extraction and the weight of urban development creates a dual pressure that pushes the land downward.

The Economic Toll of Subsidence

The physical sinking of Jakarta translates directly into economic costs that affect the city, its businesses, and its residents. Mr. Yus Budiyono estimates that Jakarta loses at least US$186 million annually because of flood risks. This figure represents the current economic impact but does not account for future escalation. If subsidence continues without effective mitigation, the projected annual losses could rise to US$421 million by 2030.

These economic losses manifest through various channels. Flood damage to infrastructure consumes public resources that could otherwise fund development projects. Businesses face operational disruptions during flood events, losing productivity and revenue. Residents incur costs for property damage, evacuation, and temporary relocation. The cumulative effect drags on the city’s economic output and reduces its attractiveness for investment.

The insurance sector has begun to recognize the growing risk. Properties in subsidence-prone areas face higher premiums or may become uninsurable altogether. This dynamic can reduce property values and create a cycle where declining investment in vulnerable neighborhoods accelerates their deterioration. The economic impact therefore extends beyond immediate flood damage to affect long-term property markets and urban development patterns.

Infrastructure maintenance represents another significant cost category. As the ground sinks, buildings develop cracks in foundations and walls. Roads require more frequent repairs as their surfaces shift and become uneven. Utility pipes, once buried at standard depths, can become exposed or damaged as the land around them descends. Fortuna Sophia, a resident of a luxurious villa in North Jakarta with a sea view, describes the ongoing battle against subsidence in her home.

We just have to keep fixing it. The maintenance men say the cracks are caused by the shifting of the ground.

She notes that when it rains, flood waters can submerge the swimming pool entirely, requiring furniture to be moved to higher floors. This pattern of incremental repair and temporary fixes represents a microcosm of the broader challenge facing Jakarta. The city addresses symptoms while the underlying cause continues to worsen, creating an endless cycle of damage and response.

The economic costs also include indirect effects that are harder to quantify but no less real. Health impacts from increased flooding, disruption to education when schools become inaccessible, and the psychological stress of living under constant threat all contribute to the human cost of subsidence. These factors affect quality of life and productivity in ways that economic metrics may only partially capture.

Concrete Barriers and Their Limitations

In response to the growing threat of flooding, authorities have turned to engineered solutions. Since 2014, the Jakarta administration and the central government have constructed around 20 kilometers of concrete barriers as part of the 46-kilometer National Capital Integrated Coastal Development project. These structures aim to protect the city from coastal flooding by creating physical barriers between the land and rising waters.

The approach has scaled up significantly with recent announcements. President Prabowo Subianto has unveiled a multibillion-dollar plan to build a giant seawall, a 500-kilometer megastructure along Java’s northern coast. This ambitious project would stretch from Banten to East Java, shielding flood-prone communities along the extensive coastline. The scale of this undertaking reflects the severity of the threat and the government’s recognition of the need for substantial intervention.

Another major project, the Great Garuda, involves building a 32-kilometer outer sea wall across Jakarta Bay along with 17 artificial islands. Supported by the Dutch and South Korean governments, this approximately $40 billion initiative would create an artificial lagoon where water levels could be lowered to allow the city’s rivers to drain properly. The design aims to address both coastal flooding and the challenges of managing river discharge during heavy rainfall.

While these structural measures have shown some effectiveness, experts warn they fail to address the primary driver of land subsidence. The existing seawall in Jakarta has helped limit seawater intrusion compared with unprotected coastal areas such as Demak in Central Java. However, as Mr. Yus Budiyono notes, such barriers do nothing to stop the ground from sinking. They may temporarily hold back the water, but they cannot prevent the land from descending to meet it.

Jan Jaap Brinkman, a hydrologist with the Dutch water research institute Deltares, argues that sea walls can only ever be an interim measure. He suggests that the Great Garuda project might buy Jakarta an extra 20 to 30 years to address the long-term subsidence problem. This extension of time is valuable but ultimately finite, and it does not change the fundamental equation that without stopping the sinking, any barrier will eventually be overwhelmed.

The construction of artificial islands has faced its own challenges. A plan to reclaim land by building 17 artificial islands off the coast of Jakarta included a design that would arrange them to form the shape of an eagle, intended as a national symbol. However, public opposition led to the cancellation of this plan in October 2017 by the newly elected governor of Jakarta at the time. Currently, only three of the 17 originally planned artificial islands remain under development or completed.

The social and environmental impacts of large-scale infrastructure projects also warrant consideration. Coastal communities that depend on fishing and other marine activities may see their livelihoods disrupted. Changes in water flow and sediment patterns can affect ecosystems. The massive concrete structures themselves alter the coastal environment in ways that may have unintended consequences. These factors complicate the assessment of purely engineered solutions to the subsidence challenge.

Nature-Based Solutions Gain Ground

Amid the focus on concrete barriers and massive infrastructure, alternative approaches based on natural systems have gained attention from researchers and urban planners. Nature-based Solutions, or NbS, offer a different paradigm for addressing Jakarta’s flooding and subsidence challenges. These approaches work with natural processes rather than against them, leveraging ecosystems to provide protection and resilience.

The concept of NbS in flood management involves various natural functions that can help mitigate water-related risks. These include rainwater interception through vegetation, increasing rainwater storage capacity, and restricting water flow to reduce erosion. In urban environments, NbS also provides additional benefits beyond flood control, such as filtering pollutants and reducing the urban heat island effect.

WRI Indonesia recommends a hybrid infrastructure approach that combines existing gray infrastructure with green infrastructure. This adaptive solution suits Jakarta because it can be applied beyond river areas to residential locations, helping to expand runoff control capacity and prevent local flooding. On the smallest scale, hybrid infrastructure takes forms such as biopore infiltration holes, green roofs, and rainwater collection tanks.

At a larger scale, NbS elements include multifunctional Green Open Spaces that serve as water catchment ponds, bioswales, and permeable pavement. Bioswales and permeable pavement also function as filters, preventing rainwater pollutants from entering drainage systems. Vegetation cover from green roofs and green spaces reduces air temperatures and energy use for air conditioning, providing climate benefits alongside flood mitigation.

The Jakarta government has begun to incorporate these approaches through Governor Instruction No. 52 of 2020, which outlines intervention plans including expanding green open space functions and developing vertical drainage or infiltration wells. Collaboration with related agencies aims to implement these nature-based strategies across the city.

Mangrove ecosystems represent another powerful natural defense against coastal flooding. These trees can calm waves and reduce surge-related flood damage by more than 15 percent annually. However, Jakarta’s mangrove cover has been severely depleted. Of the 291.17 hectares of mangroves that once existed, 272 hectares have been destroyed by infrastructure development and plastic waste. Only the Angke mangrove ecosystem in the western area of the capital remains.

Research from IOP Science emphasizes that handling floods and land subsidence requires an integrated watershed and groundwater basin approach. Simply draining water into the sea more quickly, which has been the primary strategy, may actually exacerbate land subsidence. Instead, increasing vegetation cover and constructing water conservation buildings in upstream areas can help address both problems simultaneously.

By increasing groundwater supplies through natural infiltration and conservation, cities can reduce land subsidence while also decreasing flooding risk. This approach also helps prevent seawater intrusion and drought during dry seasons. The restoration of degraded mangrove ecosystems and the creation of new green spaces represent tangible steps toward this integrated strategy.

The Water Management Challenge

At the heart of Jakarta’s subsidence problem lies a fundamental water management challenge. The city’s water demand far exceeds the capacity of its piped water system. Research indicates that water management authorities can currently meet only about 40 percent of Jakarta’s water demand. This substantial gap forces residents, businesses, and industries to turn to groundwater extraction as the only viable alternative for meeting their needs.

The population Jakarta serves includes approximately 9 million inhabitants within the city limits and another 15 million people who commute into the city for work each day. This massive concentration of people creates water demand that strains existing infrastructure. The failure to provide reliable piped water coverage across the metropolitan area creates a structural incentive for groundwater extraction that regulations alone cannot overcome.

Mr. Yus Budiyono emphasizes this connection, stating that access to clean water must be fully provided so there is no reason for groundwater extraction. He warns that without effective measures to curb land subsidence, even the proposed giant seawall would offer limited protection. The physical barriers may hold back the sea temporarily, but they cannot compensate for a city whose foundations are steadily sinking.

Improving water infrastructure management requires accurate, real-time information for monitoring and predicting water leakages, land subsidence, and groundwater levels. Cities can evaluate their water supply chains to identify alternative business models that meet local and industrial water demands without draining aquifers excessively. Solutions may include recycling wastewater, harvesting rainwater, developing desalination plants, and locating water services outside of impacted areas.

Artificially recharging aquifers by injecting them with surface water or treated wastewater could help restore groundwater levels. Tokyo successfully implemented this method when facing severe land subsidence fifty years ago. The Japanese government restricted groundwater extraction and required businesses to use reclaimed water, resulting in the halting of land subsidence. This example demonstrates that the problem is solvable, though it requires substantial investment and regulatory commitment.

The challenge for Jakarta involves finding alternative water sources that can replace groundwater extraction. Rivers such as the Citarum could potentially provide water, but they are currently extremely polluted. Heri Andreas estimates that it could take up to ten years to clean up the rivers, dams, and lakes sufficiently to allow water to be piped throughout the city or used as a replacement for deep aquifer extraction.

President Joko Widodo has acknowledged that cleaning up Jakarta’s rivers will take years of sustained effort. This long timeline creates pressure to find intermediate solutions that can reduce groundwater extraction while water infrastructure improvements proceed. Rainwater harvesting, improved efficiency in water use, and temporary restrictions on extraction in the most vulnerable areas may all play a role in bridging this gap.

The Political Dimension of Sinking

The story of Jakarta’s subsidence is not merely one of geology and engineering, but also of politics and social dynamics. Research published in Geoforum examines how land subsidence is intrinsic to the patterns of urban development that have characterized Jakarta since the New Order regime beginning in 1965. This analysis suggests that subsidence happens through interconnected moments of horizontal concentration, vertical extension, and differentiation in urban growth.

The research from 360info.org reveals a pattern connecting land subsidence, the increase in groundwater wells, and the expansion of the modern part of the city. All three factors increased distinctly since the 1960s, shaped by Indonesia’s political context under the authoritarian regime of President Suharto. During this period, Indonesia embraced capitalist-centralized development with Jakarta as its epicentre.

This analysis highlights a crucial aspect of the subsidence problem: those who cause it are not necessarily those who suffer most from it. Deep groundwater wells require significant investment to construct, meaning they are typically built by specific sectors that can afford them, such as hotels, malls, and high-class residential developments. These commercial operations cause substantial subsidence, while the impacts fall disproportionately on poorer coastal communities.

Dr. Bosman Batubara, a research fellow at the Asia Research Institute at the National University of Singapore, notes that Jakarta’s land subsidence is driven by rapid but uneven urban development. Communities that have benefited from decades of urban expansion tend to be less exposed to subsidence impacts. Meanwhile, coastal residents face disproportionately higher risks of flooding, land loss, and threats to their livelihoods.

The political response to subsidence has focused largely on surface-level solutions such as concrete seawalls rather than addressing root causes. Dr. Bosman argues that the government has yet to tackle the fundamental drivers of groundwater extraction and urban development patterns. Instead, resources flow into visible infrastructure projects that may appear to address the problem but leave its underlying causes untouched.

In 2021, Governor Anies Baswedan issued a regulation banning groundwater extraction in nine industrial areas and along 12 roads across the city. The current administration under Governor Pramono Anung reportedly plans to tighten these regulations further. However, enforcement remains a significant challenge. A 2017 inspection of 80 buildings in Central Jakarta’s Jalan Thamrin found that 56 had their own groundwater pump, and 33 were extracting water illegally.

Transparent governance of groundwater extraction represents one potential solution. Making information about the total number of deep wells, their depth, the volume of extracted water, and the builders or owners doing the extracting publicly available could improve management. This transparency, implemented alongside improvement of piped water services, could form part of a more centralized plan for Jakarta’s development.

Global Context and Lessons

Jakarta’s struggle with land subsidence places it within a global context of sinking cities facing similar challenges. Research from the World Economic Forum identifies New York, Venice, Mumbai, and others among the world’s sinking cities. The effects of urban land subsidence are being felt across coastal urban centers worldwide, driven by common factors such as groundwater use and excessive construction on certain soil types.

A recent study of 99 coastal cities found that 33 were sinking five times faster than sea level rise. This issue is particularly severe in parts of Asia, where cities like Manila in the Philippines, Karachi in Pakistan, and Tianjin in China are sinking 10 to 20 times faster than the rising sea level. Nearly half of China’s major cities are sinking under the weight of their infrastructure and due to groundwater extraction.

The human impacts of subsidence extend across these cities, resulting in significant land loss, water insecurity, infrastructure damage, and displacement of people. The scale of the challenge has prompted some governments to take drastic measures. Indonesia has decided to relocate its capital from Jakarta to the island of Borneo precisely because of these concerns. This massive undertaking represents an acknowledgment that some cities may become unsustainable in their current locations.

International experience offers lessons for addressing urban subsidence. The success of Tokyo in halting subsidence through artificial recharge and groundwater restrictions demonstrates that the problem is solvable. Other cities have implemented innovative approaches, such as public-private partnerships to fund infrastructure improvements, educational campaigns to reduce water consumption, and regulatory frameworks to manage groundwater extraction.

The World Economic Forum suggests five key actions for helping sinking cities: engaging communities directly, improving water infrastructure management, creating public-private partnerships, implementing industry best practices, and educating about water conservation. These comprehensive strategies recognize that subsidence requires multifaceted responses involving governments, the private sector, civil society, and academia.

Addressing urban land subsidence will require re-evaluating water use and infrastructure while making conscious efforts to build resilience into urban planning and design. The cities that succeed will be those that recognize the interconnected nature of the challenge and implement integrated solutions that address root causes rather than symptoms.

The Bottom Line

Jakarta’s subsidence crisis represents a complex challenge where geology, urban development, water management, and politics intersect. The city sinks while the seas rise, creating a dangerous convergence that threatens millions of residents and billions in infrastructure. Solutions exist, but they require addressing root causes rather than relying solely on visible infrastructure projects that may provide temporary relief without solving underlying problems.

• Jakarta’s land sinks at an average rate of 3.5 centimeters per year, with northern areas experiencing up to 25 centimeters annually
• Over the past 40 years, northern Jakarta has sunk by as much as 4 meters, leaving roughly 40 percent below sea level
• Without aggressive intervention, models predict 95 percent of North Jakarta could be submerged by 2050
• Excessive groundwater extraction causes most subsidence, with deep wells built by commercial operations having the greatest impact
• Jakarta loses at least US$186 million annually due to flood risks, projected to rise to US$421 million by 2030
• Infrastructure solutions include a 46-kilometer coastal barrier and a proposed 500-kilometer giant seawall along Java’s northern coast
• Experts warn seawalls only buy 20-30 years without addressing the root cause of groundwater extraction
• Nature-based solutions such as green roofs, bioswales, and mangrove restoration offer complementary approaches
• Water authorities can currently meet only 40 percent of Jakarta’s demand, forcing reliance on groundwater
• Tokyo successfully halted subsidence through artificial recharge and groundwater restrictions, offering a proven model