How sinking cities are rising

One of the main reasons is water – in many facets. First, the city is caught in a squeeze between rising sea levels and its own sinking land. Second, a deluge from 13 rivers, swollen by increasing urbanisation in their mountain sources, threatens to overwhelm the city's outdated water systems. Another of the facets is the rainwater. The urban drainage can’t keep up with the fierce rainstorms because they are choked by waste and sediment.

For these reasons and more, Jakarta has to contend with poor water quality and an inadequate groundwater supply, forcing residents to become self-sufficient. So, they pump out groundwater themselves, the ground falls away and the city continues to sink.

One significant issue with coastal cities like Jakarta is the presence of soft soils. The city is built on a mixture of alluvial soil and soft soil types such as clay, silt, and peat. These soils are highly compressible, which means that they are easily compressed under load. So, you can really imagine how the weight of buildings and houses causes the ground to sink the moment construction starts. 

The plan comprises numerous elements. Firstly, it aims to strengthen the existing infrastructure by reinforcing sea walls, enhancing pumping capacity, and improving drainage systems. However, these are merely short-term, urgent interventions.

Our strategy is twofold, blending immediate enhancements with visionary long-term reforms. However, in a decade of dedication, our ambition extends to a groundbreaking solution: constructing an offshore sea wall. This 25 km barrier would not only safeguard the city from the advancing sea but also mark a significant leap towards a sustainable future. While discussions continue, this bold vision could redefine Jakarta's fight against nature's forces, ensuring its resilience for generations to come.

Furthermore, there is consensus on the importance of halting groundwater extraction, as this would significantly decelerate the process of land subsidence.

The positive aspect is that some cities receive substantial financial support from governments for their protection. It is indeed feasible to safeguard cities to a significant extent. For instance, in the Netherlands, we have cities situated up to seven meters below sea level. Here, we are continuously elevating our dikes and embankments. Actually, there’s no technical limit to the protective measures that can be implemented.

I started my career with a background in geology, not exactly the go-to field for Water Management. However, life took an unexpected turn in 1995 during a major flood in the Netherlands. Working for the government at the time, I was drafted into a team tasked with handling the crisis. Initially, my role was to engage with the community and stakeholders, but I quickly found myself in the thick of problem-solving—expanding river spaces and raising riverbanks were my new daily tasks. This hands-on experience in the Netherlands, for over 15 years, was my real education in flood management. 

I'm particularly proud of several projects I worked on in the Netherlands. About 30 years ago, I played a role in an extensive flood management project. Our approach was innovative; we combined traditional river embankments with newer, more flexible solutions, effectively giving the river more space. This blend of strategies is something I take great pride in. It has been thoroughly tested and proven effective, significantly reducing the risk of flooding in the area. Additionally, I'm delighted with the construction of a robust sea wall in Jakarta, which has addressed the city's flooding issues hopefully for the next 10 to 15 years.

In the end, only one thing truly makes sense: I hope that governments improve at incorporating nature into their building plans and at planning wisely for the future, above all, in relation to groundwater.