Rising sea levels are a growing worry for many coastal cities around the world. While all are expected to be impacted, some like Indonesia's capital Jakarta, are more vulnerable. Located in the northwest coast of the Java Sea, Southeast Asia's most populous city lies on a low flat basin at the mouth of the Ciliwung River on the Jakarta Bay. Though its average elevation is 8-meters (26 feet), 40% of the city lies below sea level and is sinking by as much as six inches, annually. Experts speculate that if this pace continues, much of northern Jakarta will be underwater by 2030.
The problem is exacerbated by the proliferation of boreholes that are being constructed to extract drinking water from underground. This has caused the soft clay delta soil to compact in certain areas of the city and help accelerate its sinking. If that is not bad enough, the flooding triggered by the overflowing Ciliwung and the smaller Pesanggrahan and Sunter rivers during the monsoon season, forces tens of thousands of shanty dwellers out of their homes annually.
While these issues have been known for some time, a 2007 flood that breached the city's existing sea wall for the first time brought about a new sense of urgency. After many years of planning and deliberation, in October 2014, Indonesian officials announced a multi-billion dollar project that they believe will save the city from disappearing.
The first priority will be to strengthen the existing sea wall around the northern part of the city. However, since it was constructed to withstand much lower water levels, this will provide the area's four million inhabitants only a temporary respite against the rising seas. The permanent solution is a more ambitious, multi-decade project, that entails building a 21-mile long wall and 17 artificial islands that are designed to shield the city from the rising sea levels. In addition to protecting Jakarta, the islands will also have housing and office space for up to a million people, a big help for the overcrowded city of nine million residents.
Also included in the plans is a massive reservoir that will be situated between the islands and the sea wall to absorb the runoff water from the rivers during the monsoon season and put an end to the annual flooding. Massive infrastructure upgrades like new pipes for drinking water, will alleviate the need for boreholes and prevent the ground from collapsing further.
Though the plan sounds perfect on paper, there are many hurdles that need to be overcome before it becomes a reality. The biggest issue of course is whether the country can afford the cost, which is expected to be about $40 billion USD over 20 years. Then there is the logistical challenge of building infrastructure in a densely populated city like Jakarta, given that relocation of residents could be extremely expensive and also, controversial. Even if these issues can be solved, there is still the technical challenge of gathering the large amount of soil that will be required to build the islands. Experts believe that it may be a hard feat to pull off even if the project engineers can get access to all the dredging vessels in the world.
Whether the giant wall and the islands, that will form the shape of a Garuda – the mythical bird that is Indonesia’s national symbol - will ever be built, remains to be seen. But the fact that the government has even come up with a plan is commendable, given that officials in other vulnerable cities like Bangkok, Dhaka and Mumbai, have not even begun to address the issue.