The capital of Indonesia, Jakarta goes underwater

Problems

• The capital of Indonesia, Jakarta goes underwater

  The capital of Indonesia, Jakarta is one of the largest cities in the world. Its population is more than 10 million people. At present, the northern part of the city, where the administrative center is located, is going underwater, at a rather impressive rate of 27 centimeters per year. Of course, the situation is much earlier. In 2002, to protect the city from the water, the government built a wall along the coast. However, five years later, the wall was partially destroyed by a severe flood, which killed 80 people. Today, Jakarta residents live with the constant threat of another devastating flood. The government has even announced that the capital will be relocated to another city whose construction will begin this summer. But is there still a chance to save Jakarta or is the city doomed to sink underwater?

• Reasons why the city is going underwater

  Floods have been a major problem in Jakarta for hundreds of years. Yet the threat was not as serious as it is now. The city used to be protected by dense mangroves that acted as a barrier to the tides. Now the mangroves are virtually nonexistent. But that's not the only reason for the floods.
  Thirteen rivers flow through the city and into Jakarta Bay. From time to time they burst their banks. When the Dutch colonized Indonesia, they began to transform the city to resemble the Dutch. Along with the buildings, canals were built to divert water from the rivers. But according to experts, the canals only made things worse.
  The fact is that the alluvial loose soil of the river delta is compacted and constantly settles. New sediments from overflowing rivers can compensate for this settling. Canals, of course, prevented this.
  About 40 percent of the city is now below sea level. However, due to climate change and melting glaciers, the sea level rises every year. All this leads to regular flooding. The sea already reaches almost the top of the seawall. Water seeps through it, and as a result, the roads near the coast are always muddy and wet.

• Groundwater

  One of the causes of subsidence in Jakarta is also a large-scale groundwater abstraction. The fact is that the city has an undeveloped water supply network. The water system serves less than one million households, about a quarter of the city. The rest of the households pump water from the ground.
  As experts note, the number of deep wells has grown along with the city's population. One deep well can serve 50 households. Experts estimate that the city has already used 64 percent of its groundwater supply.
  In coastal areas, such as North Jakarta, where there is no running water, residents drill wells as deep as 150 meters. The alternative is to buy water in canisters, which are sold by distributors. A typical family of four earning less than $7 a day typically spends a fifth of that amount on water.

• Support for land subsidence countermeasures in Jakarta

  Making use of this experience in Tokyo, the Japan International Cooperation Agency (JICA) implemented a project from 2018 to 2022 supporting land subsidence countermeasures in Jakarta, the capital of the Republic of Indonesia. In Jakarta, excessive groundwater abstraction by factories and commercial facilities has led to subsidence, especially in the northern parts of the city, where land has sunk up to 4 meters since the 1970s. As a result, some areas are experiencing seawater inundation at high tide. It is estimated that if land subsidence progresses more, risks of flooding, storm surges, and logistical stagnation due to these natural disasters will increase over a large area.
  
  JICA introduced the concept of integrated water resources management to implement the project effectively. This concept refers to the systematic and comprehensive management of water use using fair methods and without damaging the sustainability of ecosystems in order to maximize the benefits gained from water.
  
  After the project ended, a Land Subsidence Planning and Implementation Committee (PIC) was set up as the successor to the JCC with the goal of implementing action plans. The action plans established by the JCC incorporate countermeasures such as constructing additional monitoring wells, expanding areas where well pumping is prohibited, constructing seawalls, and expanding land subsidence countermeasures for other cities.