Jakarta, Indonesia, with a population already over 10 million, is one of the fastest-growing cities in the world. It's also one of the fastest-sinking cities. Every year, the ground subsides by as much as six inches in some neighborhoods. At that rate, as sea levels rise, northern Jakarta could be a few meters underwater by 2030.

In response, the city is embarking on one of the world's biggest infrastructure projects. Over the next three or four decades, the government plans to build a 21-mile long sea wall and 17 artificial islands to help protect the city from flooding. It will cost around $40 billion.

The project, like other new infrastructure for the quickly growing city, will be a challenge to pull off.

"Limited funding and a complex urban setting are two main challenges," says Victor Coenen, project manager for Witteveen+Bos, a Dutch firm that helped Jakarta create a master plan for the project. "The government is struggling to keep up with the pace of growth. Also, planning and construction of infrastructure is complicated in the densely populated metropolitan areas—relocation of residents is controversial, complex, and costly."

Even the technical details of the plan are an enormous challenge. Just supplying as much soil as the project needs will take more dredging vessels than are currently available in the entire world. Still, the master plan found that the project was feasible, and this month, the city took the first steps in construction.

The project is starting by temporarily bolstering Jakarta's existing sea wall. As parts of the city sink—a process driven by the fact that the city has been pumping out more and more groundwater for the growing population—and tides rise, the current wall isn't high enough.

In 2007, seawater crashed over the sea wall in northern Jakarta for the first time, adding to flooding from heavy rains that forced 500,000 from their homes. A year ago, the sea level came just inches from breaching the sea wall again, putting millions of people at risk.

The new seawall and artificial islands are designed to create a massive reservoir for the city, so surging water has somewhere to go before it reaches ground. The islands will also provide housing and office space for up to a million people. The project will also include other massive infrastructure upgrades, like new pipes for drinking water, so the city is no longer pumping from the ground.

Without the project, at least four million people would lose their homes. It's a challenge that isn't unique to Jakarta; cities like Mumbai, Shanghai, Ho Chi Minh City, Miami, Guangzhou, and many others are also struggling to figure out how to stay above water and keep drinking water safe. The question is which cities will be able to afford to save themselves, and which will be forced to relocate the people who live there.

"In the coming decades, no major abandonment is to be expected for those countries which can afford costly flood protection works," says Coenen. "For low-income countries, however, this is a realistic (and depressing) outlook for the longer term—several decades from now. I imagine that solutions will be developed, postponing the need for abandonment, but eventually some areas will become 'giant bathtubs', difficult and costly to protect."

NB: Press Cutting Service

This article is culled from daily press coverage from around the world. It is posted on the Urban Gateway by way of keeping all users informed about matters of interest. The opinion expressed in this article is that of the author and in no way reflects the opinion of UN-Habitat