Jakarta, capital of Indonesia, is huge: it has a population of at least 10 million, and is one of the fastest growing cities in the world. Unfortunately, it’s also sinking, with sea levels rising by as much as 6 inches a year and 4 million homes currently under threat.

And so the government’s announced the giant infrastructure plan it hopes will solve the problem. It involves a giant, 35km long sea wall and 17 artificial islands, and it will come at the low, low price of $40bn. Here’s a jazzy rendering:

The islands, as you’ll obviously be able to tell, are in the shape of the Garuda bird, Indonesia’s national symbol:

This modest plan is easier described than implemented.  According to Fast Company magazine, just supplying the amount of soil needed will take more dredging vessels than presently exist in the entire world. The government also needs to gather together that $40bn. Meanwhile, the city’s population is still rapidly expanding.

Despite these worries, the city’s gone ahead with phase one, which involves raising the current sea wall. This, along with the planned man-made islands and building a new sea wall further out into the bay, is intended to act as a reservoir, blocking waves from breaking on the city’s northern coastal areas and storing water during the rainy season.

The plan also aims to tackle another source of the sinkage. The city has been taking its water supply from groundwater, which has left the ground beneath the city sponge-like and full of holes. As Victor Coenen, one of the consultants who devised the plan, told Japan Times: “Basically, we are pumping ourselves into the ground.” To tackle this, the city now plans to pipe in drinking water from other sources.

The new sea wall is due to be completed between 2025 and 2030; the islands about 10 years later. But the city doesn’t have the best record with large-scale infrastructure projects: construction on a monorail system started in 2004, stopped in 2008 and is now just about moving ahead again. Let’s just hope the imminent threat of sinking into the sea is enough to ensure that the bird-shaped islands become a reality.