Turning Cities Into Sponges to Save Lives and Property

Imagine a sponge. Swipe it over a wet surface and it will draw up water; squeeze it and the water will trickle out. Now imagine a city made of sponges, or spongelike surfaces, able to soak up rainwater, overflowing rivers or ocean storm surges and release stored water during droughts. Engineers, architects, urban planners and officials around the world are seeking ways to retrofit or reconstruct cities to better deal with water — basically, to act more like sponges. While water management has always been an essential service in cities,…