Earlier this month, the longer term fell on Los Angeles. A protracted band of moisture within the sky, referred to as an atmospheric river, dumped 9 inches of rain on the city over three days—over half of what the town sometimes will get in a yr. It’s the type of excessive rainfall that’ll get ever extra excessive because the planet warms.

The metropolis’s water managers, although, have been prepared and ready. Like different city areas all over the world, lately LA has been remodeling right into a “sponge city,” changing impermeable surfaces, like concrete, with permeable ones, like grime and vegetation. It has additionally constructed out “spreading grounds,” the place water accumulates and soaks into the earth.

With conventional dams and all that newfangled spongy infrastructure, between February 4 and seven the metropolis captured 8.6 billion gallons of stormwater, sufficient to supply water to 106,000 households for a yr. For the wet season in complete, LA has collected 14.7 billion gallons.

Long reliant on snowmelt and river water piped in from afar, LA is on a quest to provide as a lot water as it could regionally. “There’s going to be a lot more rain and a lot less snow, which is going to alter the way we capture snowmelt and the aqueduct water,” says Art Castro, supervisor of watershed administration on the Los Angeles Department of Water and Power. “Dams and spreading grounds are the workhorses of local stormwater capture for either flood protection or water supply.”

Centuries of urban-planning dogma dictates utilizing gutters, sewers, and different infrastructure to funnel rainwater out of a metropolis as shortly as potential to forestall flooding. Given the more and more catastrophic urban flooding seen all over the world, although, that clearly isn’t working anymore, so now planners are finding clever ways to seize stormwater, treating it as an asset as a substitute of a legal responsibility. “The problem of urban hydrology is caused by a thousand small cuts,” says Michael Kiparsky, director of the Wheeler Water Institute at UC Berkeley. “No one driveway or roof in and of itself causes massive alteration of the hydrologic cycle. But combine millions of them in one area and it does. Maybe we can solve that problem with a thousand Band-Aids.”

Or on this case, sponges. The trick to creating a metropolis extra absorbent is so as to add extra gardens and different inexperienced areas that permit water to percolate into underlying aquifers—porous subterranean supplies that may maintain water—which a metropolis can then draw from in instances of want. Engineers are additionally greening up medians and roadside areas to take in the water that’d usually rush off streets, into sewers, and finally out to sea.

As the American West and different areas dry out, they’re looking for methods to provide extra water themselves, as a substitute of importing it by aqueduct. (That technique consists of, by the best way, recycling toilet water into drinking water so cities scale back water utilization within the first place.) At the identical time, climate change is supercharging rainstorms, counterintuitively sufficient: For each 1 diploma Celsius of warming, the environment can maintain 6 to 7 % extra water, that means there’s usually extra moisture out there for a storm to dump as rain. Indeed, research have discovered that the West Coast’s atmospheric rivers, just like the one which simply hit LA, are getting wetter.