Los Angeles Just Proved How Spongy a City Can Be

https://www.wired.com/story/los-angeles-just-proved-how-spongy-a-city-can-be/

By MATT SIMON, Wired. 

Excerpt: ...A long band of moisture in the sky, known as an atmospheric river, dumped 9 inches of rain on the city over three days—over half of what the city typically gets in a year. It’s the kind of extreme rainfall that’ll get ever more extreme as the planet warms. The city’s water managers, though, were ready and waiting. Like other urban areas around the world, in recent years LA has been transforming into a “sponge city,” replacing impermeable surfaces, like concrete, with permeable ones, like dirt and plants. It has also built out “spreading grounds,” where water accumulates and soaks into the earth. With traditional dams and all that newfangled spongy infrastructure, between February 4 and 7 the metropolis captured 8.6 billion gallons of stormwater, enough to provide water to 106,000 households for a year. ...Long reliant on snowmelt and river water piped in from afar, LA is on a quest to produce as much water as it can locally. ...Centuries of urban-planning dogma dictates using gutters, sewers, and other infrastructure to funnel rainwater out of a metropolis as quickly as possible to prevent flooding. Given the increasingly catastrophic urban flooding seen around the world, though, that clearly isn’t working anymore, so now planners are finding clever ways to capture stormwater, treating it as an asset instead of a liability....