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Is Los Angeles collecting enough stormwater?

The same flood-control system that protected L.A. from the atmospheric rivers also saw tens of billions of gallons of stormwater flush to the sea.

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L.A. County saw another near-record rain. How much of it will we get to keep?

Not enough.

When it comes to rain in Los Angeles, two conflicting priorities are at play: Get water out of the city as fast as possible and hold onto every last drop.

It’s something the Army Corps of Engineers, who channelized 51-miles of the L.A. River, wouldn’t have cared about following the devastating floods of ’38. But today, in the face of extreme weather changes, water resilience is top of mind for the Southland.

Last December, the L.A. County Board of Supervisors adopted its first ever water plan with the goal of sourcing 80% of our water locally by 2045.

That means reducing our reliance on imported water and investing instead in stormwater capture.

Enter the Safe Clean Water Program which passed in 2018 as Measure W. It will take an impermeable, concrete-lined city like L.A., and set up green spaces where stormwater can seep through the ground to replenish our county’s underground aquifers.

The program has a target of 300,000 acre-feet of captured stormwater by 2045, and there are concerns that it’s so far slow and piecemeal implementation. But if achieved, the program would accomplish nearly 50% of the county’s local water goals.

As of December, 126 stormwater infrastructure projects have been funded, but only a dozen have been completed.

But back to the question: How much of this storm did we keep? According to the Department of Public Works, we captured around 8,200 acre-feet. That’s about 3.6 billion gallons of water.

The first two days of the storm dropped nearly half of the region’s average seasonal rains, but the amount we collected was only a fraction of our average intake (65 billion gallons a year).

My colleague Hayley Smith reports that about 80% of the rain was lost to the sea.

Someone out there’s laughing at us… We’ll have to live with that laughter, and build a city that supports itself through the extremes of drought and torrents… of desire.

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