US Cities Could Be Capturing Billions of Gallons of Water Per Day

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US Cities Could Be Capturing Billions of Gallons of Water Per Day
With urban design upgrades, there’s no need to let so much rain go to waste.
By Matt Simon for Mother Jones

... Urban areas in the United States generate an estimated 59.5 million acre-feet of stormwater runoff per year on average—equal to 53 billion gallons each day—according to a new report from the Pacific Institute, a nonprofit research group specializing in water. Over the course of the year, that equates to 93 percent of total municipal and industrial water use. American urban areas couldn’t feasibly capture all of that bountiful runoff, but a combination of smarter stormwater infrastructure and “sponge city” techniques like green spaces would make urban areas far more sustainable on a warming planet.

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LA was able to capture 8.6 billion gallons of water from that atmospheric river in just three days, in part by diverting it into huge “spreading grounds” to percolate into the dirt. “In most of the country, we’re going to expect—and we’re already seeing—larger, more intense storms that deliver a lot of water in a short amount of time, and then longer periods between the storm events,” says Seth Brown, executive director of the National Municipal Stormwater Alliance, which provided input for the new report. “There has been this growing trend of: let’s live with water, let’s embrace water where it is, let’s manage it and value it as a resource.”

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Even in the Eastern US, which is more water-blessed than the West, cities like New York and Pittsburgh are scrambling to deploy green infrastructure to mitigate flooding. That could be a simple roadside area, like a rain garden or bioswale. More cities are also adopting stormwater fees, charging landowners based on the amount of impervious surfaces on a property, thus encouraging them to open up more ground. Where an impervious surface is required, like a sidewalk or parking lot, cities are using “permeable pavers” with gaps that allow water to get through. Recharging aquifers this way helps prevent the over-extraction of groundwater, which is causing the land itself to sink, known as subsidence.