Part 4: Can groundwater quench our thirst?

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And houses have been fitted with storm drain water capture for watering lawns and other use. (Photo: Matt Holzman)

Listen below as Madeleine Brand and Saul Gonzalez report on the Los Angeles Aqueduct.

The San Fernando Valley is a giant aquifer, basically sitting on a sponge that can absorb a lot of water, and because it’s underground, that water doesn’t evaporate. However, due to paving the aquifer doesn’t absorb as much water as it could. About 85 percent of the city is paved, which prevents water from getting to the natural storage tank. Remember the L.A. river is paved too, so we’re basically sending any water that could be conserved straight into the ocean.

But some hope that will change. Co-founder of the Arid Lands Institute at Woodbury University in Burbank, Hadley Arnold, is exploring new ways to conserve water, including making the aquifer useful again.

On a residential block in the valley, Arnold has championed a demonstration project created by a group of city agencies and nonprofits. This block had a severe flooding problem – so the goal of the project is to care of the excess water and create a model for the future.

The houses look pretty much the same as on the other block, but the asphalt driveways have been dug up and replaced with gravel or loosely placed paver stones that allow water to sink into the spaces in between. Even the street is porous.

The hope is that some day all of this saved-up water can be used for drinking. But that’s not a given. Much of the underground water is contaminated. From the 1940s until the 1980s, the Valley was a manufacturing center, home to heavy industries like aerospace. And they dumped their poisonous chemicals down the drain and into the aquifer. Now the city wants to spend 800 million dollars to build water treatment plants, which could mean water for 500 thousand people a year.

Madeleine Brand talks to Hadley Arnold on San Fernando Valley street (Photo: Matt Holzman)
Madeleine Brand talks to Hadley Arnold on San Fernando Valley street (Photo: Matt Holzman)
It looks like a regular old street in the SFV but look closely...the streets absorb water so it seeps down in to the aquifer below. (Photo: Matt Holzman)
It looks like a regular old street in the SFV but look closely…the streets absorb water so it seeps down into the aquifer below. (Photo: Matt Holzman)
What does roll off into the drains is also directed down to the aquifer rather than out to sea. (Photo: Matt Holzman)
What does roll off into the drains is also directed down to the aquifer rather than out to sea, so that one day it can be used for drinking water.  (Photo: Matt Holzman)
Swales are dug out front to catch water. (Photo: Matt Holzman)
If it isn’t absorbed in the garden or driveway, the water flows into swales, basically ditches, built between the sidewalk and street. Swales are dug out front to catch water. (Photo: Matt Holzman)

On the 100th anniversary of the Los Angeles Aqueduct, we look at William Mulholland’s legacy and the on-going quest to quench LA’s thirst. More at: Power & Water: The Los Angeles Aqueduct at 100  This series was reported by Madeleine Brand and Saul Gonzalez and produced by Matt Holzman.