The nearly 10 million people in the city and county of Los Angeles, California require a lot of water – most of which is imported snow melt from the Eastern Sierra Nevadas and Rocky Mountains, hundreds of miles away. UCLA researchers Stephanie Pincetl and Mark Gold are studying how Los Angeles can reduce its water imports and better capture, store and reuse water for a more sustainable water supply. "Sustainability: Water" is produced in partnership with the National Science Foundation.
Sustainability -- Water - Los Angeles & Water Imports
ANNE THOMPSON, reporting:
Los Angeles, California and its surrounding county is the second most populous region in the United States, with nearly ten million people. A population this large requires a lot of water-- most of it transported from hundreds of miles away.
STEPHANIE PINCETL (UCLA): We depend on imported water from the Colorado River, from the Easter Sierra and from Northern California that runs through The Bay Delta.
THOMPSON: L.A.'s water system was established in the early 1900’s as a way of bringing water from the snow-covered Eastern Sierra Nevada and Rocky Mountains to the city. This system capitalizes on an important part of the Earth's water cycle-- snowmelt runoff. When snows slowly melt, water moves down the mountains and eventually reaches rivers, in this case the Owens River. The Los Angeles Aqueduct then pumps some of this water, about 200 billion gallons a year, more than 400 miles to L.A. The management of this water is fragmented among multiple basins and water rights holders along the way, making it difficult for L.A. to fully utilize these water sources. Stephanie Pincetl, a researcher partly funded by the National Science Foundation, is director of the California Center for Sustainable Communities at UCLA.
PINCETL: A sustainable city needs to be able to understand or address water as a complete entity from supply and reuse and not simply separating them into different divisions or different labor and science. So the challenge going forward is how do we reconfigure how cities are run?
THOMPSON: Adding to the problem is a growing population in Southern California and a reduced snowpack in the mountains that supplies the water due to warming temperatures. A slowly melting snowpack releases water throughout the summer. But warmer winters bring more rain than snow, causing rivers to run much drier by late summer, creating the potential for water shortages.
PINCETL: It actually depends on how much rainfall and snowpack there is. So this year, we will probably be importing more water from the Colorado River, because the Sierra Nevada snowpack is going to be very light.
THOMPSON: To become more sustainable, several local and regional organizations, such as the Los Angeles Department of Water and Power, are devising methods to utilize something known as the urban water cycle, which seeks to capture, store and reuse the water that already exists in the city.
MARK GOLD (UCLA): The city of Los Angeles is trying to move towards a more urban water cycle where they're treating water all the same as one water, whether it's coming from rainwater, storm water, or waste water, or flood control, or recycled water.
THOMPSON: Local groundwater, or water that is below the ground surface and is recharged by rain and runoff, can provide an additional source of water.
GOLD: Right now in the city of Los Angeles, it's around ten to thirteen percent of local water supply.
THOMPSON: New innovative projects are looking at how runoff can be better controlled and filtered, rather than running directly to the sea. On Elmer Avenue in Sun Valley, water in the gutters is filtered through roadside bioswales, or landscape drainage systems. In the parking lot of the LA Zoo in Griffith Park, runoff is directed into the ground through pervious, or porous, pavement, to eventually filter through soils and into nearby streams.
IFTEKHAR AHMED (L.A. Department of Public Works): What they do is, they capture the storm water, hold it in the parking lot, it helps to infiltrate into the ground, recharge the ground water.
THOMPSON: L.A. is also improving how it reuses its water. At the West Basin Water Recycling Facility, pre-treated waste water is further purified to produce clean, useable water.
RON WILDERMUTH (West Basin Municipal Water District): It's water that has been cleaned enough to go to the ocean. And we take it and then we refine it and make it into ultra-pure water in many cases.
THOMPSON: Sustainability also means conserving water, even rain and storm water, something that L.A. residents are already good at.
People are putting in rain barrels, people are putting in rain gardens and so forth and people are really much, much more aware of the importance of treating water well as a precious resource.
THOMPSON: While the issues around the management of water continue in California, by building an urban water cycle that uses and reuses water sources more efficiently, Los Angeles hopes to pave the way to a more sustainable future.
LOS ANGELES — It’s a technology with the potential to ease California’s colossal thirst and insulate millions from the parched whims of Mother Nature, experts say.
But there’s just one problem — the “yuck factor.”
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