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This Mixed-Use Treatment Plant Will Help Wean Los Angeles Off Colorado River Water

As the state continues to slog through a years-long drought, Los Angeles is attempting to free itself from the burden of imported water. All the water we need is right here in our sewer system, we just have to figure out how to make it usable. The Water Replenishment District of Southern California is on it: today they revealed plans for a $95-million water purification facility to be built in Pico Rivera as part of their Groundwater Reliability Improvement Project, reports KPCC. When finished, the facility should allow the water district—which covers the southern part of LA County starting roughly below the 10 Freeway—to be completely self-reliant and end the long practice of importing water from the Colorado River.

Today LA gets about 40 percent of its water from two underground aquifers, the Central and West Coast Groundwater Basins. It's the job of the Water Replenishment District to keep those overworked aquifers filled when LA sucks them dry. Ideally, melting snowpacks and rain runoff would be enough to fill them, but both are unreliable, especially during a drought. Captured rainwater accounts for less than half of the water needed to keep the aquifers filled each year, so the Replenishment District uses some manmade solutions to keep the aquifers full—they import water from the Colorado River and they pump in purified sewage water.

It takes a little more than 120,000 acre feet (1 acre foot is about 325,851 gallons) of water per year to replenish the aquifers. Rainfall covers 54,000 acre feet of that total, recycled water takes care of another 50,000 acre feet, and imported water accounts for the last 21,000 acre feet. That's 6.8 billion gallons of water being imported from the Colorado River each year to fully replenish aquifers. By 2018, when the purification facility is online, that number will drop to zero, replaced entirely by recycled water. This is crucial at a time when six other states are also importing water from the river.

Purification is cheaper too. Imported water costs about $1,000 an acre foot, whereas treated sewage water costs the district less than $200 for the same amount. That's an annual savings of $16.8 million when the switch to entirely recycled water is made.

Because mixed-use is LA's development mantra these days, the facility will also feature an outdoor amphitheater, large patio, educational exhibits on water recycling, and a connection to an existing bike path along the San Gabriel River.

· LA will soon use less imported H20, thanks to new water treatment [KPCC]
· Planned purification plant would eliminate need for imported water, officials say [LA Times]