A Watershed Moment in LA
Jan 07, 2010
2 Comments
Last week's rains reminded me of the fragility of our water supply in Southern California. While the rain is always welcome for its clearing of the air and the resulting soft green carpets that cover Los Angeles, I cannot help but wonder where all that precious water is going. Most of us are concerned over landslides, but if you live in the beach communities, you are often reminded after a rain, you cannot swim for several days because pollution levels in the water spike.
Before Los Angeles County became home to 10 million people, you had the untouched Los Angeles and San Gabriel watershed. Water from snow and rain ended up in the Los Angeles and San Gabriel Rivers, and eventually flowed into the Pacific Ocean. During the 20th century, both rivers were subjected to dams and concrete channeling, and runoff from areas paved with asphalt and cement completely changed the rivers' ecology (or technically, hydrology), resulting in many endangered and many lost species.
The rivers' alteration over time have also caused other problems:
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The high risk of flooding due to runoff having no where to go: concrete and asphalt do not exactly absorb water well.
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Polluted beaches and a filthy ocean: all that runoff is transporting household and industrial pollutants.
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Poor groundwater quality--what on earth is going into our underground aquifers?
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More pressure on LA's water supply: if we cannot capture water here, we need more from Northern California or outside the state--a resource no one wants schleped to the Southland.
Enter the Los Angeles and San Gabriel Rivers Watershed Council, or LASGRWC. This organization led the Watershed Augmentation Study, or WAS. Started 10 years ago as a partnership between local, state, and federal entities, The LASGRWC determines how LA can better capture storm water to reduce toxic runoff to the rivers and ocean while increasing local water supplies.
The WAS found no evidence of significant groundwater quality degradation from the infiltration of stormwater. The LASGRWC, City of Los Angeles, TreePeople, and partners are close to completing the Elmer Avenue Neighborhood Retrofit in Sun Valley, located in northeast San Fernando Valley. A bevy of solutions are underway here: the planting of drought-tolerant landscapes, installing more permeable surfaces, adding more greenspace and wildlife habitat areas, and storage facilities that will capture water for reuse or infiltration. The project also involves planting street-side stormwater gardens and driveway drains that will divert runoff from residential lots along Elmer Avenue. A large infiltration system under the site will capture and infiltrate runoff from the street that is not trapped by the landscapes above ground.
The project involves many partners, including Bureau of Reclamation, Department of Water Resources (Proposition 50), Metropolitan Water District, Water Replenishment District of Southern California, County of Los Angeles Department of Public Works, City of Los Angeles Department of Water and Power, City of Los Angeles Watershed Protection Division, City of Los Angeles Bureau of Street Services, Councilman Tony Cardenas, City of Santa Monica, Pomona College, TreePeople, and UC Riverside.
The Elmer Avenue Neighborhood Retrofit should be finished in February 2010 in time to infiltrate the remaining winter storms. If you have questions, you can contact Edward Belden, the water programs manager. To learn more about your "water footprint" and how you can have a role in reducing water pollution and waste, click here.
Great issues raised in this article! The latest thinking about stormwater management is that in addition to capturing, cleaning and detaining stormwater to keep it from overloading municipal stormwater systems and polluting the watershed, it can be retained for reuse. That is, we can hold that water and then harvest it when the weather is dry for irrigation and other uses. Retention and reuse make so much sense in an arid location like LA.
New underground storage systems (http://www.atlantis-america.com/index.html), are made from recycled materials and are 94% efficient in their use of underground space for storing large quantities of stormwater.
Thank you, John, for the comment. I had been wanting to write more about water reuse, and this organization is going a lot of great work! GGP