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The Dry Garden: More drought ahead?

August 20, 2010 |  8:00 am

Garcia-Garden-1

We’ve been getting mixed messages about whether or not we need to conserve water. On one hand, we had a decent local rain year. Last week, the state Legislature pulled a water bond from the November ballot that would have driven statewide conservation. This week, the Los Angeles City Council amended the two-day lawn sprinkler ordinance to a three-day version.

Crisis over?

Not by a long shot. Local rain doesn’t fill our pipes. Of the three main sources that do, Lake Mead, the Colorado River storage reservoir serving Southern California, shrank in July to its lowest level since 1956. Last month, the State Water Resources Control Board concluded that the Sacramento-San Joaquin Delta is overdrawn by 50%. Southern California could do its part to fix that by reducing water use from there by 30%, but more likely we will keep over-drafting the system until courts order stoppages because of the effects on fisheries.

As if things weren’t dicey enough, in early August the National Oceanic and Atmospheric Administration strengthened its La Nina advisory, a weather cycle that augurs drought for Southern California and two of its three main water sources, the Owens Valley and the Colorado River.

Timothy Barnett, a marine physicist from the Scripps Institution of Oceanography, wants planning to reflect comprehensive risk analysis. “We think it’s important to play ‘What if?,’ ” he said. In 2008, after looking at decreasing Colorado River flows and projected climate change effects, he and a colleague predicted that Lake Mead had a 50-50 chance of running dry in the next 20 years.

Last year, Barnett’s team revised that estimate, allowing that enough water would be kept in Mead to supply Las Vegas, but that scheduled deliveries could be missed from 60% to 90% of the time by mid-century. Who will miss them and how much will depend on how and if we revise the prevailing 19th century priority rights system.

As initially skeptical Western water managers have come around to believing that we are indeed in a dry cycle on the Colorado (they’ve had no choice; the reservoirs are half air), Southern California cities are shifting reliance to water imported from the Bay Area in Northern California. To ensure a constant supply from this source, our regional water wholesaler, the Metropolitan Water District of Southern California, is party to a lawsuit challenging pumping restrictions in place to protect historic salmon fisheries.

Garcia-Garden2 Should we have lawn at the expense of those fisheries? Whether we are aware of it or not, every time our sprinklers turn on, we are choosing lawn.

How worried should we be about the La Nina  prediction? According to Jet Propulsion Laboratory oceanographer Bill Patzert, “La Nina stacks the deck for a dry winter.” Since 1949, according to Patzert, 82% of La Nina years have had below-average rainfall. “You’re going out on a limb if you predict a multi-year drought, but this is a strong La Nina.” 

“The water situation in Southern California is serious,” Patzert added, “But I don’t think it’s dire yet. Six months or a year from now, we might not be using ‘serious.’ We might be using ‘dire.’ ”

The state Legislature passed the five bills behind the water bond in the belief that our situation is serious. Yet it pulled the bond from the November ballot last week because it wasn’t dire – at least not dire enough that lawmakers believed we would accept the $11-billion-plus price tag. The upshot: It’s left to us to split that hair about what we should do when watering our yards.

In leading the charge to expand the lawn watering days, Los Angeles City Councilman Greig Smith argued that because each cycle will be shorter, the new ordinance will save water. Time will tell if allowing irrigation on more days will result in using less water. It seems unlikely, particularly because during chamber debate, Smith made plain his belief that lawn watering should not be regulated.

Smith also argued that spreading out the watering days would spare city pipes pressure fluctuations that may have caused a rash of leaks last fall; however, Department of Water and Power engineers say main breaks are part of an old system and leaks were no worse during the two-day rule than they were when people watered whenever they wanted to.

Who’s right? And what should we do? Keep lawn? Get rid of lawn? Water more? Conserve? The most forward-thinking act is to landscape in a way that acknowledges the climate and does not take 40% of L.A.’s potable water and put it on lawn. When cutbacks come, the native or Mediterranean climate garden will cope with equanimity. Lawn will be dead.

For those interested in adapting their gardens to a drier, more socially responsible model, here is a list of events designed to help, sponsored by organizations dedicated to conservation of the West.

Sept. 3, 10, 17, 24: Four-part course. Replace your lawn, Tree of Life, San Juan Capistrano 

Sept. 4: Native plant clinic, Rancho Santa Ana Botanic Garden, Claremont 

Sept. 9: Firescaping with native plants, The Water Conservation Garden, Cuyamaca College, El Cajon

Sept. 11: Design fundamentals with Bob Perry, Theodore Payne Foundation, Sun Valley

Sept. 18, Oct. 2 and 23: Three-part series. Native plant garden design class, Theodore Payne Foundation, Sun Valley

Sept. 18, Native plant horticulture with Lili Singer, Theodore Payne Foundation, Sun Valley  

Sept. 23-26: Gardening under Mediterranean Skies, Pacific Horticulture Symposium, Los Angeles County Arboretum and Botanic Garden, Arcadia 

Sept. 25: Toss the turf, The Water Conservation Garden, Cuyamaca College, El Cajon

-- Emily Green

Green's column on low-water gardening appears here Friday mornings.

Photos: North Hollywood resident Gilda Garcia replaced her lawn with a mix of drought-tolerant plants. Credit: Anne Cusack / Los Angeles Times

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