The Loma Prietan - July/August 2010

What You Can Do

Landscaping in a Land of Little Rain

by Catherine Elvert

Crystal Springs Reservoir is part of the Hetch Hetchy water supply, half of which is used for landscaping.
Crystal Springs Reservoir is part of the Hetch Hetchy water supply, half of which is used for landscaping.

The value of landscapes is indisputable. They help clean air and moderate temperature. They beautify and soften urban environments. They screen noise and unpleasant sights. They serve as refuges for people, birds, and other wildlife.

In California, landscape irrigation accounts for about half of all urban water use. The greatest potential for water conservation may lie just beyond our screen doors, but maintaining desired landscapes with limited water can be a delicate balance. It need not be a struggle; even in California a lush and vibrant landscape is compatible with minimizing supplemental irrigation.

Two main factors influence landscape water use: plant selection and irrigation efficiency. A landscape design with the right plants in the right place -- considering factors of microclimate, soil type, slope, and sun exposure -- can make a natural oasis that requires little maintenance or water. You need to select plants native to your locale and place them according to their tolerance for heat, cold, sun, and shade. Native plants generally require the least maintenance, and should not need much supplemental irrigation once established. (For more on this, see the "Gardening Green" column)

Although California's water resources are limited, high-water-using plants such as turf grass dominate our landscapes. Turf grass can provide a great playing surface for small children and pets, but if unused, it can translate into an unnecessary hole in your watering budget. One of the quickest ways to reduce irrigation is to replace such high-water landscapes with a combination of drought-tolerant and native plants and water-permeable hardscape, such as bark, pavers, or decomposed granite.

Irrigation Efficiency

An efficient irrigation system applies water only as necessary and to desired areas, rather than walkways, decks, or weeds. It applies water no faster and no more frequently than your soil can absorb it. Although sandy soils are porous and need more frequent watering, the Bay Area, particularly the South Bay, has a lot of clay soils on which water needs to be applied slowly and infrequently. On slopes, reduce runoff by using drip irrigation rather than overhead spraying.

Nonpotable water can provide another alternative for landscape irrigation. Recycled water is currently used extensively in nonresidential landscapes, and graywater and rainwater-harvesting (see Raindrops Keep Falling on his Roof on this page) systems are moving into residential backyards.

In most regions of California, homeowners and businesses can find incentive programs for water-efficient landscaping. The Santa Clara Valley Water District, for example, has developed landscape-irrigation audit programs, rebates for landscape renovation, irrigationhardware upgrades or repair, and educational resources. Contact your local agency to learn more about its water-efficiency program.

Catherine Elvert is a member of the Chapter's Executive Committee and a utility account representative for the City of Palo Alto Utilities. A version of this article appeared previously in the Sierra Club Bay Chapter's newsletter, The Yodeler.