March 2008

A Waterwise Future

San Diego County’s Water Conservation Garden has a serious mission: to educate county residents about the looming water crisis and to change cultural attitudes about landscaping.

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By Lyn Corum

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In 1994, Cuyamaca College joined the JPA and approved locating the garden on its property as part of its master plan. The college already had a strong horticulture department led by Brad Monroe, and he was one of the original drivers to create the garden. The college paid for a new design, when it shifted the location of the garden on the campus. This turned out to be a blessing, because the garden immediately grew from a planned 1.5 acres at the original location, to 4.2 acres at the new location adjacent to the college entrance.

Construction of the garden began in June 1998, and the grand opening was held in May 1999. Trubiolo managed the garden program and its operation until she retired in 2001.  The San Diego County Water Authority became a garden partner in 2001, and its administrative agency in 2003. The City of San Diego joined the Joint Powers Authority (JPA) in 2002, and Padre Dam Municipal Water District joined in July 2003.

Photo: Helix Water District
Plantings in cactus and succulent garden, featuring a South African pencil tree

Katherine Breece, the public affairs manager with the Helix Water District, says her district is looking at a large campaign to promote the garden.  “I see the garden as being the keystone of what I believe will be an aggressive outdoor water saver. We want San Diego [County] to have a San Diego landscape, and not look like Hawaii. San Diego doesn’t have an identifier, and we need to change the attitude about landscaping,” she says.

Breece says that at the peak of the drought in 1990, Helix ratepayers were using 177 gallons of water per day. Today, they’re using 131 gallons per day. Since people have changed their behavior, the necessary changes that will be needed in the future will be difficult.

Breece explained that one-third to two-thirds of the water a household uses is saved when the lawn is converted to a xeriscape landscape, depending on the replacement plants. This is easily done, she says, and the water conservation garden illustrates how to do it. A homeowner could put in a drought-tolerant front yard; roses could be moved to its own water-zoned area; and sage, rosemary, and blue hibiscus planted in another water-zoned area.

The garden has received international attention. The premier of Victoria State in Australia, which is experiencing extreme drought, came to see how the garden was promoting outdoor water conservation. Breece says she learned that many of the districts in Australia sold their facilities to private entities that make money selling water. The districts are now trying to buy them back so they can promote water conservation.

Irrigating Wisely
Schultz described the irrigation system operating in the garden. Six controllers operate remote valves. Each is set up to run about 24 valves, with the exception of one that operates eight valves. The valves will control either a sprinkler or a drip system. and the operation of each valve is determined by hydrozone characteristics. Each serves plants that have the same water requirements and sun exposure. Slopes will have separate valves for different rows, since water requirements of plants at the top will be different from those at the bottom of the slope.

An irrigation system always needs regular upgrading, Schultz says. Plants mature and change the elements surrounding them. A plant may grow to block the spray requiring that the sprinkler be moved. Drip irrigators will have to be added as a plant grows from its five-gallon container size. “I don’t think it is possible to design landscape irrigation that doesn’t need changing,” he says.

Dave Johnson, director of corporate marketing at Rain Bird, says watering the right amount of time is important feature of a waterwise garden. Too much water produces wasteful run-off. Just enough water means it is soaked into the root system and promotes deeper root growth. So, monitoring soil moisture to optimize irrigation running time becomes important.

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Johnson described some of the new technologies now on the market to help gardeners do that. Pressure compensator (or reducer) sprayheads will automatically respond to the amount of water pressure in the pipes. If pressure is high, it will be reduced at the sprayhead. When water comes out with too much pressure, it comes out as mist and gets blown away, producing wasted water.

The biggest development is the smart controller. It utilizes weather data and measures the temperature, rainfall, and solar radiation, and calculates how much water the plants should use. The controller can be located in a garage on the side of a building. Program in the date, the time, number of zones, and the controller will tell valves when to turn on. Larger installations like golf courses will have weather stations on site. Rain Bird has a controller called the ET manager. It is a wireless technology that communicates with local weather stations. Next Page >

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