By DANIEL WEINTRAUB
May 29, 2008
In Australia, rainwater harvesting has been widespread for years, and in parts of the country it is the only source of fresh water. The government of Texas is an aggressive proponent of the idea. And in Washington's San Juan Islands, residents have overwhelmed a state agency that grants permits for the installation of harvesting systems.
But in California, the notion of capturing rainwater for use in irrigating landscape still has not reached the mainstream. Using rainwater for toilet flushing or even drinking is almost unheard of.
Dylan Coleman would like to change that. Coleman, from the town of Mount Shasta, is a consultant and seller of rainwater harvesting equipment. With his wife, he also runs a nonprofit foundation -- Save The Rain -- that raises money to pay for the installation of rainwater harvesting systems in Africa.
Lately, he has been much busier with the Africa project than he has been selling systems here under his company's Wonder Water brand.
"I've become more of an educational institution than an actual business," Coleman told me. "I do a lot of talks. Rainwater harvesting has skipped over a couple of generations. We've lost the knowledge. We are having to be reawakened to what it can do and how effective it can be."
Dan Carney, water conservation manager for the Marin Municipal Water District, says Californians have a sense of entitlement when it comes to water.
"We come from a history of feeling like there was an unlimited amount of water in the West," he says. "There was this idea that there was an unlimited amount of gold, of silver, of water, that it would never run out."
The gold and silver are mostly gone now, and while water is still abundant, attitudes about its use might soon be changing. The past two winters have been relatively dry, and this year's Sierra snow pack had only 67 percent of its average water content on May 1. With environmental laws and court orders diverting more fresh water to protect wildlife habitat, another dry year would likely leave the state in a water emergency. Already, cities from Roseville to Walnut Creek are under at least some form of water-use restrictions.
The growing interest in global warming might also contribute to pressures on water use. Water use - from pumping to distribution and treatment - consumes an estimated 20 percent of the electricity generated in California, and power plants are a major source of the greenhouse gases that are believed to be the cause of global warming.
Rainwater harvesting wouldn't be a panacea, but for many people, it might at least be the difference between having a green yard or a brown one, or provide enough water to wash their car when they want to. A more ambitious application of the technology could do a lot more.
The typical harvesting system is not very complicated. The best ones begin with a metal roof with a baked enamel finish, which stays fairly clean, but the method can be used with any roof style. Gutters collect the water, which usually flows through a fine screen to keep out debris and filter some contaminants. A diverter sends the first few gallons that come off the roof into a drainage system, and the rest is captured in cisterns, which can range in size from a few hundred gallons to several thousand.
That water can be used directly for irrigation. If the house has parallel water systems installed -- one for drinking, bathing and kitchen use, the other for laundry and the toilets -- rainwater can be easily used indoors, too. If it is filtered further or decontaminated with an ultraviolet light, it is safe to drink.
In Australia, the city of Melbourne is installing a 260,000-gallon underground tank to store water that will be used in a public park, and the city's design guidelines encourage the installation of water harvesting systems on all new construction.
In Texas, a state law directed the government to establish standards for the domestic use of harvested rainwater. A commission that studies the issue found that 2 billion gallons of water could be captured annually in Dallas -- and 38 billion gallons statewide -- if just 10 percent of the roof area were used for harvesting. The state recently established a "rain catcher award" to recognize the systems that best save water and money, and benefit the environment through innovative uses of the technology.
In Washington, the city of Seattle actively encourages harvesting. And on the San Juan Islands in Puget Sound, where many residents have little or no fresh water supply, interest in harvesting has surged, overwhelming a state agency that issues permits for the systems. In response, the agency granted "island-wide" approvals for the residents of Shaw and Lopez islands.
California has a reputation as a leader in environmental innovation. But when it comes to capturing the rain, the state seems to be behind the curve.
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