Rainwater Harvesting Emerges From Closet



There was a time in the Rim country when rainwater harvesting was something you didn't talk about in polite company.

Rumor had it that Salt River Project, which owns the surface water rights to a 13,000-square mile watershed that includes the Rim country and the entire Tonto National Forest, frowned on the practice of capturing, diverting and storing rainwater for landscape irrigation and other uses.

"I think there were some misunderstandings about the legal implications of it, because there are certain activities you can't do -- like you can't dam up water," Karen Probert, town water quality specialist, said.

Whatever the reasons, nobody is frowning on rainwater harvesting anymore, especially in these times of severe drought. Salt River Project officials even endorse the practice as good for everybody, including themselves.

"I've talked to a representative of SRP, and they said they actually would encourage people to do that, and that there's no legal problem as long as it's on their own property," Probert said.

While rainwater harvesting is just starting to take off in the U.S., Jim Ryan, a Scottsdale resident who is a leading proponent and authority on the subject, said its use goes back centuries:

"Rainwater harvesting is actually an ancient practice, used in India and the Middle East more than 2,000 years ago, then later by the Romans, and more recently by 19th century settlers as they cultivated the Midwest," he said.


A concrete rainwater harvesting cistern, at left, is incorporated into the deck behind this house.

Many other countries are far ahead of the U.S. in their utilization of rainwater harvesting, according to Ryan.

"For instance, in Germany there are more than 400,000 systems installed; across the Caribbean 500,000 people depend upon rainwater harvesting systems; and in Australia more than 82 percent of people in rural areas rely on rainwater harvesting systems for all their domestic water supplies," he said.

Within the U.S., Ryan said, more and more people are installing systems, ranging from locations as diverse as Washington and Montana in the Northwest, and from Los Angeles to Texas, Florida and the U.S. Virgin Islands, where, in fact, rainwater harvesting is required by law on all new construction. There are several reasons rainwater harvesting is enjoying a resurgence, according to Ryan:

  • Rainwater is one of the purest sources of water -- distilled by nature.
  • Rainwater is naturally softened, clear, and odorless.
  • Because it does not contain dissolved minerals as does groundwater, it is ideal for bathing, washing hair, and drinking.
  • At a time when water rates are rising, rainwater is free.

"Sometimes it is a matter of water scarcity, sometimes it is due to poor water quality or even contamination, and sometimes it is just a striving for a sustainable and self-sufficient source of pure water," Ryan said. "But one thing is certain: as populations grow and our demands for water continue to increase, the growing pressures upon our water resources will make scarcity, purity, and price more and more important issues for homeowners ..."

In its simplest form, rainwater harvesting means collecting rainwater from a roof and storing it in receptacles of varying types and sizes, from simple barrels to giant storage tanks.

It's amazing how much water can be collected off a roof. From a heavy rainfall of one inch, a normal sized home (1,600 square feet) can easily accumulate 1,000 gallons of water, according to Ryan.

A number of storage systems are available, and if you have a metal roof, the water can be of drinking quality. In fact the advantages of metal roofs are numerous:

  • They are impervious, meaning that all the rain easily runs off without being absorbed.
  • They generally have smooth surfaces, which the initial rainfall will easily clean of dust, bird droppings, and other potential contaminants (some systems use a "first flush" water diverter to automatically exclude this "roof cleaning water" from going into a tank for storage).
  • In dry or sunny regions the heat of the metal roof helps warm the initial rainwater to better clean the roof and gutters before water is diverted to storage.
  • In areas prone to brush or forest fires, the combination of a metal roof and a cistern full of water can be easily used to protect homes at risk by reversing the flow, thereby pumping water from storage to the downspouts until the gutters overflow, surrounding the home with a veil of water.
  • Metal roofs are tough. In areas where flooding or hurricanes are a threat, rainwater harvesting systems can continue to provide sustainable pure water even when traditional sources of water are knocked out or contaminated.

While the cost of a rainwater collection system varies widely, an average price is about $6,000, exclusive of roof and gutters, according to Ryan. But if you don't want to spend that kind of money, there are other things homeowners can do to salvage the water that falls on their properties.

"Some people don't like the looks of the receptacles or don't have space for them," Probert said. "That's OK, because you can do things out in the yard that can accomplish the same purpose."

Probert is currently creating a brochure that tells you how to harvest rainwater through such techniques as berms and rock-lined basins that slow the flow of water on your property and get it into the ground.

She recently traveled to Tucson to check out a home with a beautifully landscaped yard where groundwater harvesting techniques have proven extremely effective.

"They have a small lot, 70-by-100 feet, which you wouldn't think would have much potential for rainwater harvesting," she said. "But just by using simple techniques and putting some different structures in their yard -- and it's a beautiful yard, they're able to capture 1.5 inches of rainfall, which equates to about 6,000 gallons, before any water runs off their property. That's a huge quantity of water."

People who want to see some of the rainwater harvesting techniques for themselves can visit the xeriscape demonstration garden in the courtyard of Gila Community College at Highway 260 and Mudsprings Road.

"It isn't evident at first that we've incorporated rainwater harvesting throughout that whole garden, but take a closer look and you'll see a number of basins and swales and berms that were designed to direct water from the downspouts off the metal roof through as much of that garden as possible, so it can percolate in and water those native plants that are demonstrated there. We also have a barrel there to catch rainwater," Probert said.

Rainwater harvesting is especially critical while the Rim country is suffering through a drought.

"Some climate studies going on right now indicate this drought is prolonged and severe," Probert said. "We may get some relief from these periodic rain events, and that's another reason rainwater harvesting is so important, because if people are prepared they can collect it and make the best use of it."

Probert hopes the town's new rainwater harvesting brochure will be available soon. In the meantime the town water department stocks a free publication that was produced by the city of Albuquerque on the subject: "Rainwater Harvesting: Supply from the Sky."

Probert says Rim country residents can also call her at (928) 474-5242, ext. 235 with any questions.

Ryan can be reached via e-mail at rwh@cox.net.

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