Sprinkler device teaches grass to use less
By Kyra Epstein
U.S. Water News Online
ALBUQUERQUE, N.M. -- When some people retire, they play
golf and baby-sit the grandkids. Not Al Caprio. After retiring from
Hughes Aircraft, where he worked on the data processor for the
Galileo probe's landing on Jupiter, he opted for the more domestic
endeavor of conserving water by measuring relative humidity on Earth.
Caprio conceived of the Weathermiser, as he calls it, living
across the street from a large high school that always seemed to have
its sprinkler system on when it was raining. "My wife suggested I do
some research to create something that could forecast the weather and
wouldnÕt waste water when it was raining, and then keep it off after
it rains if the humidity was high," Caprio said. "I knew that if I
could come up with something that could sense evaporation and feed it
to irrigation timers, which are very inefficient, people could save a
lot of water."
By 1996, Caprio had convinced the 52-acre private school to use
his Weathermiser device, and by 1999 the school had reduced its water
consumption from 85 million gallons to 60 million gallons. Another
test site, the Albuquerque Hoffman Town Church, reduced its
consumption from 18 million gallons to 8 million gallons in the first
year of using the Weathermiser.
The device attaches to a sprinkler system's timer and shuts off
electricity to the timer when relative humidity -- or the amount of
moisture in the air at a certain temperature -- is higher than a
certain setpoint. Relative humidity is monitored and as the tension
on a small tape increases and decreases with the humidity in the air,
power is disconnected from timer. Caprio determined the setpoint by
studying 10 years of data on the highest average relative humidity
For example, for New Mexico over the last 10 years, the highest
average relative humidity was 60 percent. So for his clients in New
Mexico, Caprio sets his Weathermisers to turn off the sprinklers when
relative humidity is higher than 60 percent. "If it goes over that
point, chances are that it is raining, has just rained, or is about
to rain," Caprio said.
Caprio has installed between 1,000 and 2,000 units now and has
caught the attention of the City of Albuquerque and the State of New
Mexico, who have been helping Caprio test his invention. Dave Davis,
director of the Building Services Division for the State of New
Mexico, uses the Weathermiser to irrigate 50 acres of landscaping at
the executive office space for which he is responsible.
"When we first started using the Weathermiser, only half of our
building service complex was controlled by the Weathermiser," he
said. "We soon noticed that we were overwatering where the
Weathermiser was NOT used. We now have nearly all of the State
Building Services complexes adapted to the Weathermiser."
The Denver Water Board also contacted Caprio and asked him to
submit a proposal for a water conservation test program in Colorado.
In 1999, Denver Water bought 100 Weathermisers to use in test
locations in Denver and Pueblo. Caprio said that data results for the
single family home test sites are a 33 percent water savings.
Steve Brunner is vice president of engineering at Planetec Utility
Services in Golden, Colo., a company that is working with Denver
Water to help test the Weathermiser at five industrial, corporate,
and residential sites ranging from 1.7 acres to 30 acres.
Brunner said that the Weathermiser is not only helping to conserve
water, but is also helping the lawn to become healthier and greener.
"Most people water every day, but a little bit of stress is good for
a lawn in the long run," Brunner said. "If the roots can get down
deeper, to where the moisture is still in the soil, it's a healthier
Caprio said he has three versions of the Weathermiser. The least
expensive version costs $51.95 and is guaranteed for 5 years. Other
models have freeze sensors and/or wind sensors. And, Caprio said he
is developing another model, a system for golf courses that is remote
controlled. He hopes to start manufacturing the new model in 2001.
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