Conservation Matters July 2012

The Texas Land, Water and Wildlife Connection

Only a few "smart" irrigation controllers able to deal with 2011 drought

“Smart” Irrigation ControllersOnly a few "smart" irrigation controllers performed well during the 2011 drought, according to Texas AgriLife Extension Service experts.

"The controllers are still inconsistent," said Dr. Guy Fipps, AgriLife Extension irrigation engineer, College Station.

Fipps and Charles Swanson, an AgriLife Extension landscape irrigation specialist, tested nine commercial smart controllers during a 152-day period at College Station sites, from April through November during the 2011 drought.

The tests were the fifth year of evaluations of the controllers, which either download landscape water requirements from off-site service providers or use on-site sensors to calculate it themselves, Swanson explained. The data is then used to determine site-specific watering requirements and to operate the irrigation system automatically.

Ordinary "dumb" controllers rely on user-set timers to operate the irrigation system. When they are not set properly or run-times are not changed based on seasonal water needs, they are "notorious" for over-applying and thereby wasting water, Fipps said. Smart controllers often do better than dumb controllers, but from the tests, not all smart controllers performed the same.

During the 2011 drought, the College Station test site had less than 5.5 inches of rainfall in 2011 compared to 18 inches in 2010 and 14 inches in 2009. The 2011 drought was accompanied by unusually high temperatures and wind, so it was a good test of the controllers' performance during a drought, he said.

"No single controller was consistently able to provide the correct amount of water for all six zones tested during all seasons," Fipps said. "During the drought, evapotranspiration was 30 to 50 percent higher than average years. Some controllers did not adjust to the extreme conditions and applied inadequate amounts."

Read the full AgriLife TODAY article for more information.

Also, see "The art of smart irrigation" from the summer 2011 issue of txH2O for more on this research.

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