Performance of Weather-Based Residential Irrigation Controllers in a Desert Environment

Weather-based irrigation controllers have the potential to conserve water.  The objective of this research was to test the performance of five weather-based irrigation controllers and one user-controlled irrigation controller.  The Rain Bird ET manager, Hunter ET system, Irritrol Smart Dial, Aqua Conserve (ET-6), Weathermatic (Smart Line), and the user-controlled Hunter Pro C controller were tested.  The Hunter Pro C was manually programmed to irrigate at 80% of historical reference evapotranspiration.  Controllers were connected to a sprinkler system that irrigated 3.6 by 3.6 m tall fescue (Festuca arundinacea) plots.  The irrigation system was equipped with low flow electronic sensors connected to a datalogger.  Controllers were field-tested in Las Cruces, New Mexico from the Dec. 15, 2009 to Jan. 31, 2010.  During the experiment, there were six rainfall events that averaged 6.3 mm/event.  The Irritrol Smart Dial applied 45 liters of water per square meter of turf and had an irrigation event every 16 days.  Rain Bird ET manager applied 63 liters/m² had an irrigation event every eight days.  Weathermatic (Smart Line) applied 92 liters/m² and had an irrigation event every seven days.  The Hunter Pro C, Hunter ET system, and Aqua Conserve applied 95, 179, 248 liters/m², respectively.  While the Hunter Pro C had one irrigation event every seven days, the Hunter ET system irrigated every four days.  The Aqua Conserve had an irrigation event almost daily.  Although our preliminary results show that the Irritrol Smart Dial and Rain Bird ET manager applied the least water when compared to the user-set hunter controller, longer testing will be needed to gauge how well those controllers maintain turf quality.