Bad Science Hurts Smart Controllers

Brian VinchesiI have talked about smart irrigation controllers a number of times and how they, when properly installed and programmed, save large amounts of water. For review, smart controllers use sensor-based information, usually climatologically based such as evapotranspiration and rain sensors or soil moisture sensors to adjust the schedule of an irrigation controller. When programmed correctly, the controllers require little to no human intervention and water the landscape when needed, not on a set schedule of days, start times and minutes.

There have been many solid studies performed on smart controllers as they are a new technology and admittedly, some water purveyors and researchers have been skeptical of some of the manufacturer’s water savings claims.

The most notable study, “Evaluation of California Weather-Based ‘Smart’ Irrigation Controller Programs” is a long-term study being done throughout California by water authorities in the Los Angeles and San Francisco areas and represents more than 2,000 installed controllers. This study has released its preliminary results, but is slated to last five years. So far, results show a 6 percent or better water savings. Six percent may not sound like much, but when applied to the average landscape, it saved about 33,000 gallons of water, which dwarfs potential indoor water savings. Several other studies, including one in Frisco, Texas, demonstrate smart controller technology’s ability to save large amounts of outdoor water.

If you have been watching the press, the turf, landscape and irrigation industries are commonly being called to the carpet for using too much water and smart controllers are one way of proving the naysayer’s wrong.

Unfortunately, a recent study from Texas A&M University has received a great deal of press. The article, which appeared in a large number of online publications, was titled “Smart Controllers Not Very Smart.” The actual study is titled “Evaluation of Smart Irrigation Controllers: Initial Bench Testing Results (June 4, 2009).” The article states that all of the controllers used more water than the landscapes required. What the article did not say was the results were compared to what is recommended by Texas A&M. The test results were not compared to what was required by local weather data, which is what a smart controller is designed to provide to maintain the landscape.

The report states, “Additional testing is needed to verify these initial results.” The initial results appear to be based on one month of data, but admittedly it is hard to tell, and certainly a month is not enough time to reach any definitive conclusions.

Additionally it states, “The controllers could not be programmed with all the parameters required to define these virtual landscapes.” The study attempted to follow the Irrigation Association’s SWAT protocol, which uses six very diverse virtual landscapes, and compares the results to actual site-specific weather data and watering requirements. These issues are compounded by the fact that the manufacturers who donated the equipment were not consulted to see if the controllers were properly programmed. Many of the studies undertaken so far on smart controllers have shown that without proper programming and follow up to adjust the program, the controller will not save much – if any – water. These same studies show that when the follow-up adjustments are preformed the controllers reduce water use considerably.

This Texas A&M study reinforces the fact that the “set-it-and-forget-it” mentality used on most residential irrigation controllers wastes water. Applying that operational philosophy to a smart controller essentially renders it dumb. No surprise that the controllers were over watering. 

This study gives fantastic headlines, but was not peer reviewed. It is yet another example of poor science – or no science – that is used by to reduce the amount of water and/or turf available for future landscapes. If you are interested in factual smart controller studies and other studies of proven irrigation technologies that save water, check out www.swatirrigation.org and irrigation.ifas.ufl.edu. Unfortunately, these studies don’t seem to garner press attention.

As an industry and as an individual, if you want to stay in business designing, installing and maintaining beautiful landscapes and the irrigation systems that support them, it is important to take a stand against bad science. It is a detriment to the green industry and with increasing frequency it is being used to attack turf and irrigation. You need to point it out to your customers and others that you and the industry are environmentally responsible and back up the products and claims that you make. If you don’t, who will?