Elements 2010

From: Irrigation Technology's Growing Pains

Local Research, Done Smartly

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Programmable timers—tech newcomers a few years ago—offer efficiency. But just how much? To answer with science, the Municipal Water District of Orange County, CA (MWDOC), decided to test vendors’ claims under assorted conditions. The neighboring Metropolitan Water District of Southern California and the Irvine Ranch Water District joined MWDOC as partners.

MWDOC’s Scott Jakubowski and Joe Berg, who are the county’s water use efficiency  programs coordinator and manager, respectively, recount their efforts and describe what they learned.

Phase 1 launched a pilot look at just 27 homes in the neighborhood of West Park. The design concept was quite simple. Step one: Identify ripe large-volume users by looking at historic data. Second, permission was obtained from them to install smart timers.  Monthly water usage was then monitored. Finally, the before-and-after impact of timers was logged. “So,” Berg sums up, “its kind of a pre–water use to post–water use comparison.”

Result: On single-family homes, smart timers saved an average of about 37 gallons per day (gpd).

Phase 2: In 2004 came what MWDOC calls its “residential runoff reduction study,” which looked at runoff volume, properties, and impact on water quality (the latter being significantly impacted by irrigation).

Design ideas came this time from the National Water Research Institute (NWRI), which happens to be located in Orange County, and from the Southern California Coastal Water Research Project (SCCRWP).

What emerged was a five-neighborhood comparison study. Three of the five consisted of “control subjects, where we did absolutely nothing but monitor runoff volume, water quality, and use,” recalls Berg. A fourth neighborhood was given no smart timers, but residents got tutored on water efficiency. A fifth was equipped with smart devices.

Thought was also given to selecting neighborhoods with comparable terrain and demographics.

Result: Timers contributed to saving each resident an additional 42 gpd beyond education only; commercial landscape water use was reduced by 545 gpd. (For details and percentage figures, see www.mwdoc.com and navigate to the “water use efficiency” tab, listed under “research.”)

Validated test results helped MWDOC justify giving homeowners water tech rebates, for timers and for high-efficiency sprinkler nozzles that give uniform but reduced-volume distribution.

Orange County now boasts an estimated 4,800 smart timers, split evenly between home and commercial lawns.

Grants to pay for the studies were awarded from several sources, notes Jakubowski. Part of the success of a good study design is its ability to serve the needs of these constituencies, such as neighboring water districts, EPA, and state water resources control board.

“Consider what each agency needs, so you can include them,” advises Berg, looking not only at efficiency and flow monitoring, but runoff quality.

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“Piggyback all elements into one study, to get multiple funding opportunities,” adds Jakubowski.

Coming ahead: More pre- and post- comparative control studies, expanding into performance of system pressure regulators, sprinkler nozzles, and the impact of multiple measures. Results, as they come, will be posted at www.mwdoc.com.

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