Metropolitan Water District examines Descanso Gardens’ water use

Officials at Descanso Gardens gave Metropolitan Water District a look under the hood Friday morning, participating in a free irrigation survey designed to pinpoint spots where water efficiency upgrades could be made.

The audit is a service MWD offers at no cost to larger, nonresidential entities that maintain at least one acre of irrigation within the Metropolitan Water District’s 5,200-square-mile service area. Descanso has about 80 acres of cultivated, irrigated garden space.

During the three-hour audit, Gregg Roesnik, a San Diego-based certified landscape irrigation auditor contracted by MWD, examined various systems throughout the garden, reading meters and taking notes on his observations.

“We look for things like spray deflection, or runoff down the street,” Roesnik explained. “It’s a bunch of things that add up over time.”

Joining him on the tour were garden facilities manager Ken Godwin-Austen and Rachel Young, director of horticulture and garden operations, who explained the impetus for the survey.

“We know we have a very inefficient system in some areas of the garden we want to improve. We’re trying to figure out what the best first steps are.” Young said. “The survey will help us prioritize projects in the gardens.”

The team trekked through the Nature’s Table garden, where herbs and vegetables are watered by bubblers and a drip system, two of 27 different irrigation systems currently in operation.

As Roesnik made notes on a checklist, Young informed him that the sprinklers intended to water camellias often ended up spraying nearby oaks or even sidewalks. Together, the group checked systems as Young talked about Descanso’s desire to make upgrades.

“With the drought, we wanted to take the opportunity to work with programs that have become available and also to better communicate what we can do and what the public can do to conserve water,” Young said.

Currently, Descanso uses about 80 acre-feet of water, or about 26 million gallons annually, according to David Brown, the garden’s executive director. About half that comes from a source created by the property’s original owner, Manchester Boddy. The other half Descanso purchased from Valley Water Company, a MWD member agency, Brown said.

More than 90% of Descanso’s water is used by irrigation systems, some of which were installed in a piecemeal fashion in the early 1940s and comprise what Brown called “an underground patchwork of all kinds of pipes and valves.”

“Numerous improvements have been made through the years,” he added, “but, sadly, the only way you can know that an irrigation system isn’t functioning is when it breaks.”

Roesnik said he planned to have a list of results and recommendations within a week or two. He’ll also advise officials on what MWD rebates might be available to assist Descanso with any upgrades.

“We hope the survey will help us create benchmarks against which we can measure our progress,” Brown said.

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Follow Sara Cardine on Twitter: @SaraCardine.

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