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Using irrigation water more efficiently Paul Fattig photo Paul Kay checks a water meter at a test site for a new subsurface drip irrigation system in Ashland. It took a total nine inches of water last year to irrigate the 4,000-square-foot site at North Mountain Avenue and B Street; a similar site using sprinkler irrigation took 14 inches. Subsurface drip system drastically cuts evaporation By PAUL FATTIG ASHLAND - On the surface, the mulch is bone dry. But when irrigation consultant Paul Kay scrapes off the top layer with a shovel, he reveals a dark, moist subsurface. "This is ideal - just what we want," he said. The landscaped site covering some 4,000 square feet on the northwest corner of North Mountain Avenue and B Street is a demonstration plot for water conservation. With a dusty drought looming on the horizon, homeowners and others looking for ways to use water more efficiently may want to consider such a system, Kay said. Kay and the city of Ashland established the subsurface drip irrigation system at the site early last year. It took a total of nine inches of water to irrigate the site last year, compared to 14 inches for a landscaped area directly across the street on the east side of North Mountain. The latter was watered with a typical sprinkler system during that time. Both sites are about the same size and are landscaped with shrubs and young trees. "This system has a lot of potential," said Eric Setterberg, irrigation specialist for the city's Parks and Recreation Department. "We're certainly looking at it." The city has not yet compared the costs of installation and upkeep of the subsurface drip irrigation with traditional irrigating systems, he said. "It may be a little more labor-intensive than other systems," he said. "But there are some places where it could be applied very well. It might be very applicable to a lot of homeowners." Overwatering can cost homeowners in lost water and fertilizer, not to mention in energy bills to deliver the water, said Kay, a former landscaper who has a degree in business and economics from the University of California at Los Angeles. To install the system on 1,000 square feet of landscaping, the cost is about $1,300, compared to about $1,000 for an automatic sprinkler system in the same area, he estimated. "We can irrigate more efficiently with any irrigation system if we pay attention to ourselves, to changes in the weather and to what the plants actually need," he said. "But with subsurface drip irrigation, we can do that more precisely." The drip lines are either buried in the soil or under a thick layer of mulch. At the test plot, the drip lines were placed on top of the soil with about six inches of wood-chip mulch added. The mulch has compacted a bit over the past year. The system relies on capillary water movement instead of gravity to get the job done, Kay said. "It allows us to maximize the volume of soil that gets wet while minimizing the amount of wet surface," he said, noting that it drastically reduces evaporation loss. "We can actually trickle water into the soil a drop at a time," he added. "By releasing it slowly, you can make it go further." Releasing too much water at once with a traditional irrigation system causes it to run off or evaporate, he said. In addition to saving water, the subsurface drip irrigation system cuts down on the use of fertilizer, reduces erosion and helps control weeds, he said. The system is not perfect, he said, noting it must be faithfully maintained. That includes periodically flushing it to keep it from becoming plugged, he said. But few irrigation systems can match it for delivering water straight to the roots with relatively little water loss, he said. Using a computerized soil moisture detector, Kay determined that the dirt beneath the mulch contains about 33 percent water. "That means in this sandy loam it is getting full," he said. "The water is getting where it should." For more information on subsurface drip irrigation, contact Kay via e-mail at [email protected] . Reach reporter Paul Fattig at 776-4496 or e-mail him at [email protected] . Mail Tribune Home | Ottaway Newspapers, Inc. | Dow Jones & Co., Inc. | Privacy | Contact Us Copyright � 2001 Mail Tribune, Inc.