Drip is Hip
1 Jul, 2008 By: Ken Krizner LivescapesThe popularity of drip irrigation grows in color and ornamentals uses.
The state of Colorado annually receives an average of 14 to 15 inches of natural precipitation, and most of that is in the form of snow in the spring. Such a small amount of precipitation forces landscape contractors to be as efficient as possible when it comes to irrigation.
The need for efficiency is why the overwhelming majority of irrigation projects in Colorado are drip irrigation.
"Colorado has some unique challenges," says Matt Edmundson, vice president of marketing and finance, and co-owner of Arbor Valley Nursery in Brighton, CO. "There is some form of drip irrigation in 95% of the irrigation jobs where there is any tree or shrub planting included."
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While drip irrigation's market acceptance began in areas where water conservation has been a major issue, such as Southern California and the Southwest U.S., more recently the market has grown, says James Podein, marketing manager of the Landscape Drip Division for Azusa, CA-based Rain Bird Corp. The Southeast, Northeast and Northwest regions of the country are currently showing the strongest growth in drip irrigation.
"In these regions, the knowledge and expertise with drip irrigation is behind but it is growing," Podein says. "Some contractors understand that drip irrigation is a growing trend and are becoming more knowledgeable."
He adds that drip is becoming an accepted form of irrigation in such applications as plant and flower beds, bushes and ground cover.
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Installation and Maintenance
Drip irrigation is a system where the water runs through pipes or tubes to a small device, called an emitter, which dispenses water onto the soil surface at a low rate. The water is almost immediately absorbed into the soil.
Because water sits 1 to 2 inches below the soil surface there isn't as much evaporation while it soaks in, compared with an overhead sprinkler system. In overhead systems, a percentage of that water vaporizes while it is airborne and additional droplets are blown away by the wind.
Once the water is in the soil, capillary action will move it sideways so it will wet an area usually about 24 to 36 inches in diameter around the emitter.
 THE SMALL tubes and emitters of a drip irrigation system can clog and break, but the extra maintenance of a drip system is offset by up to a 15% savings in water usage. |
Drip irrigation is a more targeted system, applying water in proximity to the plant's root zone.
While a good sprinkler system is about 75% to 85% efficient, a correctly installed drip system typically exceeds a 90% efficiency rate, meaning there is a 5% to 15% savings in water usage, says Jess Stryker of Ventura, CA, who has written a tutorial on drip irrigation (irrigationtutorial.com).
Like any irrigation system, landscape contractors can take a drip system, install it incorrectly and it will perform poorly.
"Some people think you can just throw it together and have a great system operating efficiently," says Ed Martin, associate director of programs and irrigation specialist at the University of Arizona. "If the emitter isn't just right, it could put out too much or too little water. The margin for error is much less."
In a drip irrigation system, tubing distributes water from the source to various parts of the landscape. The drippers are small emitters installed on the tubing, and they deliver water to each plant.
Tubing is laid out across the yard to connect a landscape. One length of tubing, known as a circuit, can serve many plants.
One common mistake in installing a drip irrigation system is placing emitters too close together, Stryker says. They should be kept at least 12 inches apart in sandy soil and between 18 and 24 inches apart in clay soil.
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