Contacts
 






Keyword Site Search










Cities Embrace Drip Irrigation for Commercial Projects

By Gregory V. Harris, regional editor








The CDIS grid system has been placed on a large slope at the Redhawk housing development in Temecula, Calif. The system is comprised of a uniformed pattern on a 6-foot by 6-foot grid that applies water to 100 percent of the area with one emitter every 36 square feet.


Despite being renown as a water conservation tool, drip irrigation systems have not proven to be a popular choice as a water delivery tool for many municipalities around the country.

The success of the drip system relies heavily on its design and its ease of maintenance. Low-volume irrigation systems are similar in their basic layout to any other irrigation system. They consist of a main supply, a control zone, and a lateral/water delivery system.

The main supply consists of the pipe network from the point of connection to the control zone. Depending on the requirements of the local municipality, it may also include a water meter, backflow preventer, and isolation valves. Basic hydraulic principles apply to the size and installation of the pipe network.

Larry Gross, general manager of Riverside, Calif.–based Sunshine Nursery, said many communities have used drip designs that have been hard to maintain and keep running correctly. Drippers have become clogged, spaghetti tubing gets damaged while maintaining the grounds, and these systems have a large number of little screens that must regularly be cleaned. In addition, these systems have failed quickly.






On large slopes, CDIS is laid out in 6-foot by 6-foot grids by a crew of five to six installers. More than 25,000 square feet of land can be watered using the 6-foot by 6-foot grid. The grid includes two drippers and a one-inch valve. Approximately 21 gallons of water per minute can be delivered to the site via the grid.


Gross, who has developed an irrigation tool that he refers to as Commercial Drip Irrigation Systems (CDIS), said a community’s bad experience with drip irrigation in the past can be a negative when approached about implementing a new drip irrigation system for their water delivery needs.

“Counties and/or cities that have had no success with drip irrigation usually say ‘Thanks, but no thanks’ when I present the CDIS,” Gross said. “It’s difficult to convince them to change their minds.”

Gross said that many civic leaders that he has been in contact with do not understand drip systems, which contributes to the lack of enthusiasm about this water delivery method.

“We need to educate city and county agencies, architects, installing contractors and city and county agencies to understand how the drip irrigation system could work and benefit their agencies,” he said. “That would solve any and all qualms over previous concerns from the past.”

Drip irrigation is considered one of the most efficient, cost-effective ways of delivering water to plantings. The practice of applying water at very low volume over a longer period of time helps to put the water deeper into the root zone of the plants. In addition, water loss from wind drift and evaporation is minimized.

Gross has designed and developed his CDIS for the Southern California cities of Temecula and Murrieta, where roughly 10 million square feet of drip irrigation is under his design.

“A number of these areas have been maintaining approximately four years,” he said. “The system is more flexible than others with less chance of breakage.”






The project at Redhawk features 24 stations and about 24,000 square feet of grids. It took crews about one week to place the grids.


The CDIS is designed to water plants and trees using a measured amount of water per plant and/or tree under low pressure. According to Gross, there are six goals for CDIS: no water runoff, less weed growth, less water used than overhead irrigation systems, far less evaporation, less vandalism and less erosion.

“With the CDIS, no water runoff will occur even if there are V-ditches, which leads to less weed growth,” Gross said. “The water is strictly zoned to only wet the area around the intended plant and/or tree.”

Gross added that CDIS uses less water than overhead irrigation systems. An added bonus of CDIS is a reduction in vandalism. Once ground cover is placed, the CDIS is hidden from view.

“The only vandalism that I see occurs when we are installing the system,” Gross said. “Usually a couple of drippers are stolen, but these are very inexpensive at maybe one dollar per dripper. If 11 drippers are stolen, for example, it will only cost $11 to replace them, which is much better than paying $600 to replace a stolen pop-up.”

Vandalism issues notwithstanding, Gross said one of the most frequent questions he receives about CDIS due to being made nearly invisible by the ground cover concerns system malfunctions.

“People always ask me ‘how do you know the system is working,’” he said. “I say to them ‘You can tell when you see that the plants aren’t dead.’”

On large slopes, CDIS is laid out in 6-foot by 6-foot grids by a crew of five to six installers. More than 25,000 square feet of land can be watered using the 6-foot by 6-foot grid. The grid includes two drippers and a one-inch valve. Approximately 21 gallons of water per minute can be delivered to the site via the grid.






While much of the Redhawk drip irrigation project uses the 6-foot by 6-foot grids, some areas of the project utilized grids of 3-feet by 3-feet and 2-feet by 2-feet. The 3-foot by 3-foot grids are used on some of the flat areas at the bottom of slopes and near retaining walls at the housing development.







Gross said the grid system is redundant and can be installed easily and quickly by the crewmembers.

“The grid lays out almost as fast as an overhead irrigation system,” Gross said. “Much of the material is pre-assembled and taken to the job site. We can do 1 1/2 to two valves a day.”

The project in Temecula, a residential community called Redhawk, features 24 stations, and about 24,000 square feet of grids. It took crews about one week to place this grid. Gross noted that he uses Bowsmith’s SL220 drip emitter that produces two gallons of water per minute because of its reliability. This drip emitter has a failure rate based on a 10-year cycle. Gross also uses Salco feeder tubes cut in three-foot increments and Senninger regulators.

During installation of the irrigation system, Gross first lays out the grid pattern. Then, the system is hooked up to the water supply and water is run through the system for several hours. After the water is turned off, Gross determines the placement of the plants and trees.






The CDIS grid lays out almost as fast as an overhead irrigation system, because much of the material is pre-assembled and taken to the job site. Crewmembers spray paint markers on the slope to outline where the grid will be placed.


“This is different from many projects, where the plants and trees are placed first and the irrigation system is installed around these plants,” Gross said. “With the CDIS, the drip grid (installation) supercedes the plant palette.”

Gross said the Redhawk project uses drip irrigation because the county where the project is located, Riverside County, did not want to use pumps on reclaimed water. The county’s architect drew up a drip irrigation plan that Gross believed would not work very well. Fortunately for Gross, he knew several officials in Riverside County who allowed him to present his CDIS plan.

“I was lucky,” Gross conceded. “I was in the right place at the right time, but I knew that I had a drip system that works.”

Gross said he was given the opportunity to try his plan, without county intervention, with the caveat that if CDIS didn’t work, he would have to change his drip system to conform to the architect’s specifications.






Much of the material is pre-assembled at Sunshine Nursery’s shop and delivered to the job site. When crews arrived at the job site, they selected a bundle of 12-foot PVC pipes and began building the grid. Grid construction is redundant and can be completed quickly.


“As it turned out, my plan worked very well,” Gross said. “The architect’s plan was used on another parcel and it didn’t work as well, so the county went with CDIS.”

One major difference in the drip systems involved the formation of the piping. With CDIS, all of the pipes flow downhill, which makes flushing of the pipes easier. The architect’s plan had pipes that ran uphill and downhill. Gross said uphill piping makes it more difficult to flush the system and could lead to water not circulating efficiently.

While much of the Redhawk drip irrigation project used the 6-foot by 6-foot grids, some areas of the project utilized grids of 3-feet by 3-feet and 2-feet by 2-feet.

“We used the two-by-twos under some of the planters, and two-by-two is as small as you want to go for a grid,” he said.

The upfront costs for CDIS are a little higher than some other systems, but Gross noted that these costs are recovered by the lower maintenance requirements and reduced water bills that result from less water usage.

“The county of Riverside has an allocation of 56 inches of water per year to ‘water’ approximately 420,000 square feet,” he said, adding that a review of the water bill exposed their savings after CDIS was installed. “They discovered they were only using 13 inches per year. The 56 inches the county was allocated is based on watering 100 percent of the area in a 12-month period on overhead.”

Gross added, “with CDIS, you have a uniformed pattern on a 6-foot by 6-foot grid, while applying water to 100 percent of the area with one emitter every 36 square feet. It is easy to understand how you can use 13 inches of water where it takes 56 inches to sustain plant life.”



Search Site by Story Keywords



Related Stories



June 16, 2019, 10:39 pm PDT

Website problems, report a bug.
Copyright © 2019 Landscape Communications Inc.
Privacy Policy