Lack of water is a painful reality for California residents and businesses. In 2013, as the state experienced the driestt year on record, Altman Plants dusted off a water reclamation plan it had been contemplating for a few years.
“We were concerned with the long-term water supply, concerned with the rising cost of water, and wanted to make sure we were protected against a short-term interruption of supply,” says Jim Hessler, Altman’s director of West Coast operations.
In 2014, construction began on the large-scale water reclamation system at the grower’s Lake Mathews location in Southern California’s Riverside County. The Lake Mathews site houses 420 acres of container production and relies solely on municipal water to irrigate plants. Altman constructed a new on-site storage facility, lined an existing reservoir, installed two pumping plants and a treatment facility.
The nursery is designed to capture all the runoff from the container beds. All beds are covered with ground cloth, and most beds have plastic under the ground cloth. Irrigation runoff flows via gravity into three ponds through a system of channels and canals, then ends up in a 10-acre-foot basin at the lowest point in the nursery. The canals and channels are also lined so the nursery doesn’t lose any water.
First, irrigation runoff is captured in the remedial pond. Next, runoff travels to a second pond complete with natural vegetation of cattails and barley to help mitigate excess nutrients and algae. As water travels through the main canal, canna boxes help remove nitrates and fertilizer runoff.
“The main canal is the backbone that everything feeds into, and it’s almost 2 miles from end to end, with many more miles of small channels feeding into it,” Hessler says.
Water is stored in a third holding pond prior to undergoing sand filtration and acid injections to lower pH. Water is stored in the final holding pond and treated with chlorine dioxide to control pathogens prior to reuse.
“We test the water right past the pumps and test it at various locations throughout the nursery for the right amount of chlorine dioxide,” Hessler explains.
On a really hot day when water needs are high, the nursery can generate about 1 million gallons of water. Since the launch of the reclamation system, Altman has recycled about 200 million gallons of water. And the water savings from the system has exceeded Altman’s goal by 5.5 percent.
“Our engineering was better than we thought it would be,” Hessler says. “Our field design, channel design, the way we train the irrigators, and the maintenance of the entire irrigation system have all played a role. Up to this point, we thought we’d recycle and remediate about 100 million gallons, and it ended up being double that. We still use municipal water, just a lot less of it.”
Hessler adds that two key players in the success of this system are the facilities manager and the technical services manager, who are watching the system on a daily basis.
A large cultural change took place in regards to irrigating once the system was operational.
“In most jobs throughout the nursery, the more you do, the better — sales, planting, or weeding. It’s the opposite with irrigating, and there was a lot of education that went into training irrigators how much water needed to be applied throughout the nursery,” Hessler recalls.
The majority of the nursery uses overhead irrigation, and Altman has changed to more efficient sprinklers.
“This has been an evolving system,” Hessler says. “And because municipal water is not the ideal quality for plants – high pH, high alkalinity and high EC – we’ve had to develop techniques for growing with less-than-perfect water. The water we use impacts our selection of soils and it’s also a factor in our choices of fertilizers for certain crops.”
To complement the reclamation system, Altman is installing sensors in every field to monitor soil moisture. Each field, which is generally one-third of an acre, will have one or two moisture sensors, depending on plant material and container sizes. Based on data from the sensors, the nursery will prioritize the areas that need to be irrigated first. About a quarter of the nursery is equipped with the sensors, and another quarter is almost complete. With the sensors in place, the nursery discovered that over a four-week period, it saves three irrigation applications, and each application equals about 4,000 gallons of water, Hessler says.
Prior to the reclamation system, Altman used basins to capture the runoff, but the nursery was unable to reuse the water. And five years ago, the nursery cut its water use in half.
“Being mindful of the need for water conservation and being on the leading edge of water conservation research is part of our DNA,” he adds.
For more: www.altmanplants.com