Water district shows growers that treated water works just as
well as traditional sources
In the latest effort to prove the efficacy of using reclaimed
water to irrigate local crops, the San Benito County Water District
last week displayed the bounty from a five-acre test plot grown
with water from Hollister’s wastewater treatment facility.
Water district shows growers that treated water works just as well as traditional sources
In the latest effort to prove the efficacy of using reclaimed water to irrigate local crops, the San Benito County Water District last week displayed the bounty from a five-acre test plot grown with water from Hollister’s wastewater treatment facility.
Tomatoes, leafy greens, squash and beans were grown by local grower and water district board member Joe Tonascia at 460 Briggs Road, between Briggs and Flynn roads, near the Hollister Airport. This field trial followed a smaller-scale pilot study conducted at the city-owned grassy park formerly owned by the Brigantino family on San Juan Road.
“Having done the trial, I don’t see any problems whatsoever” with using the treated water, Tonascia said.
The water was pumped to the site through the city’s 14-inch reclaimed water distribution line, which runs to a field near the airport where treated water is sprayed.
“It showed that the crops are going to grow just as well,” Tonascia said.
The same crops were grown using groundwater and reclaimed water to help the water district compare how the vegetables responded to both types of irrigated water. Samples were taken every few weeks during the growing season.
“We want to show growers how well this water will work,” said Jeff Cattaneo, director of the San Benito County Water District. “Tests have shown that there is no issue with pathogens in the tissue sampling.
“You can see no difference between the crops grown by groundwater and the water that produced this crop,” he told a gathering of growers, water board members and local elected officials last Thursday.
District officials want to show growers that the benefits of using the treated wastewater include the predictability of the supply as well as its quality.
Deputy District Engineer Dale Rosskamp anticipates that the treated water would “probably cost the same” as the San Felipe Project water that some growers now purchase and “it’s a known quantity coming out of that plant limited only by the amount the plant can produce.”
Groundwater typically has more nutrients from fertilizers that have leeched into the underground aquifer from which it comes, while the treated water has less hardness, Rosskamp said.
One of the biggest expected hurdles to growers choosing to use the treated water to irrigate their crops will be a psychological one, water district officials said.
“They’ve been using it for 20 years in Castroville and for about five years in Watsonville,” Rosskamp said. “When something is new, people are a little leery of it. (The treated water) has predictability and quality and no pathogens. Eighty five percent of the artichokes consumed in the United States are grown using reclaimed water.”
Castroville uses 22 million gallons of reclaimed water per day to irrigate crops 10 months out of the year, district officials noted. Two million gallons of treated water are produced in Hollister now.
The pilot program has allowed the water district to “get a handle on” what the regional water quality control board would expect in terms of water quality monitoring and testing, Cattaneo said.
“We’ll now be looking at the next steps to build out the full project, from putting a water quality program in place to training growers on how to apply the water to crops,” he said.
A full permit for using reclaimed water to irrigate crops won’t be available for 18 to 24 months, Cattaneo noted.
“It’ll be at least two years before we’ll have anything in place to grow crops for market,” he said.
Tonascia said that if growers can get beyond the “psychological barrier” of using treated water to irrigate their crops, they could have a more predictable supply during an era where environmental restrictions are limiting the supply made available to the state’s growers.
“You have to have water, so if they can produce good water at a fair price, growers will use it,” he said. “We’d also be doing the community a service by putting the reclaimed water to work.”
