Highly treated water gives irrigation boost to growers

A growing number of the state's farmers are turning to highly treated, recycled municipal water as one more source for irrigating their crops.

As early as late this year, treatment plants in Modesto and Turlock will begin sending irrigation water to growers on more than 40,000 acres in the Patterson area, and that project should ramp up to 35,000 acre-feet by 2018.

The largest recycled irrigation water program in the world, the Marina plant serving growers in coastal areas of the Salinas Valley, finds demand from farmers so strong it is working on an expansion plan.

"At 15,000 acre-feet, we are the largest supplier of recycled water to agriculture in the world," said Bob Holden, Monterey Regional Water Pollution Control Agency recycled water project coordinator. "The second largest is in Watsonville, a few miles up the coast."

Holden made his remarks in Sacramento during the 55th annual conference of the California Irrigation Institute, the most important event of the year bringing together agricultural and urban water users and suppliers.

The theme of this year's conference was "Managing our Water Checkbook: Solutions for a Balanced Bottom Line." A number of water agency representatives said they believe part of the answer can be achieved by sending recycled water from cities out to irrigate nearby farms.

"We have farmers lined up wanting to get into our project," Holden said. "We don't have enough sewage water, so the county installed an inflatable dam on the Salinas River, which they inflate in April. We take the water up to our plant, disinfect it and mix it with our recycled water. The growers insisted that it be disinfected, so it would be as high quality as the recycled water."

The process for turning waste into safe, high quality irrigation water involves a complex use of filters, machines and chemicals.

"We have to put it through the tertiary treatment process," said Richard Gilliam, operations supervisor, during a tour of the Monterey Regional Water Treatment Plant in Marina. "We treat it with chemicals and flocculate the water to aggregate the solids so we can capture them with filters. Then we disinfect the filters. It does cost money to take it to the third stage."

The expansion of the project that sends water to growers in the Castroville area, who use it to decrease pumping to slow down the advance of seawater into the underground aquifer, could come as soon as later this year.

"We're hoping to break ground this year on facilities to capture water, treat it and put it into the ground when there is enough rain that the farmers don't need it," Gilliam said.

When the Marina project started less than 20 years ago, many were skeptical, but today farmers have come to see the value this high-quality water has brought to coastal agriculture.

"Before we came online, the area was largely artichokes," Holden said. "Now, farmers can grow row crops including broccoli, cauliflower, celery, lettuce and even strawberries, which can bring $66,000 an acre."

The project is in such demand that the Monterey County agency plans to collect a combination of water from agricultural tile drainage, industrial water from Salinas, and storms during the winter, treat it and send it out to the farms when it is needed.

"We are going to put this into ponds and then treat and pump it in the summer, essentially turning winter water into summer irrigation water," Holden said.

The Marina project has made believers even out of skeptics in the viability of irrigating with recycled water.

"They are on the cutting edge of using water from all sorts of sources for fresh produce. I think we're all going to have to look at what they're doing," said Chase Hurley of the Henry Miller Reclamation District in Dos Palos.

Hurley toured the Marina plant on behalf of farmers in the Dos Palos area, who would be downstream from another recycling project that may soon wrest the mantle of the world's largest.

The Del Puerto Water District serves Patterson-area farmers on 45,000 acres. Farmers in the area have no choice in dry years but to pay high prices for supplemental water to keep their permanent crops alive.

"Our main source of water is the federal project," said Adam Scheuber, Del Puerto Water District water operations resource manager. "There aren't too many low-value crops because supplemental water in drought years is $200 to $800 an acre."

Faced with those prices, district farmers struck a bargain with treatment plants in Modesto and Turlock, which are scheduled to begin sending recycled water to the Del Puerto District late this year.

"North Valley water will be three to four times as much as Central Valley Project water, but that number should come down and it is more reasonable than supplemental water," Scheuber said. "As the cities are able to provide more water, that number will come down. Developing this source of water will increase the value of the land in our district, and increasing the surface supply will also reduce groundwater pumping."

For their part, the Modesto and Turlock districts will be able to avoid the nettlesome problem of gaining permission to discharge into the San Joaquin River.

Recycling also provides the answer for Sonoma County water treatment agencies looking for a place to send their effluent.

"Our first user of recycled water in 1990 was a dairy farmer, and we had to pay him to use that water," said Pam Jeane, Sonoma County Water Agency assistant general manager for operations. "Now the farmers pay us, and it includes a lot of premium winegrape growers who don't have access to enough water. It is very high-quality water."

Sonoma County farmers, too, have come to believe in recycled water, and the agency has contracts for 95 percent of its discharge.

"If you are in an area with seawater intrusion, our recycled water has a lot less salt than your groundwater," Jeane said. "We have thousands of acres of grapes using recycled water. The dairy farmer we had to pay to take the water has converted that land to grapes."

(Bob Johnson is a reporter in Davis. He may be contacted at bjohn11135@aol.com.)