Jun 18, 2015

Drought forcing California to find water alternatives

From using reclaimed water to a computerized canal delivery system, water managers are being pushed by California’s four-year drought to look at innovative ways to stretch meager supplies.

A.G. Kawamura, a partner in the family owned Orange County Produce, said the operation has successfully used reclaimed water for more than 20 years to irrigate its produce crops.

Over the years, the Irvine Ranch Water District, which serves growers including Orange County Produce, has increased the amount of reclaimed water it provides to 21 percent of total deliveries. The bulk goes to agricultural and landscape uses.

The reclaimed water must undergo tertiary treatment and disinfection and meet strict standards, said Kawamura, who is a trustee on the Southern California Water Committee and California WateReuse Foundation, and a former California secretary of agriculture.

“The water is really good quality, and in many cases better than well water,” he said.

Nevertheless, the unusually dry weather of the past four years has caused salt buildup in the region’s soil, he said.

Growers typically rely on winter rains to help push salts in the soil below the root zone.

Groundwater and Colorado River water, which are being used more heavily, naturally have higher salts than mountain-fed water coming through the State Water Project.

“So salts are rising in all categories – out of wells, just the flow of water coming through the system – and we’re not getting much state water down here any more,” he said.

The Department of Water Resources, which operates the State Water Project, announced allocations of only 15 percent this season for Southern California water providers.

Faced with the second consecutive year of zero federal water allocations, growers in the Del Puerto Water District on the San Joaquin Valley’s west side hope they can survive until the North Valley Regional Recycled Water Program is completed.

“We’re struggling to find any available (water) supplies,” said Anthea Hansen, district general manager.

The district’s Central Valley Project’s maximum contract amount is about 140,000 acre-feet for use on about 45,000 acres. But it hasn’t received full allocations in more than a decade due to drought and San Joaquin Delta water quality regulations.

Growers fallowed about one-fourth of the district’s ag land in 2014, and Hansen said she expects it to be worse this season. Most growers have sacrificed row crops to save what little water they have for their permanent crops.

The North Valley project would convey reclaimed water from treatment plants serving Turlock, Modesto and Ceres to growers in the Del Puerto district.

The district is in the process of completing an environmental review, Hansen said. If all goes according to schedule, construction of a pipeline to transport reclaimed water could begin in late 2016, with completion scheduled for 2018.

Initially, it would deliver about 30,000 acre-feet of reclaimed water to the district near Patterson. As the cities grow, the deliveries could eventually reach about 59,000 acre-feet, she said.

To help water districts or cities that may consider recycled water programs for agriculture in the future, researchers from the University of California, Riverside (UCR), and the Hebrew University of Jerusalem have embarked on a two-year study. The researchers said they hope the work will lead to viable and cost-effective regional water reuse policies.

Kurt Schwabe, a UCR associate professor of environmental economics and policy, will lead the group, which will review existing research on using reclaimed water to improve the reliability of local water supplies. Much of the data will come from California and from countries such as Israel that have been using reclaimed water more than a decade.

Part of the project will examine how the recycled water affects crop yields and evaluate cost-effectiveness of new wastewater treatment technologies for landscaping and agriculture, Schwabe said.

The research also will look at specific crop requirements and how wastewater treatment might be engineered to meet those individual needs.

The project initially is being funded with a $300,000 USDA seed grant.

The Oakdale Irrigation District (OID), which serves municipal users as well as about 72,000 agricultural acres, has taken a different approach to stretch its water supply. Four years ago, it had two fully automated computerized canal control systems from Colorado-based Rubicon Water installed.

“The Rubicon is a very attractive system to implement here,” said Steve Knell, OID general manager. “It gives water to the farmer in the amounts and rates he needs so he can do a better job.”

The system was developed in Australia, where similar systems have been in place for more than 10 years, said Damien Pearson, Rubicon’s general manager for North America.

“The irrigation networks in Australia are similar to those in North America, and Australia had had a very severe drought that researchers believed was the worst in 1,000 years,” he said. “In response to that, the system that was adopted by Oakdale was rolled out through an 840,000-acre growing region.”

Oakdale marks the first implementation of the technology in the United States, Pearson said.

The system on Oakdale’s 6.5-mile Claribel lateral, which has 17 pools and supplies water to about 75 farmer service points, monitors and precisely controls levels from the supply point to each farmer’s turnout.

Before the system was installed, more than 1,700 acre-feet of water spilled annually. An acre-foot, about 326,000 gallons, can meet the annual water needs of a family of four or five, according to the Department of Water Resources. During the past four years, the automation has eliminated that spillage.

“We’re very impressed with the technology and its ability to manage a ditch system without human input and move water up and down all day long,” Knell said.

At the same time, another Rubicon system was installed on the 8.5-mile Cometa lateral, which has 21 farmer turnouts. The long canal, with a slope of 0.8 percent, also has two separately managed downstream districts. Getting water to those districts was always a challenge.

“It was either feast or famine,” Knell said.

The automated system has helped provide more consistent flows along the lateral.

“For the growers who were in that (downstream) division, it provides better service. Every time you give farmers better service, they irrigate better,” he said.

– Vicky Boyd, VGN Correspondent