Water-use decisions made easier with computer software

From a conference room at Fresno State University, Guillermo Valenzuela took a virtual trip to his home country of Chile, a country that—like California—battles periodic droughts and the need to capture and deliver water wisely.

"We're very similar to California," Valenzuela said. "We rely on water from snow in the Andes, we have a valley and, in our case, that water can go out to sea in just five days."

He used a laptop computer during an interview to access information on a huge reservoir monitored by the company for which he does marketing and sales, WiseConn. On a large screen in the conference room, he pointed to data that showed exactly how many acre feet of water were moving into and out of that reservoir.

A map showed a canal system much like California's, similarly monitored by WiseConn.

The technology for WiseConn's Web-based DropControl uses a telemetry system with software that can be viewed remotely to help farmers, miners and managers of irrigation districts make decisions on water use and movement.

Founded eight years ago, WiseConn has only recently begun expanding into the California market with activities that include pilot projects with the Madera Irrigation District and on a 20-acre plot of olives grown for oil at Fresno State.

Valenzuela was among presenters at a seminar at Fresno State's Center for Irrigation Technology on water use efficiency using the Web.

The center's education specialist, Bill Green, opened the program with some stark observations on the need to use water wisely in what is shaping up as one of the driest years in decades for California.

"That's a pretty bleak picture," Green said, speaking literally, not figuratively, as he showed the contrast between aerial views of the San Joaquin Valley and the Sierra taken Jan. 13, 2013, and on the same date this year.

"You see very little snow this year and not much green growth," he said.

The water shortage is expected to mean the fallowing of thousands of acres in the state, he said. A raisin grape grower himself, Green has personally felt the impacts of having to upgrade a pump because of a drop in groundwater levels.

This will be the first year WiseConn's automated monitoring and water delivery system, installed by Western Ag & Turf in Madera, will be fully applied to the olive trees at Fresno. Speakers said it was only used manually last year and that irrigation applications fell well short of what was needed to optimize yields.

The hope is that moisture sensors from Sentek Technologies, used in the WiseConn system, will enable early detection of water stress on the trees while guarding against using too much or too little water during irrigation.

WiseConn has operations in Chile, Argentina, Peru and Mexico on 40,000 acres of farmland, in 15 irrigation districts and on three mining sites.

Mining accounts for a significant percentage of exports from Chile, and the company's irrigation applications are used to extract minerals that include copper.

On farms large and small, Valenzuela said the Web-based system is important "for managing the water we have, to be sure the pump is running when it is needed."

In South America, he said, the system has saved water and energy while boosting yields and cutting labor costs. He said water savings could amount to 30 percent and energy savings of up to 20 percent.

DropControl is a wireless network made of nodes, which are connected to sensors and actuators for monitoring weather conditions, soil moisture and historic data on irrigation.

"The system has a hydraulics logic built in, "Valenzuela said. "If I'm a pump, where do I get my water from? Do I have water in the reservoir?"

Participants in the seminar visited the olive plot where they saw equipment powered by solar panels and heard the system roar into operation as WiseConn CEO Cristobal Rivas clicked on an I-pad. He said he could control and monitor the system from any device that can access the Web, including a smart phone.

Accessories that can be part of the system include weather stations that measure rainfall and evapotranspiration, soil moisture monitors and flow meters. The system can be used in fertigation, as well.

Expansion boards that are used to control the system enable having a half dozen variable applications of water in fields as small as 8 to 10 acres.

Valenzuela said the system leaves control of irrigation in the hands of farm managers, who may often be heavily burdened with decisions on workers, machinery and other issues, particularly at harvest time.

David Little, U.S. regional manager for Sentek, said it is important to "trust but verify" what the telemetry system is telling you about moisture levels. That means knowing the type of soil you have and in-the-field observations on what is happening.

He explained that measurement of moisture is limited to four inches around the probe, a tube that can be inserted as much as two meters into the soil.

Little said how that insertion is made is important. He recommended against auguring out too much soil, then inserting the probe into a slurry of water and soil taken from the ground. That, he said, means readings of a uniform level, not layers of different textures.

Little said the preferred method is to augur a hole slightly smaller than the probe, then drive the probe into that hole.

Users of the probes need to keep an eye on them to be sure they are not damaged, he said. But he said he knows of vineyards where the same probes have been in place for 20 years.

Little said the top of probes can be removed without digging them out when servicing or reconfiguring is needed, but it is important to be sure they are water tight.

(Dennis Pollock is a reporter in Fresno. He may be contacted at agcompollock@yahoo.com.)