Farmers and landscapers in South County may soon have a new tool
to assist them in maximizing the efficiency of crop irrigation. The
Santa Clara Valley Water District is working on a proposal to build
and maintain a specialized weather station in San Martin to collect
data that would be useful to farmers in fine-tuning their
irrigation schedules and, as a result, conserving water.
Morgan Hill
Farmers and landscapers in South County may soon have a new tool to assist them in maximizing the efficiency of crop irrigation.
The Santa Clara Valley Water District is working on a proposal to build and maintain a specialized weather station in San Martin to collect data that would be useful to farmers in fine-tuning their irrigation schedules and, as a result, conserving water.
The district’s board of directors voted against a proposal for the weather station which came up at a board meeting in late November. The board asked the staff to come back with a “more creative” proposal, according to SCVWD assistant engineer Bob Siegfried. He noted board members were concerned with the projected $600,000 cost of the weather station.
Staff proposed a facility that would be integrated into the California Irrigation Management Information System, which consists of about 130 similar weather stations throughout the state, Siegfried said. The proposed site of the weather station is on an undeveloped five-acre parcel at 1005 East San Martin Ave. The district acquired the property in 1970 for flood control purposes. It was deeded to the district at no cost through a condemnation action by the state of California.
The project would gather detailed data on humidity, wind direction, air pressure and other factors, which would be mathematically modeled to measure daily crop water use and help farmers and growers determine exactly how much water to use, Siegfried explained. He said the data provided by the weather station is “fundamental” for accurate irrigation scheduling, which can improve water conservation.
“Water use could be mathematically related to the weather station,” Siegfried said. “If the data is properly used, it will save water, which is increasingly in short supply.”
He noted the staff has not produced an estimate on water savings the station could achieve, but he said just “tuning up” existing irrigation systems throughout the valley could save as much as a third of a foot of water per acre per year, which is roughly equivalent to 100,000 gallons per acre per year. Santa Clara County has more than 20,000 acres of agricultural property, most of which is in South County.
In a recent study by the National Agri-Marketing Association at the University of California, Davis, 23 percent of participating growers increased their crop yield using CIMIS.
Siegfried added that the district will soon partner with the county’s Farm Bureau for a year to provide technical assistance on irrigation scheduling to farmers in the area.
The data compiled by the weather station would be available at the end of each day on two Web sites, one operated by the state department of water resources, and one by the SCVWD.
A large part of the project’s expense consists of drilling a well, planting turf grass and installing an irrigation system, all of which are necessary to generate the most precise estimates of water use. Siegfried said the turf provides a reflection and a “wavelength of sunlight” that is observed by the computer models, and it provides a level of humidity that is similar to that found at other agricultural sites.
“Within that reflection and humidity environment, the weather station is taking measurements,” Siegfried said. “The amount of water used by any other crop (in addition to turf) can be related to the numbers this model spits out.”
Nicole Morneau, manager of the Santa Clara County Farm Bureau, said the project would benefit local farmers, several of whom she said have used a similar weather station at Live Oak High School, which was operated by the district before it was taken offline due to development on the campus.
She said proper irrigation scheduling is important to avoid over-watering but also to ensure crops get enough water. Furthermore, knowing the wind direction and speed will help determine the best time to apply pesticides.
The program to work with the district will start in a few weeks, Morneau said. The Farm Bureau will identify 10 growers throughout the county and evaluate their irrigation systems. “We’re going to look at leaks, waste water issues, and distribution uniformity, to help them achieve 80 percent efficiency” in irrigation, Morneau said.
District staff believe the yearlong program, which will cost $110,000, could identify methods to save up to 6,000 acre-feet of water per year. One acre-foot of water is enough to provide water to a suburban family of five for one year.
Siegfried added that the weather station and other efforts to irrigate more efficiently could lead to financial savings for the farmers. “If you pump less water, you use less electricity, and you pay less on the groundwater reduction fee that’s paid to us,” he said.
The weather station could also provide “bomb-proof” evidence for farmers to show they are in compliance with water quality control guidelines, Siegfried said.
“I personally understand the board’s concern for the cost. We’ve somehow got to find out a more creative solution,” Siegfried said.
The SCVWD provides water and flood protection to 1.8 million residents. It employs 825 people and has an annual budget of $411 million.
