Call it smart irrigation.
The South San Joaquin Irrigation District is considering replacing canals serving 72,000 acres of farmland in Manteca, Ripon, and Escalon with a pressurized delivery system controlled by computers that would arm ditch tenders with tablets and growers with smartphones.
It would replicate the successfully pressurized system put in place in Division 9 south of Manteca and west of Ripon two years ago. It has allowed growers who had been using groundwater with high salinity levels that can ultimately render soil sterile to take water instead from the SSJID system.
Normally that would trigger major delivery and supply issues for existing irrigation customers. But instead of taking longer to flood irrigate or not having enough water, the pressurized system cut flood irrigation time in half as well as eliminated all spillage back into the river.
That, coupled with a three-year investment of $4.5 million to help farmers throughout the district implement more efficient farming practices, has saved the district over $3.5 million so far. Both the growers’ conservation program and the Division 9 pressurized system also saved enough water to allow SSJID to net $4 million more in out-of-district water sales to other water purveyors.
Should the district ultimately switch to a pressurized system it would make more water available for domestic use in the cities of Manteca, Ripon, Escalon and Tracy as well as free up more water for sale to other locations in California. It would effectively increase the district’s water supply by eliminating spillage as well as water waste. The pressurized system allows growers to use high efficient drip systems to get water to trees. Those closed systems also allow the intermixing of chemicals to further reduce costs and time by directing fertilizer and other nutrients directly to trees.
One potential drawback is a pressurized system could ultimately mean less water recharging underground aquifers. Some 40 percent of the 250,000 acre-feet of the water the SSJID imports from the Stanislaus River watershed ends up recharging aquifers. Most of it is through seepage at Woodward Reservoir as well as from losses in canals and storage basins. But a sizeable amount is also attributed to flood irrigation. If pressurized delivery was available district wide, it would make the placing of drip irrigation financially feasible allowing flood irrigators to switch. Adequate pressure would mean growers wouldn’t need to employ expensive pumps that consume thousands of dollars of electricity monthly for even a relatively small almond orchard.
The Division 9 pressurized system has significantly reduced pumping of all types, cutting electricity use as well as air pollution since many farmers used diesel engines to operate pumps.
Such a system districtwide would have the net effect of securing more water for domestic and farm uses by eliminating waste, significantly reducing water evaporation, and making what water is applied to crops as efficient as possible.
The SSJID board during a special meeting Monday authorized spending $750,000 to have experts conduct a system wide study on the concept, examine the feasibility and determine the cost of implementing such a system. The money for the study essentially was gleaned from water sales to other districts from water saved through pressurized delivery in Division 9 over the past two years.
Such a study is expected to take a year to complete.
