Founded in 1951, the Central California Irrigation District (CCID) is a member of the San Joaquin Exchange Contractors Water Authority, which services approximately 240,000 acres of prime agricultural land in central California. CCID provides water to more than 1,600 central valley farms on more than 143,000 acres.
These systems deliver the accuracy we need with little maintenance. They’ve been a reliable alternative for us.
John Relvas, SCADA Specialist, CCID
By Helen Taylor
Large irrigation district adds low-maintenance Doppler sensors to its monitoring mix
Seeking a flow monitoring alternative for areas where mechanical meters were problematic, the Central California Irrigation District found an affordable and reliable solution with AgriFlo XCi meters and Doppler insert velocity sensors.
From its point of origin at Jones Pumping Plant, The 117-mile long Delta Mendota Canal in central California delivers water from the Sacramento-San Joaquin Delta to the Mendota Pool in the San Joaquin Valley, where it travels through a 500-mile network of gravity-fed canals maintained by the Central California Irrigation District (CCID) to its final destination: the fields of more than 1,600 central valley growers.
CCID is charged with monitoring hundreds of turnouts, making sure irrigation water arrives at its destination unimpeded and canal operators have the information they need to anticipate demand through the growing season.
For decades the district largely relied on mechanical propeller meters to monitor flow at diversion points along the canals. CCID SCADA Specialist John Relvas says that the meters were readily available and typically performed well. But at several locations, routine maintenance was required to ensure the propeller meters performed to district standards.
CCID sought a suitable alternative to monitor flow in sub-surface, reinforced concrete pipes ranging in size from 24 to 72 inches. They found what they were looking for in the AgriFlo XCi and Doppler Insert Velocity Sensor. The sensor uses continuous-wave, advanced-spectrum Doppler to “see” velocity through the entire cross section of the pipe and calculate a true average flow rate.
To date, CCID has installed about 20 AgriFlo Series 3 meters, and about half of them monitor three sensors from a single box. At two canal-control locations, CCID went a step further and added a telemetry interface card with a Modbus output that integrates with the district’s SCADA system. A PLC regularly interrogates the meter for data and sends it to the SCADA, where specialists like Relvas can view it in real time.
“These are locations with diversions from one canal to another, so they’re critical to canal operations,” says Relvas. “It’s very beneficial to be able to just click on the two sites and see accurate data in real time.”
Relvas says that canal staff and growers interact with the other AgriFlo units at the local level, collecting accurate data right off the meter. Because the sensors are inserted into the pipes underground and the AgriFlo boxes are contained in mounted electrical enclosures, the equipment is virtually maintenance free and protected from weather and vandalism.
Since putting in its first AgriFlo units more than a decade ago, CCID has upgraded to the latest In-Situ MACE technology and seen solid performance across the board.
“Installation of the sensors below grade was more involved than installing propellers,” Relvas says. “But the propellers often require more field visits, and the maintenance schedule for electric meters is heavier. These systems deliver the accuracy we need with little maintenance,” he adds. “They’ve been a reliable alternative for us.”
Water supply ranks high among California’s environmental concerns, and CCID makes a concerted effort to demonstrate responsible management of the resource.
“We decided a long time ago that precise water measurement was prudent and necessary,” says Relvas.
With the recent passage of state legislation requiring a higher degree of accuracy in water measurement, CCID is well-positioned to meet those more stringent requirements and serve as a model for the state.