SCADA Applications & Installations:
Glenn-Colusa Irrigation District - Arts & Sciences
Glenn-Colusa Irrigation District (GCID), the largest irrigation district in Northern California, draws its water primarily from the Sacramento River at Hamilton City 30 miles north of Willows. GCID's delivery system consists of a 65-mile long main canal and 430 miles of laterals. Personnel are working toward bridging the gap between the age-old art of ditch-tending and the more modern science of real-time system operation.
With the demands of 141,000 acres of farming and 20,000 acres of wildlife refuge, GCID services 2,500 turnouts that deliver, on average, 500,000 to 800,000 acre/feet of irrigation water each year. "The goal of the District is to achieve balance in the operation of the main canal," says Gino Romano, Watermaster and Electrical Engineer with GCID. Ideally, balance would mean that the pools along the canal would remain at relatively constant levels during changes in delivery and demand.
The Art
The age-old art of conveying water in earth-lined channels dates back in time to the period when Babylon thrived. Managing water levels in this type of system creates a major challenge, with each pool in a main artery and each lateral having a characteristic of its own. One could say that each of the subsystems within the larger system has a unique personality. To fully understand and operate a complex system like GCID's, one must have an affinity for running water, years of experience and the ability to operate by the "seat of the pants." Water operators must also be able to read the weather, understand the growth patterns of various crops, and "out guess" the needs of the growers they serve. After many years of experience, the water operator develops the ability to assure deliveries to the growers based on limited demand estimates and constantly changing circumstances.
The Science
While water operators and their supervisors still must drive the canal each day to make adjustments, system-wide monitoring at GCID is entering the 21st century. Sensors provide real-time pool levels, flows, remote site power status and other critical information at each point throughout the system. This information is gathered from several sites, many of which are equipped with Control Microsystems' TeleSAFE Micro16 SCADA Controllers, then reported back to the office in Willows via radio telemetry and displayed on a PC using Lookout (by National Instruments) as the "front end" HMI software. From the office, water operations personnel can evaluate pool levels first thing in the morning and make calculations using the real-time information, then head out to the field to make adjustments. This system has already reduced daily driving on the canal by 30%, allowing more time to be spent on other essential duties.
According to GCID retired Controls Technician, George Wall, district personnel have been installing and integrating their entire SCADA system. The district chose Lookout because of its ease of use. By supporting true on-line programming, authorized personnel can modify the program, then immediately test and make corrections as necessary. He also said that the data communications needs throughout the district have been easily addressed through the combined use of their existing UHF radio system and the Micro16 controller, as the SCADA-optimized PLC supports advanced communications features such as dynamic Modbus master/slave switching and store-and-forward communications. The programming of the Micro16 is done using the Windows©-based Ladder Logic Editor which allows an electrician to easily configure communications parameters, program logical control and perform analog calculations. Other unique features found in the Micro16 are its versatile low power requirements (only 5 watts with a modest amount of I/O), responsive factory support, and modular installation.
Combined, the Lookout and the Micro16 will allow the district to easily progress from simply monitoring the canal system's 18 pool levels and power supply status, to actual remote operation of the flow control sites as well as water quality monitoring of the outflow. The future expansion of up to 3 MB of RAM will allow the inclusion of sophisticated C-Language programming capable of handling the algorithms necessary for the complex automatic control of a canal system.
It's clear that the total elimination of the human art of canal operation is far off in the future. However, with newer technologies and products like Lookout and the Micro16, the science can bring greater system efficiency. Remember, the goal is balance. GCID is on to something here.
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Trademark Acknowledgments: Windows 3.1, Windows 95, Window 98, and Windows NT are trademarks of Microsoft Corporation. Modbus is a trademark of AEG Modicon. Lookout is a trademark of National Instruments. TeleSAFE, Micro16, SCADAPack, and TelePACE are trademarks of Control Microsystems. HART is a trademark of the HART ComunicationFoundation. LIQ-IV and LIQ-V are trademarks of Tesco Controls, Inc.
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