The District canal system starts at the Winters and West Adams headgates where water released from Cache Creek and Indian Valley Dams is diverted into the canal system by the Capay Diversion Dam. Approximately two-thirds of diverted water goes into the Winters Canal, the District’s largest. It carries water to the south of the diversion dam and offshoots to many canals such as the Cottonwood, Yolo Central and Pleasant Prairie Canals. The West Adams Canal runs to the north of Cache Creek and services the Hungry Hollow, Clover and Moore canals, among others.
Headgates are the points where water is moved from one canal to the start of another canal and the headgate regulates the flow of water into the branched canal. The amount of water moved is regulated by opening and closing a gate valve. In the past this was all done by hand, but with grant funding the District has been able to replace almost 30 headgates with automatic flow control gates. These gates automatically open and close to regulate the flow from one canal into the next. This not only saves staff time, but they also make it possible for farmers to receive water in a more timely manner, because staff can make adjustments from a computer at any time.
All of the canals are gravity fed with no pumps, which means that in many places water pressure needs to be built up along the canal to provide enough ‘head’ to effectively deliver water to the farmer’s field. This is accomplished by using a check structure, or a little dam within the canal, to raise the upstream water elevation. The District has over one hundred check structures within the system. The water level behind the check structure is regulated by inserting wooden boards, which ditchtenders insert or remove by hand to adjust the water level in the canals to the desired level.
There are also hundreds of delivery gates throughout the canal system; this is the point where growers receive water to irrigate their fields. These gates are operated, maintained and replaced by the operations and maintenance staff.