The Imperial Irrigation District (IID) receives an average of 3.1 million acre-feet each year from the Colorado River. Imperial Dam, located north of Yuma, Arizona, serves as a diversion structure for water deliveries throughout southeaster California, Arizona and Mexico. The operations of IID's River Division Office at Imperial Dam, as well as system wide water distribution, all fall under the direction of the United States Bureau of Reclamation (USBR). Water diverted at Imperial Dam for use in the Imperial Valley first passes through one of three desilting basins, used to remove silt and clarify the water. Each desilting basin is 540 feet wide by 770 feet long and is equipped with 72 scrapers designed to remove 70,000 tons of silt per day. The silt is returned to the river by means of six sludge return pipes that deposit the silt into the California Sluiceway. From the desilting basins, water is then delivered to the Imperial Valley through the All-American Canal.

Three main canals - East Highline, Central Main and Westside Main - receive water from the All-American Canal and are used to deliver water to many canals that exist throughout Imperial Valley. Farmers then divert water directly from these canals to irrigate approximately 479,000 acres of farmland within IID's boundaries. Another important component of IID's distribution system are the seven regulating reservoirs and three interceptor reservoirs that have a total storage capacity of more than 3,300 acre-feet of water.

IID serves water through approximately 5,600 delivery gates for irrigation purposes. It operates and maintains more than 1,438 miles of lateral canals, 230 miles of main canals and the 82-mile-long All-American Canal. IID also maintains approximately 1,406 miles of drainage ditches used to collect surface runoff and subsurface drainage from 32,227 miles of tile drains underlying 462,202 acres of farmland. Most of these drainage ditches ultimately discharge water into either the Alamo River or New River.

Each October, the USBR asks IID to estimate the amount of water it will need to divert from the Colorado River during the following calendar year. This is commonly referred to as the annual water order. After receiving the notice from the USBR, IID asks the Coachella Valley Water District (CVWD) to submit an estimate of its water needs for the following year. IID's general manager then submits the combined estimates to the USBR. In addition to the annual water order, weekly water orders are also submitted to the USBR. Each Wednesday, IID's watermaster submits a water order to the River Division office for the following week's (Monday through Sunday) water requirement. These water orders are derived from historic and recent orders from the IID's water customers. After the USBR has accumulated all the water orders from all water users on the lower Colorado River, it then prepares a master schedule of flows. The amount of water scheduled on this master schedule of flow is typically the amount of water IID is entitled to unless the watermaster requests a revision at least 72 hours in advance.

Water orders for next-day delivery are accepted by IID from its customers until noon and entered into a computer system by each division. By 12:20 p.m., IID's dispatching unit access the computer for information on the total amount of water orders. By 1 p.m. the dispatching unit allots all available water back to the divisions, places a firm water order to River Division for the following day's water deliveries and requests changes to be made in the master schedule for four days in advance. Using the total amount of water allotted, the divisions call in water orders for each canal heading to the dispatching unit. The dispatcher at the dispatching unit then prepares a water plan for the following day's water deliveries and schedules the required changes throughout the main canal system in order to meet water user demands. The Water Control operator executes all the changes. Then, with the aid of the water SCADA system, water is transported through the main canal system.

Each morning, hydrographers measure and release the required amount of water from the main canal into the heading of each lateral canal scheduled to receive water under the direction of the field operations unit. In addition, every morning, zanjeros (Spanish for "ditch riders") receive a "run" schedule with instructions on where and when delivery gates should be opened or closed for water delivery within a run. Runs are comprised of a set of canals and all the associated customer delivery gates within a geographic area. From the lateral canals, zanjeros measure and divert the required amount of water from the lateral canal through individual customer delivery gates.