The California Sluiceway extends from the 12 radial gates, located between the All-American Canal Headworks and the overflow weir, downstream about 3,000 feet. The sluicing flows usually are 8,000 cubic feet per second released for a 20-minute period, although many different flow rates, time periods, and combinations of gates are used. This procedure also removes some sediment from Imperial Dam Reservoir. Prior to 1964, the sediment from the desilting basins found its way down the river and, as water was diverted from the Colorado River, a disproportionate amount entered the Mexican irrigation system. As a means of resolving this problem, a channel was constructed in 1964 from the end of the California Sluiceway to the reservoir area above Laguna Dam.
Dredges pump the sediment from the settling basin to the adjacent flood plain.
The first dredging operation started in 1965 and has since been intermittently required about every 2 years. The sluicing flows from Imperial Dam are stored behind Laguna Dam and released over extended periods. Laguna Dam releases become part of the water delivered to Mexico. This procedure requires considerable fluctuation of the reservoir elevation, which limits the value of Laguna Reservoir as a recreation resource. The California Sluiceway is also used to discharge excess water flows arriving at Imperial Dam that are not pumped to Senator Wash Reservoir or diverted to the canals.