Imperial Diversion Dam


Imperial Dam and Desilting Works span the Colorado River 18 miles northeast of Yuma, Arizona. The purpose of the dam is to raise the water surface 25 feet and provide controlled gravity flow of water into the All-American and Gila Gravity Main Canals. The desilting works remove most the sediment carried by the Colorado River to prevent clogging of the canals and subsequent extensive maintenance.

Imperial Dam is a reinforced concrete structure of the monolithic slab-and-buttress type consisting of an overflow weir, canal headworks at each end of the dam, and a sluiceway between the All-American Canal Headworks and overflow weir. The dam is 3,475 feet long, including a 510-foot rockfill dike at the Arizona end. The 1,198-foot-long overflow weir, in conjunction with the California Sluiceway, is designed to pass a maximum flood of 185,000 cubic feet per second, not including any diversions to the canal systems.

RegionFacilities in Lower Colorado | Lower Colorado Home Page
StateCalifornia and Arizona
CountyImperial, CA; Yuma, AZ
ProjectBoulder Canyon
Dam TypeConcrete slab and buttress, ogee weir
WatercourseColorado River
LocationOn the Colorado River, 18 miles northeast of Yuma, Arizona
Original Construction1936-1938
Modified Construction
National ID NumberCA10159
Hydrologic Unit Code

Structural Height85 ft
Hydraulic Height (Normal Operating Depth at Dam)23 ft
Top Parapet (Elevation)197.0 ft
Spillway Crest Elevation
Crest Elevation196.25 ft
Crest Length3,475 ft
Crest Width12 ft
Base Width76 ft
Volume of Dam Construction Materials196,800 cu-yds
Streambed at Dam Axis
Top of Exclusive Flood Control Pool (Elevation)
Top of Joint Use Pool (Elevation)
Top of Active Conservation Pool (Elevation)
Top of Inactive Conservation Pool (Elevation)
Top of Dead Storage Pool (Elevation)

Hydraulics & Hydrology
Total Water Storage at Elevation
Maximum Water Surface Elevation
Normal Water Surface Elevation
Spillway Type Overflow ogee weir
Spillway Capacity at Elevation 180,000 cfs
Auxiliary Spillway
Auxiliary Spillway Capacity at Elevation
Uncontrolled Spillway Capacity at Elevation
Outlet Works Capacity at Elevation6000 cfs at 166 ft
Diversion Capacity at Elevation15,155 cfs into All American Canal headworks 2,200 cfs into Gila Gravity Main Canal headworks 31,000 cfs to 42,500 cfs into sluiceway
Drainage Area
Hydrometeorological Report (HMR)HMR 36
Probable Maximum Flood (PMF) Report

Contact Information
TitleArea Office Manager
OrganizationYuma Area Office
Address7301 Calle Agua Salada
CityYuma, AZ 85364
Phone (Office)928 343-8100
OrganizationImperial Irrigation District
AddressPO Box 937
CityImperial, CA 92251
Phone (Office)760 482-9600

Last updated: Nov 16, 2009