| Imperial Dam | |
|---|---|
 | |
  Location of Imperial Dam in the United States  Imperial Dam (Arizona) | |
| Official name | Imperial Diversion Dam |
| Location | Lower Colorado River Valley Imperial County, California Yuma County, Arizona |
| Coordinates | 32°52′59″N 114°27′54″W / 32.883°N 114.465°W |
| Construction began | 1936 |
| Opening date | 1938 |
| Owner(s) | United States Bureau of Reclamation |
| Operator(s) | Imperial Irrigation District |
| Dam and spillways | |
| Impounds | Colorado River |
| Height | 85 ft (26 m) |
| Length | 3,475 ft (1,059 m) |
| Width (base) | 76 ft (23 m) |
| Reservoir | |
| Creates | Imperial Reservoir |
| Total capacity | 160,000 acre⋅ft (200,000,000 m3) (now silted) |
| Surface area | 5,756 acres (2,329 ha) |
The Imperial Diversion Dam (National ID # CA10159) is a concrete slab and buttress, ogee weir structure across the California/Arizona border, 18 miles (29 km) northeast of Yuma. Completed in 1938, the dam retains the waters of the Colorado River into the Imperial Reservoir before desilting and diversion into the All-American Canal and the Gila Project aqueduct. Between 1932 and 1940, the Imperial Irrigation District (IID) relied on the Inter-California Canal and the Imperial Canal and Alamo River.