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.

Three giant desilting basins and seventy-two 770 ft (230 m) scrapers hold and desilt the water; the removed silt is carried away by six sludge-pipes running under the Colorado River that dump the sediment into the California sluiceway, which returns the silt to the Colorado River.

Diversions can top 40,000 cubic feet (1,100 m3) per second, roughly the volume of the Susquehanna River and more than 50 times the flow of the Rio Grande[citation needed].

The Gila project aqueduct branches off towards Arizona while the All-American canal branches southwards for 37 miles (60 km) before reaching its headworks on the California border and bends west towards the Imperial Valley.