<P> An additional system diverts water from the Colorado River at the Imperial Diversion Dam provides waters to the Imperial and Coachella valleys as well as Yuma, Arizona, via the Alamo Canal, the Coachella Canal and the All - American Canal, which runs alongside the Mexican border . This system was also responsible for the accidental re-creation of the Salton Sea in 1905 . </P> <P> The Colorado is considered over-allocated, because apportionments were made on inaccurate measurements of annual runoff . Marc Reisner in Cadillac Desert noted that the Colorado is "unable to satisfy all the demands on it, so it is referred to as a' deficit' river, as if the river were somehow at fault for its overuse". For years California took more than its share of the apportionment, because other states were not prepared to use their entire allotments . MWD became used to 800,000 acre feet (0.99 km) excess of water . Pressure from other Colorado river states caused the Secretary of the Interior to order California to show progress towards decreasing its dependency on the excess 800,000 acre feet (0.99 km), or face cuts . The Colorado River Water Use Plan called for Imperial and Coachella Valley agriculture to give up water in order to reallocate 800,000 acre feet (0.99 km) within the state . The plan's proposals generated much controversy, and the deadline arrived with no agreement reached . The Department of the Interior reduced MWD's access by 415,000 acre feet (0.512 km). </P> <P> The Los Angeles Aqueduct carries water from the Eastern Sierra Nevada to Los Angeles . The construction of the aqueduct marked the first major water delivery project in California . The city purchased 300,000 acres (1,200 km) of land in the Owens Valley in order to gain access to water rights . The Los Angeles Department of Water and Power transports 400,000 acre feet (0.49 km) of Eastern Sierra Nevada water to the city each year . This growth clearly shows William Mulholland's observation that "Whoever brings the water, brings the people ." </P> <P> After four decades of diversion from the Mono Lake area, environmental damage created an environmental battle in the 1980s, with a victory for the Mono Lake proponents in 1994 . Other problems arose when dust from the bed of Owens Lake (completely dried up by diversions) became a major source of air pollution in the southern Owens Valley . To restore Mono Lake, correct air - quality law violations, and rewater portions of the Owens River, Los Angeles has begun to reduce its dependence on Eastern Sierra Nevada water . This has mostly been achieved through water conservation . The city enacted a program offering free low - flow toilets to its customers . </P>

Where does the water in los angeles come from