Not much of the water in Los Angeles comes from local sources—most of it is brought from hundreds of miles away. Large aqueducts, man-made channels used to transport water, were built to carry water from Owens Valley (in East-Central California), from the Colorado River, and from the rivers of Northern California, to Los Angeles. Though this method has brought fresh water to a region that desperately needs it, it has also drained and damaged the ecologies that once depended on the water now being sapped from its supply.