Los Angeles River Watershed

It’s quite a mystery that we are so dependent on water from Owens Valley when we have a river in our backyard that we channelized to get rid of water from our streets.  In 1938, Los Angeles was going through some devastating floods and the US Army Corps of Engineers used 3.5 million barrels of concrete and 30 years to contain and redirect what is now the Los Angeles River Watershed. The entire length of the watershed is a total 51 miles with 32 miles running within the city of Los Angeles. It’s 870 sq. miles from the eastern portions of Santa Monica Mountains, and Simi Hills, and Santa Susana Mountains to the San Gabriel Mountains in the west. At peak times the river carries out 183,000 cubic feet of water per second out to the Pacific Ocean, that’s roughly over 10.8 million gallons per minute. Compare that to 430 million gallons that the LA Aqueducts provide per day.

Along with channelization of the river, habitats and wildlife have vanished. The Los Angeles River made the list of the country’s 20 most threatened and endangered rivers 6 times in the 1990’s and in 1995 it was named the second most endangered river in United States. The Los Angeles River has also been correlated with the contamination of Long Beach City beaches. During heavy rain all the trash that accumulates in the river ends up in the beaches.


Mouth of the Los Angeles River, Long Beach, California
Photo: Bill McDonald, Algalita Foundation

The Los Angeles River has become a dumping site and at the same time we have lost a valuable resource. It would also not be feasible for the city to use every drop of water that goes in the Los Angeles River. However, there is a balance that can be achieved by limiting runoff of water and using rainwater on site.


2 responses to “Los Angeles River Watershed

  1. I have come to believe that the Los Angeles Watershed is one of the best ways to waste water in Southern California. The water that just spills in the ocean could be used by the city but the decisions made in the past seem to grapple at the future. With the dwindling water supply the city should start looking at the destruction and reconstruction of the Los Angeles river.

  2. I strongly agree naisap’s comment about the LA Watershed is one of the best ways to waste water In fact,, because of the LA Aqueduct, many of habitat got disruption and many species loss their home.

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