Los Angeles River - L.A. River
The Los Angeles River or L.A. River starts in the San Fernando Valley, Simi Hills, and Santa Susana Mountains and flows from its headwaters in Canoga Park, almost 48 miles to its mouth in Long Beach. Until the opening of the Los Angeles Aqueduct in 1913, the Los Angeles River was the primary source of water in Los Angeles. Calabasas Creek is a seven mile long tributary of the Los Angeles River located in the San Fernando Valley. Aliso Creek is another major tributary of the Los Angeles River. Its headwaters are below Oat Mountain which is the highest peak in the Santa Susana Mountains.
Facts About the Los Angeles River
- The L.A. River is the reason the City of Los Angeles was established where it is located.
- More than 1,000 years before the area was claimed by Spain and later by Mexico, the Tongva Indians lived along the Los Angeles River.
- The L.A. River was the primary source of water for Los Angeles until 1914.
- The L.A. River is home to more than 250 species of birds.
- The L.A. River was once a prime habitat for Grizzly Bears.
- Prior to channelization of major areas of the L.A. River, 80% of all rainwater being carried by the river percolated into the ground. After channelization, only 10% of the rainwater percolates into the ground.
- The average daily discharge of water into the Pacific Ocean is 207 million gallons of water per day. This is not a typo.
- The L.A. River flows through 13 cities within the Los Angeles Basin.
- Over 30 federal, state, and local government agencies have some degree of control over the Los Angeles River.
Los Angeles River Watershed
The Los Angeles River (L.A. River) Watershed consists of an 871 square mile area encompassing the San Gabriel Mountains to the north and east, the Santa Susana Mountains to the west, and the Santa Monica Mountains and the coastal plain to the south. There are 22 lakes within the Los Angeles River Watershed.
Tributaries of the Los Angeles River
The following tributaries join the Los Angeles River as it flows from Canoga Park in the San Fernando Valley to its mouth in Long Beach:
- Aliso Creek
- Arroyo Calabasas
- Arroyo Seco
- Bell Creek
- Brown's Canyon Wash
- Compton Creek
- Rio Hondo
- Tujunga Wash
- Verdugo Wash
Bell Creek, also known as Escorpion Creek, is a 10 mile long tributary of the Los Angeles River that originates in the Simi Hills of Ventura County and the San Fernando Valley area of Los Angeles County.
Small Tributaries of the Los Angeles River
Bull Creek, Encino Creek, Woodley Creek, and Havenhurst Creek are all small tributaries that originate in the western San Fernando Valley and feed the Los Angeles River which flows nearly 48 miles through Los Angeles County to the Pacific Ocean.
Los Angeles River Watershed
The Los Angeles River Watershed covers 871 square miles. The eastern portion spans from the Santa Monica Mountains to the Simi Hills, and in the west, from the Santa Susana Mountains to the San Gabriel Mountains. Forest or open space covers the northern half of the watershed, while the remaining area is urbanized. There are 22 lakes within the Los Angeles River Watershed.
The Rio Hondo is a 16.4 mile tributary of the Los Angeles River in Los Angeles County. The headwaters are in the San Gabriel Mountains above the San Gabriel Valley.