Watersheds in Los Angeles and Ventura Counties
Los Angeles County Dominant Watersheds
- Los Angeles River Watershed: (The one we are focusing on!) A massive and highly urbanized watershed, but with significant natural headwaters in the mountains.
- San Gabriel River Watershed: Flows through the eastern part of the county, starting in the San Gabriel Mountains.
- Ballona Creek Watershed: A highly urbanized watershed draining a large part of the westside of LA, including Culver City and Santa Monica.
- Dominguez Channel and Los Angeles Harbor Watershed: A heavily industrialized watershed in the south, flowing into the Ports of LA and Long Beach.
- North Santa Monica Bay Watershed: This area is generally comprised of the
- Malibu Creek Watershed and Topanga Creek Watershed—more rural and characterized by the Santa Monica Mountains.
Ventura County Dominant Watersheds
- Santa Clara River Watershed: One of the largest and most natural river systems remaining in Southern California. About 40% of it is in Los Angeles County and 60% in Ventura County.
- Ventura River Watershed: The smallest of Ventura County's majors, known for relying entirely on local water supplies.
- Calleguas Creek Watershed: Covers the southeastern part of Ventura County, including Simi Valley and Thousand Oaks, draining into Mugu Lagoon.