Tujunga Wash — San Gabriel Mountains tributary to the Los Angeles River

Course and main components

Tujunga Wash begins as two principal forks. Big Tujunga Creek originates high in the San Gabriel Mountains and is impounded upstream to form the Big Tujunga Reservoir. Downstream of the dam the stream is commonly referred to as Big Tujunga Wash. Little Tujunga Creek drains an adjacent portion of the mountains to the north of Hansen Reservoir and flows south to join the larger branch. The combined flow enters Hansen Reservoir, which moderates floods and releases flows into the engineered wash channel that trends south toward the Los Angeles River.

Infrastructure and flood control

The lower reaches of Tujunga Wash include concrete-lined channels, levees and several impoundments built to reduce flood risk and store water where possible. The dams and reservoirs in the watershed were constructed in the 20th century as part of a broader effort to control seasonal floods that could otherwise inundate communities on the basin floor. Downstream improvements also facilitate conveyance through densely developed areas and reduce the hazard posed by intense, mountain-derived storms. Local recreation and water-management facilities are often co-located with these flood-control projects; for example, the Hansen area combines storage with open-space and parkland.

Ecology, environmental concerns and management

Although large stretches of Tujunga Wash have been channelized, remaining riparian patches and upstream mountain canyons support native vegetation and wildlife typical of Southern California streams. Urban runoff, altered sediment regimes and periodic high flows from storms affect water quality and habitat continuity. In recent decades, agencies and community groups have advocated for selective habitat restoration, improved water quality practices and designs that balance flood protection with ecological function.

Recreation, access and cultural history

Parts of the Tujunga watershed offer trails, picnic areas and limited recreation near reservoirs and downstream parks. The wash flows through areas that were historically occupied by indigenous peoples of the Los Angeles Basin, including the Tongva, and later shaped by ranching, urban growth and modern infrastructure. Visitors are commonly advised to respect posted closures and to be alert for sudden flows during or after mountain storms.

Key facts and notable features

• Watershed area: about 225 square miles (≈580 km²).
• Primary forks: Big Tujunga Creek and Little Tujunga Creek.
• Reservoirs and dams moderate floods; one notable impoundment is Big Tujunga Reservoir and another is the Hansen storage area managed for flood control and recreation.
• Meets the Los Angeles River near Studio City after receiving tributaries such as Pacoima Wash.
• Contributes roughly one fifth of the Los Angeles River flow in many years and remains a focus of flood-control, habitat and urban-water projects.

For maps, flood-history records and agency plans related to watershed management and recreation, consult local flood control and parks authorities as well as regional resources that document the wash's role in Los Angeles County water systems. Additional technical and historical references are available through municipal and federal agencies involved with the basin's infrastructure and conservation efforts; specific project pages and reports provide detail on structures such as the dam at the west shore of the Big Tujunga impoundment.