Purpose: To evaluate restoration of the aquatic and riparian habitat along Malibu Creek, specifically, the area along the mainstream of Malibu Creek below Malibu Dam and several tributaries to Malibu Creek. Habitat connectivity in lower Malibu Creek is blocked by Rindge Dam. Restoration of natural sediment transport to nourish coastal environments is the other key component of the study. Addressing Rindge Dam is the key to aquatic ecosystem restoration and natural sediment transport regimes within this watershed. Rindge Dam is the focus particularly to restore quality spawning and rearing habitat for the endangered steelhead trout and other sensitive species.
Study Area: Malibu Creek is located approximately 30 miles west of downtown Los Angeles, California. Approximately two-thirds of the watershed is located in northwestern Los Angeles County and the remaining one-third is in southeastern Ventura County. The drainage area covers approximately 110 square miles of the Santa Monica Mountains and Simi Hills. Elevations in the watershed range from over 3,100 ft at Sandstone Peak in Ventura County to sea level at Santa Monica Bay.
Problem Summary: The study has identified four key problem areas.
1. Rindge Dam and other upstream barriers block migratory species, isolating reaches of Malibu Creek and tributaries in the watershed and obstructing access to former spawning and rearing habitat.
2. The natural sediment regime on Malibu Creek has been disrupted by Rindge Dam since the construction of several water supply and recreational dams in the watershed.
3. Water quality in the Malibu Creek watershed is degraded due to Rindge Dam and urbanization impacts within the watershed.
4. Downstream reaches of Malibu Creek have changed from seasonal (ephemeral) flows to year-round (seasonal) flows, altering the aquatic and riverine habitat present in lower Malibu Creek.
Study Participants: The lead federal agency for this study is the US Army Corps of Engineers, Los Angeles District, in coordination with the non-Federal study Sponsor, the State of California, Department of Parks and Recreation. Multiple other agencies have and continue to contribute to this study effort.