Partnerships for Steelhead in Southern California

Now obsolete, the Matilija Dam will be removed and the riverine environment restored to pre-dam conditions, thereby allowing endangered steelhead access to historical spawning and rearing habitats in Matilija Creek.

Photo Credit: Mark Capelli

by Anthony P. Spina and Mark H. Capelli

The Ventura River watershed in southern California is designated as critical habitat for an endangered population of steelhead (Oncorhynchus mykiss). Eliminating threats to steelhead in this watershed, which has unique physical and biological characteristics, is crucial to conserving the listed population (Boughton et al. 2006). Although few of the fish remain, the prognosis for Ventura River steelhead is not entirely gloomy. Thanks to conservation partnerships, work to restore the fish and its essential habitat has begun.

Through the Endangered Species Act (ESA), the National Marine Fisheries Service (NMFS) is collaborating with the Army Corps of Engineers (Corps) on the Matilija Dam Ecosystem Restoration Project. Constructed in 1946 on Matilija Creek, a tributary of the Ventura River, Matilija Dam caused extensive fragmentation and loss of steelhead habitat. The new project intends to reverse the environmental damage by removing the obsolete 200-foot- (about 67-meter-) tall dam in 2010 and restoring the riverine environment to pre-dam conditions. These actions should increase steelhead habitat and numbers (Capelli 2004), reducing the likelihood of extinction. The ESA section 7 interagency consultation between NMFS and the Corps identified project modifications that should improve the project results.

The Robles Diversion Dam was constructed in 1958 on the mainstem of the Ventura River as part of a local watersupply project. Because the structure was constructed without any provision for fish passage, steelhead could not reach prime upstream spawning and rearing habitats that the species accessed prior to the construction of the diversion dam. Through section 7 interagency consultation provisions of the ESA, NMFS worked with the Bureau of Reclamation from 1999 to 2003. This subsequently led to construction of a fish-passage facility in 2004 and implementation of an operational streamflow regime shortly thereafter to provide passage of adult and juvenile steelhead around the diversion dam. Monitoring steelhead passage is a condition of the project and will provide valuable information about the status of this species in the Ventura River watershed.

The projects at Matilija Dam and Robles Diversion Dam restore steelhead access to a combined 40 miles (about 64 kilometers) of spawning and rearing habitats that have been unavailable to the species for over half a century. These projects will also begin addressing threats that have impaired the watershed- specific hydrologic and sediment regimes, which is critical to provide riverine habitat conditions and characteristics that are consistent with the life history and habitat requirements of steelhead and many other species on the river. Among other federally-listed species that would benefit from the projects are the California red-legged frog, southwestern willow fly catcher, least Bell’s vireo, and tidewater goby.

The Robles Diversion Dam and fish passage facilities on the mainstem Ventura River in early 2004.

Photo Credit: NOAA

Entities that are responsible for otherwise lawful activities, but which incidentally cause harm to steelhead, can benefit from partnering with NMFS on conservation actions for steelhead. For instance, activities causing incidental harm to steelhead can be brought into compliance with the ESA through either a section 10 permit (which must be accompanied by a conservation plan) or section 7 interagency consultation. Depending on the actual approach for undertaking a particular conservation effort, organizations or individuals may qualify to receive partial funding contributions from various sources, which can lessen financial commitments that may accompany planning and implementation of conservation actions. Perhaps more important is the satisfaction of undertaking conservation actions that contribute favorably to the survival and growth of endangered steelhead, potentially saving the species from extinction.

While the conservation partnerships undertaken in the Ventura River watershed are an important first step for restoring riverine habitat functions essential for steelhead survival and growth within southern California, additional conservation efforts are necessary to fully and effectively address the ongoing threats to this species. This is particularly true if the species is to be spared extinction. To this end, future NMFS priorities within the Ventura River mainstem and joining tributaries include partnering with entities to (1) balance water-management needs and properly functioning living space for juvenile steelhead, (2) return lost habitat to steelhead, and (3) remediate the effects of human-made structures on the migration of this endangered species.

References

Boughton, D. A., P. B. Adams, E. Anderson, C. Fusaro, E. Keller, E. Kelley, L. Lentsch, J. Nielsen, K. Perry, H. Regan, J. Smith, C. Swift, L. Thompson, and F. Watson. 2006. Steelhead of the south-central/southern California coast: population characterization for recovery planning. NOAA Technical Memorandum, NOAA-TM-NMFS-SWFSC-394.

Capelli, M. H. 2004. Removing Matilija Dam: opportunities and challenges for Ventura River restoration. Proceedings, U. S. Society on Dams, 24th USSDA Annual Meeting, March 29-April 2, 2004, St. Louis, MO.

Anthony P. Spina, steelhead ecologist and the leader of the south coast steelhead team, and Mark H. Capelli, recovery coordinator for southern and south-central California steelhead, are located in the NMFS Southwest Regional Office. They can be reached at anthony.spina@noaa.gov and mark.capelli@noaa.gov.