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North Bay steelhead: the historical record andimplications for restoration Gordon Becker, Senior Scientist Center for Ecosystem Management and Restoration (CEMAR)
Outline • The fish. Quick review of steelhead (Oncorhynchus mykiss) • Historical distribution/current status. Collecting, analyzing, and presenting fisheries information for Bay Area streams • San Francisco Estuary Watersheds Evaluation. An intuitive, rapid technique to identify and guide restoration activities • Steelhead passage and habitat projects. Developing “right fit” solutions in a “quick fix” world • Big picture. Current limitations of the steelhead recovery process and the “Big 3” problems/opportunities
Key traits of steelhead • Two forms. Steelhead are anadromous, or ocean going; resident rainbow trout can have a stream-only life cycle. • Iteropary. Some SH spawn in more than year (kelts). • Swimming performance. Power allows headwaters access. • Environmental tolerance. Adapted to mediterranean climate, thus largest range of the salmonids. • Plasticity. Depending on environmental conditions, steelhead can vary run and rearing in space and time.
Estuarine rearing Specific growth in the estuary was significantly greater than upstream habitats for 2003 and 2004 (t(501)=22.7, p<0.001, Figure 7 ). Mean growth in the estuary for 2003 and 2004 was 0.36% increase in FL per day, while mean upstream growth was 0.06% increase in FL per day for the same period. [Data from Scott Creek, Santa Cruz County] Bond, M.H. 2006. Importance of estuarine rearing to central California steelhead (Onocorhynchus mykiss) growth and marine survival. Master of Arts thesis, University of California Santa Cruz.
Steelhead distribution study goals • Provide authoritative Oncorhynchus mykiss information resource • Expand O. mykiss historical distribution and current status record • Contribute to O. mykiss conservation and recovery planning
Steelhead distributionstudy approach • Comprehensive information • Report for broad audience: text, tables, maps (and database in newer projects) • Transparent process of data mining • Peer review
Estuary streams report results • Coho. Nine historical runs; now extirpated from region. • Chinook. Nine streams with possible historical runs; now at least six streams with recurring runs. • Steelhead/rainbow trout. 194 streams with historical definite use; now 134 (69 percent) streams with definite runs or populations. • Oncorhynchus mykiss abundance. Reliable evidence of population decline in 158 streams (81 percent). • O. mykiss anadromy. Anadromous life history possible in 19 watersheds (53 percent of historical SH watersheds) and 67 streams (35 percent of historical SH streams).
Marin County findings • Arroyo Corte Madera del Presidio and Corte Madera Creek both productive, both heavily channelized • San Anselmo Creek highest productivity in Corte Madera Creek watershed
Sonoma County findings • Estimated run of 500 in 1965 • Best productivity likely in Carriger Creek and upper mainstem and headwaters tributaries (e.g., Stuart Creek)
Napa County findings • Napa River system most important Bay Area steelhead resource: historical 6K to 8K average?; 1,200-1,300 in 1969? • Best productivity in west-side tributaries like Redwood, Dry, and Sulphur creeks
Solano County findings • Likely substantial Suisun Creek run until construction of Gordon Valley Dam (Lake Curry) in 1926 • History of calls for instream flow protection on Wooden Valley Creek
North Bay findings • O. mykiss remains in higher percentage of No. Bay streams than Bay average • Streams supporting anadromous life history populations greatly reduced • Population decline in all streams • Many reproducing isolated populations (i.e., run refreshing genome decreased)
Data findings • Sampling, effort and information sharing problems limit O. mykiss understanding • Number of surveys per stream low • Recent (≤ ten years) information lacking • Population features (e.g., density, year classes, abundance) rarely estimated; habitat characterizations unusable
Anchor Watersheds Rationale • Steelhead/rainbow trout populations. Reproduction indicates functioning habitat. • Substantial available habitat. Considered at a screening level, the rearing habitat accessible in a watershed restored through highly likely actions. • Passage barrier programs. Barriers identified and subject of engineered designs to modify or remove them. • Collaborative restoration planning. Watershed has a regulatory or stakeholder process to “drive” restoration. • Land use controls. This criterion reflects the importance of watershed areas in public ownership or otherwise protected from adverse land use effects.
Next steps Limiting factors reviews lead to: Instream flow provisions. Reservoir releases or minimum flows based on availability study. Passage barrier modifications. Design informed by hydrologic/geomorphic principles. Land use improvements. Ideal of dedicated stream corridor and effective erosion control.
Stuart Ck, Sonoma Creek watershed
Ritchey Creek, Napa River watershed
Fish passage design • Optimize passage using migration season 95 percent and 2 percent exceedence flows • “Design” high flow at 10 percent annual exceedence (i.e., low end of in-migration flow) • Minimum depth 0.8 feet for short reach only!!! • Natural fishway over low flow (e.g., Denil)
Generalized watershed-level restoration planning • Stakeholder process critical • Action Plan of necessary restorations • High quality information speeds progress • Extra planning, extra $ for best designs
North Bay big picture issues • Land too valuable for riparian use • Seasonal supply/demand dichotomy • Land in private ownership • Last hope for region
Even bigger picture issues • Science to policy work needed (e.g., re: barriers, hatcheries, ESUs) • Without water conservation, growth remains the 800 pound gorilla • Structural problems inhibit water and land use decision-making regarding steelhead • Ultimately, all restoration is local
“Big 3” - #1, Barriers • Flood works and road crossings in lower watershed, downstream from habitat - cost of right-of-way and free-span • Dry season diversions strand and inhibit summer movement - long standing tradition with potentially costly fix • Major water supply features without fishways downstream from habitat - efficiency of large or low-flow ladders
Barrier solutions • Design fishways and channels to modern hydrograph • Free-span • Consider re-connecting up- and down- stream populations (e.g., trap+truck) • Monitored off-stream storage
“Big 3” - #2, Sediment • “Non-point” - access and coverage issues • Jurisdiction/enforcement - “take” case hard; missing prosecutors • Disregard/lack of understanding - poor logging, grading, encroachment practices • Riparian area policy - Setbacks not enforced; revisions unsuccessful
Sediment solutions • Re-establish riverine access • RWQCB process • Steelhead stream campaign • Achieve setback consensus
“Big 3” - #3, Water • Instantaneous/annual over-appropriation: diversion (allowable + illegal) ≥ supply • Balance data - supply and demand information inaccurate and incomplete • Groundwater - unregulated; hard to show “take” • Fish flows - methods for setting rearing and migration flows sub-standard
Water solutions • Water budget for critical streams • Metering and seasonal diversion control • Biologically based in-stream flows • Groundwater and illegal diversion management program • Make pigs fly