North Bay steelhead:
the historical record and
implications 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.
Middle Fork Eel summer steelhead
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 distribution
study approach
• Comprehensive information
• Transparent process of data mining
• Report for broad audience: text, tables,
maps (and database in newer projects)
• 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).
O. mykiss of Marin County streams
Historical “DF”
18
Current “DF”
17
Current ”DF"/
historical "DF"
94 percent
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
O. mykiss of Sonoma County streams
Historical “DF”
27
Current “DF”
22
Current ”DF"/
historical "DF"
81 percent
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)
O. mykiss of Napa County streams
Historical “DF”
44
Current “DF”
36
Current ”DF"/
historical "DF"
82 percent
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
O. mykiss of Solano County streams
Historical “DF”
6
Current “DF”
4
Current ”DF"/
historical "DF"
67 percent
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
• Recent (≤ ten years) information lacking
• Number of surveys per stream low
• 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:
Passage barrier modifications. Design informed
by hydrologic/geomorphic principles.
Instream flow provisions. Reservoir releases or
minimum flows based on availability study.
Land use improvements. Ideal of dedicated
stream corridor and effective erosion control.
San Anselmo Ck, Corte
Madera Ck watershed
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
• High quality information speeds progress
• Action Plan of necessary restorations
• Extra planning, extra $ for best designs
North Bay big picture issues
• Land too valuable for riparian use
• Land in private ownership
• Seasonal supply/demand dichotomy
• Last hope for region
Even bigger picture issues
• Science to policy work needed (e.g., re:
barriers, hatcheries, ESUs)
• Structural problems inhibit water and land
use decision-making regarding steelhead
• Without water conservation, growth
remains the 800 pound gorilla
• 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
• Major water supply features without
fishways downstream from habitat efficiency of large or low-flow ladders
• Dry season diversions strand and inhibit
summer movement - long standing
tradition with potentially costly fix
Barrier solutions
• Design fishways and channels to modern
hydrograph
• Consider re-connecting up- and downstream populations (e.g., trap+truck)
• Free-span
• Monitored off-stream storage
“Big 3” - #2, Sediment
• “Non-point” - access and coverage issues
• Disregard/lack of understanding - poor
logging, grading, encroachment practices
• Jurisdiction/enforcement - “take” case
hard; missing prosecutors
• Riparian area policy - Setbacks not
enforced; revisions unsuccessful
Sediment solutions
• Re-establish riverine access
• Steelhead stream campaign
• RWQCB process
• Achieve setback consensus
“Big 3” - #3, Water
• Instantaneous/annual over-appropriation:
diversion (allowable + illegal) ≥ supply
• Groundwater - unregulated; hard to
show “take”
• Balance data - supply and demand
information inaccurate and incomplete
• Fish flows - methods for setting rearing
and migration flows sub-standard
Water solutions
• Water budget for critical streams
• Biologically based in-stream flows
• Metering and seasonal diversion control
• Groundwater and illegal diversion
management program
• Make pigs fly