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Napa Valley Watershed Resources Analysis and Steelhead Growth Project
The Napa River drains a 426-mi2 watershed, with approximately 1,400 miles of streams. Watershed-wide changes, largely resulting from urban and agricultural development, have created potential conflicts between natural resource conditions and uses (e.g., sediment load, flood management, water supply, and aquatic habitat conditions). Steelhead in the Napa River watershed have exhibited substantial declines in abundance since the 1960s. Elevated levels of fine sediment and high water temperatures have likely reduced aquatic habitat quality in the watershed, but recent research indicates that these factors were not the primary mechanisms responsible for the decline of steelhead. Although multiple factors may have contributed to the decline, the most likely hypothesis is that flow reductions in key rearing streams have reduced food availability for juvenile steelhead, causing reduced growth and survival (Stillwater Sciences and Dietrich 2002).
Through focused scientific research and data collection, the Napa Valley Watershed Resources Analysis Project is intended to identify the connection between public resource policy and private land management and stewardship activities, and to support the development of specific priorities for the management and enhancement of fish and aquatic wildlife habitat in the Napa River watershed.
The information generated by the research, monitoring, and modeling will be synthesized with other information in a spatially registered watershed model and a final watershed analysis report. The model and report will provide the compilation and analysis of reliable and verifiable scientific data necessary to inform restoration projects, local policy decisions, stewardship activities, funding opportunities, land management decisions, long term monitoring, and public education and involvement.
A total of 14 tasks have been identified and will be developed as independent work products, enabling individual tasks to be completed as US Army Corps of Engineers (USACE) and project partner funds become available. Collection of external data may include, but will not be limited to, previous studies, ongoing monitoring, published literature, unpublished reports, and communications with local experts. In addition to the primary sources identified above, queries of appropriate databases will also be conducted to identify additional sources of information.
New data will be collected primarily through field surveys. Field surveys may include: instream woody debris surveys, surveys of California freshwater shrimp abundance and habitat, mapping of geomorphic features and habitat for aquatic and riparian species, air and water temperature data collection, vegetative cover inventory (field surveys and analysis of historical photographs), macroinvertebrate sampling, fish surveys consisting of electrofishing (to determine abundance and monitor bioenergetics), weir trapping, mapping of fish barriers and adult spawning habitat, redd surveys, and stomach sampling to determine diet composition. Additional information and detail on the individual tasks and methods used for sampling will be available in the work plan for each task.
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Tasks - Funded and In Progress
- Baseline Task 1 – Data Evaluation and Outreach
- Task Option 10 – Steelhead Bioenergetics Analyses
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Other Tasks (Funding not yet authorized)
- Task Option 2 – Physical Barriers to Fish Passage
- Task Option 3 – Aquatic Habitat, Floodplain Complexity and Large Woody Debris Dynamics
- Task Option 4 – California Freshwater Shrimp Research
- Task Option 5 – Stream Temperatures
- Task Option 6 – Map Current and Historical Channel Geomorphology and Habitat Conditions
- Task Option 7 – Historical Salmonid Distribution and Abundance
- Task Option 8 – Salmonid Migration Monitoring
- Task Option 9 – Predator Sampling
- Task Option 11 – RWQCB Sediment Dynamics Evaluation
- Task Option 12 – Napa Valley Watershed Dynamics Analysis Model
- Task Option 13 – Napa Valley Watershed Scorecard
- Task Option 14 – Final Napa Valley Watershed Management Report
For more information on this project please contact us.
Contact Information:
Stillwater Sciences
2855 Telegraph Ave, Suite 400
Berkeley, CA 94705
Phone: 510.848.8098, Fax: 510.848.8398
www.stillwatersci.com
