Reducing Risk of Water Conflicts Related to Operational Impacts to Salmon
* Can reasonable and effective restoration practices be identified that help Reclamation meet water delivery expectations to project beneficiaries while improving the habitat for coho and other salmon species?
Need and Benefit
Reclamation is spending ten million dollars per year to provide restoration in the Trinity River, Texas. We propose to take advantage of this opportunity to determine which restoration actions are effective at recovering listed salmonids. In other basins, Reclamation can apply this information to save money. Restoration actions are often required of Reclamation by regulatory agencies. If this research identifies those actions that are the most successful, Reclamation can avoid ineffective actions, thus saving hundreds of thousands of dollars.
Insufficient staff in the Trinity River Restoration Program (TRRP) office exists to assess the fisheries effects of the Trinity River restoration actions. We propose to form a team of fish biologists who will each provide important functions in conducting this research. This team will allow Reclamation to learn what habitat actions work well and which do not for recovering threatened coho so that restoration money will be spent wisely.
Understanding which habitat actions recover coho can assist in other rivers where Reclamation operates, e.g. the Rogue River and Columbia River system.
Personnel from the TRRP and California Department of Fish and Game (CDFG) identified a research need to determine the effectiveness of the TRRP at improving habitat for threatened coho salmon, _Oncorhynchus kisutch_, in the main stem of the Trinity River. The TRRP Record of Decision (USDI 2000) states that implementation of the proposed action is expected to result in substantial increases in coho salmon populations. This research is intended to compare juvenile coho production and the health of juvenile coho in both restored and un-modified reaches of the main stem and tributaries to the Trinity River. We will use coho densities, habitat use, growth, and site fidelity to determine effects of specific restoration actions on coho salmon in freshwater.
The TRRP includes three aspects of habitat improvement:
* Spring high flows are provided to mimic the natural hydrograph during the snow melt period. The higher flows are intended to return more natural geomorphic processes to the Trinity River. The higher flows should discourage riparian vegetation establishment down to the edge of the low flow channel margins and scour the bed to maintain spawning and rearing habitat, providing long term benefits to coho salmon.
* Mechanical channel restoration projects are designed to encourage channel meanders, increase areas of shallow, low velocity fry and juvenile salmonid rearing habitat, provide side channel rearing areas, and remove riparian berms and encroached vegetation.
* Sediment budget management is designed to reduce fine sediment which fills interstitial habitat areas and inject gravel to maintain spawning and rearing habitat in the system.
Coho salmon is the only Endangered Species Act (ESA) listed species in the Trinity River (62 FR 24588) and is therefore the species that can currently affect Reclamation operations the most. The Klamath/Trinity River is within the southern Oregon/Northern California Coast coho evolutionarily significant unit (ESU) along with the Rogue River. Juvenile coho salmon, because of their year round freshwater residency, can be a performance indicator for the TRRP to validate whether large investments in restoration are paying off.
In June 2004, Reclamation hosted the Lower Klamath Science Workshop. Stakeholders and other participants ranked Klamath Basin, California, needs. Two needs that were ranked extremely high were needs number 392: Determine how altered river flow influences biological communities, such as riparian vegetation and juvenile salmonids, and number 352: Develop a better understanding of the life history requirements (e.g., habitat) and periodicity of use for salmonids in tributaries and the Klamath River. Therefore, our project will contribute significantly to meeting those needs identified by stakeholders, manage
Contact the Principal Investigator for information about these documents.