Controls on Salmon and Lamprey Habitat along the Siletz River

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Chinook Salmon and Pacific Lamprey are culturally significant fishes to the Tribal community along the Siletz River, Oregon. The USGS has begun studying how streamflow and bedload conditions may influence mainstem spawning habitats.

Background

siletz basin

Map of the study area on the Siletz River, including proposed USGS study analysis domains and previous study area covered by the Bureau of Reclamation (BoR).

The study will be an important step forward to providing the Confederated Tribes of the Siletz Indians (Tribe) with a comprehensive and interdisciplinary assessment of present and future habitat conditions for culturally significant Chinook Salmon and Pacific Lamprey in the Siletz River basin. It will provide insight into the large-scale factors influencing channel stability as well as the influences of streamflow and bedload transport on mainstem spawning habitats for these fishes and the potential stability of these habitats with projected future streamflow conditions. The study brings together the hydrology and geomorphic expertise of the USGS Oregon Water Science Center and fish biology expertise from USGS Forest and Rangeland Ecosystem Science Center.

 

Objectives

The main objectives for this study include:

  1. Evaluating channel stability and bed-material transport on the Siletz River from Elk Creek to its mouth with a comparison of channel features mapped from 1939 and 2016 aerial photographs
  2. Assessing the controls on Chinook Salmon and Pacific Lamprey spawning habitats for a range of streamflow conditions using hydraulic and bedload transport models for the Siletz River from Wildcat Creek downstream to the town of Siletz and spawning data collected by the Tribe.

Findings from this study will support the Tribe, as well as partner organizations, as they develop management and habitat restoration strategies to protect and sustain culturally significant food resources and Tribal culture now and into the future. For instance, this would help the Tribe prioritize the locations of habitat conservation and restoration actions and anticipate how rivers and important spawning habitats in their management area may change in the coming decades.   

siletz bathymetry

USGS staff collecting bathymetry data to support the hydraulic model development.

(Credit: James White, USGS)