Redd site selection and spawning habitat use by fall chinook salmon: The importance of geomorphic features in large rivers
- Pacific Northwest National Lab., Richland, WA (United States). Ecology Group
Knowledge of the three-dimensional connectivity between rivers and groundwater within the hyporheic zone can be used to improve the definition of fall chinook salmon (Oncorhynchus tshawytscha) spawning habitat. Information exists on the microhabitat characteristics that define suitable salmon spawning habitat. However, traditional spawning habitat models that use these characteristics to predict available spawning habitat are restricted because they can not account for the heterogeneous nature of rivers. The authors present a conceptual spawning habitat model for fall chinook salmon that describes how geomorphic features of river channels create hydraulic processes, including hyporheic flows, that influence where salmon spawn in unconstrained reaches of large mainstem alluvial rivers. Two case studies based on empirical data from fall chinook salmon spawning areas in the Hanford Reach of the Columbia River are presented to illustrate important aspects of the conceptual model. The authors suggest that traditional habitat models and the conceptual model be combined to predict the limits of suitable fall chinook salmon spawning habitat. This approach can incorporate quantitative measures of river channel morphology, including general descriptors of geomorphic features at different spatial scales, in order to understand the processes influencing redd site selection and spawning habitat use. This information is needed in order to protect existing salmon spawning habitat in large rivers, as well as to recover habitat already lost.
- Sponsoring Organization:
- USDOE Bonneville Power Administration, Portland, OR (United States)
- DOE Contract Number:
- AC06-76RL01830
- OSTI ID:
- 655410
- Journal Information:
- Environmental Management, Vol. 22, Issue 5; Other Information: PBD: Sep-Oct 1998
- Country of Publication:
- United States
- Language:
- English
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