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Title: Bedform morphology of salmon spawning areas in a large gravel-bed river

Abstract

While the importance of river channel morphology to salmon spawning habitat is increasingly recognized, quantitative measures of the relationships between channel morphology and habitat use are lacking. Such quantitative measures are necessary as management and regulatory agencies within the Pacific Northwestern region of the USA, and elsewhere, seek to quantify potential spawning habitat and develop recovery goals for declining salmon populations. The objective of this study was to determine if fall Chinook salmon (Oncorhynchus tshawytscha) spawning areas in the Snake River, Idaho, USA, were correlated with specific bed form types at the pool-riffle scale. A bed form differencing technique was used to objectively quantify the longitudinal riverbed profile into four distinct pool-riffle units that were independent of discharge. The vertical location of thalweg points within these units was quantified with a riffle proximity index. Chinook salmon spawning areas were mapped and correlated with the pool-riffle units through the use of cross-tabulation tables. The results indicate that 84% of fall Chinook salmon spawning areas were correlated with riffles (Chi-square=152.1, df=3, p<0.001), with 53% of those areas located on the upstream side of riffle crests. The majority of Snake River fall Chinook salmon spawning occurred at a vertical location within 80% ofmore » the nearest riffle crest elevation. The analyses of bed form morphology will assist regional fish mangers in quantifying existing and potential fall Chinook salmon spawning habitat, and will provide a quantitative framework for evaluating general ecological implications of channel morphology in large gravel-bed rivers.« less

Authors:
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
903242
Report Number(s):
PNWD-SA-7419
Journal ID: ISSN 0202-7224; GEMPEZ; TRN: US200719%%521
DOE Contract Number:
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Geomorphology, 86(3-4):529-536; Journal Volume: 86; Journal Issue: 3-4
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; SEA BED; HABITAT; GEOMORPHOLOGY; RIVERS; SALMON; channel morphology; Chinook salmon; river bed form

Citation Formats

Hanrahan, Timothy P. Bedform morphology of salmon spawning areas in a large gravel-bed river. United States: N. p., 2007. Web. doi:10.1016/j.geomorph.2006.09.017.
Hanrahan, Timothy P. Bedform morphology of salmon spawning areas in a large gravel-bed river. United States. doi:10.1016/j.geomorph.2006.09.017.
Hanrahan, Timothy P. Tue . "Bedform morphology of salmon spawning areas in a large gravel-bed river". United States. doi:10.1016/j.geomorph.2006.09.017.
@article{osti_903242,
title = {Bedform morphology of salmon spawning areas in a large gravel-bed river},
author = {Hanrahan, Timothy P.},
abstractNote = {While the importance of river channel morphology to salmon spawning habitat is increasingly recognized, quantitative measures of the relationships between channel morphology and habitat use are lacking. Such quantitative measures are necessary as management and regulatory agencies within the Pacific Northwestern region of the USA, and elsewhere, seek to quantify potential spawning habitat and develop recovery goals for declining salmon populations. The objective of this study was to determine if fall Chinook salmon (Oncorhynchus tshawytscha) spawning areas in the Snake River, Idaho, USA, were correlated with specific bed form types at the pool-riffle scale. A bed form differencing technique was used to objectively quantify the longitudinal riverbed profile into four distinct pool-riffle units that were independent of discharge. The vertical location of thalweg points within these units was quantified with a riffle proximity index. Chinook salmon spawning areas were mapped and correlated with the pool-riffle units through the use of cross-tabulation tables. The results indicate that 84% of fall Chinook salmon spawning areas were correlated with riffles (Chi-square=152.1, df=3, p<0.001), with 53% of those areas located on the upstream side of riffle crests. The majority of Snake River fall Chinook salmon spawning occurred at a vertical location within 80% of the nearest riffle crest elevation. The analyses of bed form morphology will assist regional fish mangers in quantifying existing and potential fall Chinook salmon spawning habitat, and will provide a quantitative framework for evaluating general ecological implications of channel morphology in large gravel-bed rivers.},
doi = {10.1016/j.geomorph.2006.09.017},
journal = {Geomorphology, 86(3-4):529-536},
number = 3-4,
volume = 86,
place = {United States},
year = {Tue May 01 00:00:00 EDT 2007},
month = {Tue May 01 00:00:00 EDT 2007}
}