Skip Links

USGS - science for a changing world

Open-File Report 2011–1230

Prepared in cooperation with the U.S. Army Corps of Engineers

A Multi-Year Analysis of Passage and Survival at McNary Dam, 2004–09

By Noah S. Adams, Christopher E. Walker, and Russell W. Perry

Thumbnail of and link to report PDF (4.7 MB)Abstract

We analyzed 6 years (2004–09) of passage and survival data collected at McNary Dam to determine how dam operations and environmental conditions affect passage and survival of juvenile salmonids. A multinomial logistic regression was used to examine how environmental variables and dam operations relate to passage behavior of juvenile salmonids at McNary Dam. We used the Cormack-Jolly-Seber release-recapture model to determine how the survival of juvenile salmonids passing through McNary Dam relates to environmental variables and dam operations. Total project discharge and the proportion of flow passing the spillway typically had a positive effect on survival for all species and routes. As the proportion of water through the spillway increased, the number of fish passing the spillway increased, as did overall survival. Additionally, survival generally was higher at night. There was no meaningful difference in survival for fish that passed through the north or south portions of the spillway or powerhouse. Similarly, there was no difference in survival for fish released in the north, middle, or south portions of the tailrace. For subyearling Chinook salmon migrating during the summer season, increased temperatures had a drastic effect on passage and survival. As temperature increased, survival of subyearling Chinook salmon decreased through all passage routes and the number of fish that passed through the turbines increased. During years when the temporary spillway weirs (TSWs) were installed, passage through the spillway increased for spring migrants. However, due to the changes made in the location of the TSW between years and the potential effect of other confounding environmental conditions, it is not certain if the increase in spillway passage was due solely to the presence of the TSWs. The TSWs appeared to improve forebay survival during years when they were operated.

First posted September 7, 2011

For additional information contact:
Director, Western Fisheries Research Center
U.S. Geological Survey
6505 NE 65th Street
Seattle, Washington 98115
http://wfrc.usgs.gov/

Part or all of this report is presented in Portable Document Format (PDF); the latest version of Adobe Reader or similar software is required to view it. Download the latest version of Adobe Reader, free of charge.


Suggested citation:

Adams, N.S., Walker, C.E, and Perry, R.W., 2011, A multi-year analysis of passage and survival at McNary Dam, 2004–09: U.S. Geological Survey Open-File Report 2011-1230, 128 p.



Contents

Abstract

Introduction

Description of Study Area

Methods

Results

Discussion

References Cited

Appendix A: Weekly Survival Estimates


Accessibility FOIA Privacy Policies and Notices

USA.gov logo U.S. Department of the Interior | U.S. Geological Survey
URL: https://pubs.usgs.gov/of/2011/1230/
Page Contact Information: Contact USGS
Page Last Modified: Wednesday, December 07, 2016, 11:55:10 PM