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Water temperature effects from simulated changes to dam operations and structures in the Middle and South Santiam Rivers, Oregon

Open-File Report 2017-1063
Prepared in cooperation with the U.S. Army Corps of Engineers, Portland District
By:
https://doi.org/10.3133/ofr20171063

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Abstract

Green Peter and Foster Dams on the Middle and South Santiam Rivers, Oregon, have altered the annual downstream water temperature profile (cycle). Operation of the dams has resulted in cooler summer releases and warmer autumn releases relative to pre-dam conditions, and that alteration can hinder recovery of various life stages of threatened spring-run Chinook salmon (Oncorhyncus tshawytscha) and winter steelhead (O. mykiss). Lake level management and the use of multiple outlets from varying depths at the dams can enable the maintenance of a temperature regime more closely resembling that in which the fish evolved by releasing warm surface water during summer and cooler, deeper water in the autumn. At Green Peter and Foster Dams, the outlet configuration is such that temperature control is often limited by hydropower production at the dams. Previously calibrated CE-QUAL-W2 water temperature models of Green Peter and Foster Lakes were used to simulate the downstream thermal effects from hypothetical structures and modified operations at the dams. Scenarios with no minimum power production requirements allowed some releases through shallower and deeper outlets (summer and autumn) to achieve better temperature control throughout the year and less year-to-year variability in autumn release temperatures. Scenarios including a hypothetical outlet floating 1 meter below the lake surface resulted in greater ability to release warm water during summer compared to existing structures. Later in Autumn (October 15–December 31), a limited amount of temperature control was realized downstream from Foster Dam by scenarios limited to operational changes with existing structures, resulting in 15-day averages within 1.0 degree Celsius of current operations.

Suggested Citation

Buccola, N.L., 2017, Water temperature effects from simulated changes to dam operations and structures in the Middle and South Santiam Rivers, Oregon: U.S. Geological Survey Open-File Report 2017–1063, 19 p., https://doi.org/10.3133/ofr20171063.

ISSN: 2331-1258 (online)

Study Area

Table of Contents

  • Abstract
  • Introduction
  • Purpose and Scope
  • Study Area
  • Methods and Data
  • Results and Discussion
  • Summary and Conclusions
  • Acknowledgments
  • Supplemental Materials
  • References Cited
Publication type Report
Publication Subtype USGS Numbered Series
Title Water temperature effects from simulated changes to dam operations and structures in the Middle and South Santiam Rivers, Oregon
Series title Open-File Report
Series number 2017-1063
DOI 10.3133/ofr20171063
Year Published 2017
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) Oregon Water Science Center
Description vi, 19 p.
Country United States
State Oregon
Other Geospatial Santiam River Basin
Online Only (Y/N) Y
Google Analytic Metrics Metrics page
Additional publication details