1996

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EPA determined that Idaho's cold water biota and salmonid spawning temperature criteria were not protective of bull trout and disapproved the criteria in streams within the geographic range of bull trout.  EPA also disapproved of the temperature criteria for a segment of the Kootenai River between Bonners Ferry and Shorty's Island. 

Oregon finished a triennial review of its water quality standards and submitted them to EPA for approval.

The National Marine Fisheries Service (now called NOAA Fisheries) and U.S. Fish and Wildlife Service conducted an Endangered Species Act consultation on Oregon water quality standards. 

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In an effort to prevent federal rule promulgation, Idaho adopted a temporary rule that contained revised temperature criteria for bull trout and a segment of the Kootenai River. 

EPA determined there was insufficient scientific rationale for the temporary bull trout temperature criteria, disapproved that portion of the temporary rule, and proceeded with federal promulgation of bull trout temperature criteria.  (See 62 FR July 1997)

EPA provided a conditional approval of the temperature criteria for the Kootenai River segment of concern.

DEQ hired a contractor to examine the validity of the federal rule as it applies to juvenile bull trout.   

Review of Bull Trout Temperature Requirements: A Response to the EPA Bull Trout Temperature Rule

DEQ undertook an effort to examine the relationship between documented stream temperatures and salmonid populations in Idaho. This study found there were many instances where salmonid spawning has occurred coincidentally with measured temperature criteria exceedances. 

The Dilemma of Applying Uniform Temperature Criteria in a Diverse Environment: An Issue Analysis

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DEQ proposed a seasonal cold aquatic life use category and associated criteria. 

DEQ retained a contractor to evaluate the temperature requirements of fish species that would likely occur in waters classified as having a seasonal cold water aquatic life beneficial use. 

Evaluation of Seasonal Cold Water Temperature Criteria

DEQ became involved in a project to conduct aerial thermal infrared imaging of the lower Snake and Clearwater Rivers, below Hells Canyon and Dworshak Dams. This effort was made to examine downstream trends in water temperature, investigate the influence of tributaries, and identify possible cold water refugia for salmon.  

DEQ submitted the Lochsa River Subbasin Assessment to EPA.  In this assessment, DEQ concluded that stream temperatures in the Lochsa River and its tributaries were naturally high during the summer and early fall. DEQ recommended that the Lochsa River and Canyon Creek be removed from the §303(d) list. 

EPA disagreed with DEQ's conclusion that water temperatures in the Lochsa subbasin were natural. 

DEQ hired a consultant to conduct a water temperature modeling study in the Lochsa subbasin.  Results of the model indicated that natural disturbances were the dominant factor impacting water temperatures in the subbasin.  

Water Temperature of the Lochsa River and Selected Tributaries

EPA approved of Oregon's water quality standards. As part of that approval, Oregon was required to participate in a regional interagency effort to develop a guidance document for the development of temperature criteria.

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The seasonal cold aquatic life use category and associated criteria were adopted into Idaho water quality standards.  To date, EPA has not formally acted on this portion of Idaho's water quality standards.

Along with Oregon and Washington, Idaho began participating in an interagency effort to develop EPA Region 10 temperature criteria. 

DEQ hired a contractor to examine the distribution of summer water temperatures in the Clearwater and Owyhee drainages. 

Paired Color Infrared and Thermal Infrared Imaging and Analysis for Selected Idaho Streams, 2000 Report 

DEQ completed rulemaking that modified existing water quality standards that allows natural background conditions to supplant numeric criteria for toxic substances. The revision expanded the scope to include parameters other than toxics, such as dissolved oxygen and temperature.

Concepts and Recommendations for Using the "Natural Conditions" Provisions of the Idaho Water Quality Standards

The U.S. Geologic Survey (USGS) initiated a study (sponsored by DEQ) to develop a statistical model that can be used to estimate natural stream temperatures based on a variety of basin characteristics and other readily available data. 

A Statistical Model for Estimating Stream Temperatures in the Salmon and Clearwater River Basins, Central Idaho

DEQ conducted water quality monitoring of the Selway and Middle Fork Salmon Rivers to document baseline conditions for possible designation as "Outstanding Resource Waters." (The study continued in 2001.)  The data showed that even these pristine waters did not always meet Idaho's cold water criteria, providing further evidence that these criteria do not match reality.

Wilderness Water Temperatures:  A Look at the Selway and Middle Fork Salmon (This file is very large [5.6 mb] and may be difficult to download.  It has been divided into smaller pieces below for easier downloading)

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Northwest Environmental Advocates (NWEA) challenged EPA and NOAA Fisheries on the approval of Oregon's water quality standards. View summary.

DEQ hired a contractor to examine the distribution of summer water temperatures in the Salmon drainage.

Paired Color Infrared and Thermal Infrared Imaging and Analysis for Selected Idaho Streams, 2001 Report

USGS initiated a study (sponsored by DEQ) to examine the relationship between water temperature and distribution of aquatic assemblages.   

Aquatic Assemblages and Their Relation to Temperature Variables of Least-Disturbed Streams in the Salmon River Basin, Central Idaho, 2001

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DEQ initiated a pilot study on the Chiwawa River in north central Washington to examine the applicability of the draft Region 10 temperature guidance in a relatively pristine watershed.  Results indicated that while most of the recommended temperature criteria were met, there were exceedances of the recommended bull trout temperature criteria. 

Application of New Approaches to Water Quality Temperature Criteria:  Chiwawa River Case Study

At EPA's request, DEQ issued a dissenting opinion on the biological threshold numbers proposed by the regional temperature criteria development workgroup. 

Dissenting Opinion on Biological Threshold Numbers Proposed by Regional Temperature Criteria Development Technical Workgroup

Two draft Region 10 temperature guidance documents were released for public review. 

DEQ commented on the final proposed guidance, pointing out that EPA's proposed criteria failed to adequately allow for natural variability in water temperatures.

State of Idaho Comments on Second Public Review Draft of Proposed EPA Region 10 Guidance for Pacific Northwest State and Tribal Temperature Water Quality Standards

DEQ studied past literature to better understand historical temperatures and how they varied from year-to-year in the Pacific Northwest.  The data showed that temperatures higher than Idaho's current temperature criteria existed historically and that inter-annual variations in water temperatures of several degrees were common.

Year-to-Year Variation in Stream Temperature and Implications for Water Quality Criteria

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DEQ prepared a report to update bull trout temperature requirements.  This report concluded that a temperature criterion of 13 ºC expressed as a maximum weekly maximum temperature, would be fully protective of bull trout rearing during the months of June, July, and August.

Update of Bull Trout Temperature Requirements

DEQ promulgated a rule that allowed for the stream temperature criteria to be exceeded during unusually hot climatic conditions (the rule promulgation effort began in 2001).  To date, EPA has not acted on the rule.

The final version of the Region 10 temperature guidance was completed. 

EPA Region 10 Temperature Guidance

The court ruled in favor of NWEA and ordered EPA to promulgate temperature criteria for bull trout and salmonid rearing.  Prior to federal promulgation, Oregon adopted new temperature criteria based on the Region 10 temperature guidance, and EPA halted federal rulemaking.

DEQ completed a pilot application of the final Region 10 temperature guidance in the Lochsa River subbasin and found that none of the streams within the subbasin met the regionally recommended bull trout temperature criteria; however, the subbasin is considered to be a stronghold for bull trout populations.

Lochsa River Basin Temperature Guidance Pilot Project: Clearwater Subbasin

Application of New Approaches to Water Quality Temperature Criteria: Chiwawa River Case Study  (DEQ Publication, March 2002: pdf 1.5 mb, 54 pages)

Appendix A: Potential Salmonid Distributions in the Chiwawa River Basin  (pdf 1.4 mb, 64 pages)

Aquatic Assemblages and Their Relation to Temperature Variables of Least-Disturbed Streams in the Salmon River Basin, Central Idaho

(USGS Web Site: pdf 4.9 mb, 52 pages)

The Dilemma of Applying Uniform Temperature Criteria in a Diverse Environment: An Issue Analysis  (DEQ Publication, November 1998: pdf 198 kb, 34 pages)

Dissenting Opinion on Biological Threshold Numbers Proposed by Regional Temperature Criteria Development Technical Workgroup

(DEQ Publication, November 2002: pdf 192 kb, 24 pages)

Evaluation of Seasonal-Cold-Water Temperature Criteria

(DEQ Publication: pdf 134 kb, 50 pages)

Lochsa River Basin Temperature Guidance Pilot Project Clearwater Subbasin

(DEQ Publication, August 2005: pdf 788 kb, 20 pages)

Paired Color Infrared and Thermal Infrared Imaging and Analysis for Selected Idaho Streams, 2000 Report  (DEQ Publication, April 2001: pdf 4 mb, 40 pages)

Paired Color Infrared and Thermal Infrared Imaging and Analysis for Selected Idaho Streams, 2001 Report  (DEQ Publication, August 2002: pdf 1.3 mb, 27 pages)

State of Idaho Comments on Second Public Review Draft of Proposed EPA Region 10 Guidance for Pacific Northwest State and Tribal Temperature Water Quality Standards (DEQ Publication, November 2002: pdf 210 kb, 9 pages)

A Statistical Model for Estimating Stream Temperatures in the Salmon and Clearwater River Basins, Central Idaho (USGS Web Site: pdf 1.5 mb, 46 pages)

Update of Bull Trout Temperature Requirements 

(DEQ Publication, April 2003: pdf 695 kb, 48 pages)

Water Temperature of the Lochsa River and Selected Tributaries

(DEQ Publication, July 2002: pdf 2.2 mb, 55 pages)

Wilderness Water Temperatures:  A Look at the Selway and Middle Fork Salmon

(DEQ Presentation, 2002: pdf 5.6 mb, 50 pages)

Because of the large size of this pdf document, we have also divided it into sections for quicker download.

Wilderness Water Temperature (pgs 1 - 10) (pdf 1.5 mb, 10 pages)

Wilderness Water Temperature (pgs 11 - 20) (pdf 695 kb, 11 pages)

Wilderness Water Temperature (pgs 21 - 25) (pdf 1.6 mb, 6 pages)

Wilderness Water Temperature (pgs 26 - 30) (pdf 1.3 mb, 6 pages)

Wilderness Water Temperature (pgs 31 - 40) (pdf 252 kb, 11 pages)

Wilderness Water Temperature (pgs 41 - 50) (pdf 416 kb, 11 pages)