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Activities and Potential Rule Changes > Re-evaluating the freshwater
dissolved oxygen criteria in Water Quality Standards
Re-evaluating the freshwater dissolved oxygen criteria in Water
Quality Standards
During the federal review of Washington State’s 2006 rule revision, the U.S.
Environmental Protection Agency (EPA), National Marine Fisheries Service (NMFS),
and U.S. Fish and Wildlife Service (USFWS) expressed significant concern over
the state’s dissolved oxygen (DO) criteria. Their specific concern relates to
the levels of DO in gravel beds, where salmonids spawn and fry develop. Ecology
made a commitment to study some options for addressing dissolved oxygen
criteria, including inter-gravel DO (IGDO), and will propose changes based on
that study. Ecology has assigned a primary researcher to the study, who will
work with an external focus group to formulate a recommendation.Starting in
November 2008, Ecology initiated a project to:
- Discuss the dissolved oxygen criteria used in other western states
and its effectiveness in protecting salmonids.
- Work with EPA and others who participated in past discussion on the DO
criteria to get feedback and recommendations.
- Research new and emerging science related to the relationship between
IGDO and water column D.O. concentrations.
- Assess the feasibility of a percent saturation criteria based on
analysis of historical data in the state.
That report was published September 30, 2009. It does not include
recommendations for revising the freshwater D.O. criteria. That issue will be a
topic of discussion at the Triennial Review.
For more information, please contact:
Susan Braley
Water Quality Program
Washington Department of Ecology
P.O. Box 47600
Olympia, WA 98504-7600
Phone: 360-407-6414
Fax: 360-407-6426
e-mail: SWQS@ecy.wa.gov
Easy-to-read version (Ecology
publication)
Code Reviser Version (Washington State Legislature Page)
Waters Requiring Supplemental Spawning
and Incubation Protection for Salmonid Species (Ecology publication)
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Last updated
October 2009
Copyright © Washington State Department of Ecology. See http://www.ecy.wa.gov/copyright.html.
