Water Quality

Oregon's 2004/2006 Integrated Report consists of:

  • An assessment database with information on water quality for waters in Oregon (includes water quality limited waters and 303(d) list waters).
  • The assessment methodology used to evaluate data.
  • A schedule to develop TMDLs for waters identified in the Section 303(d) list.
  • A report titled Oregon's 2004 Water Quality Assessment Section 305(b) Report (submitted to EPA July 2004).

Assessment Process

DEQ began the biennial water quality assessment process by preparing a Draft Assessment Methodology and issuing a public call for submitting data and comments (April 1 to May 16, 2003).

DEQ evaluated water quality data for Oregon's waters using the "decision rules" in the Assessment Methodology for Oregon's 2004/2006 Integrated Report on Water Quality Status. DEQ assigned an assessment status category to each water body where data were available to evaluate. Water bodies that do not meet water quality standards are Water Quality Limited and are assigned Category 4 or Category 5. Water bodies in Category 5 need pollutant Total Maximum Daily Loads (TMDLs) developed and comprise the Section 303(d) list.

A public review and comment period on the draft list of water quality limited waters was open from September 9, 2005 to Nov. 7, 2005. The final list and Integrated Report reflect the public comments and changes made in response to comments. DEQ updated and revised Oregon's TMDL Priorities and Schedule based on the final 2004/2006 Section 303(d) list of Category 5 waters.

Water bodies assigned to Category 4 or Category 5 are Water Quality Limited. Water bodies assigned to Category 5 are water quality limited and need a TMDL developed (Section 303(d) list). DEQ has updated and revised Oregon's TMDL Priorities and Schedule based on Oregon's final 2004/2006 Section 303(d) list of Category 5 waters.

DEQ submitted Oregon's 2004/2006 Integrated Report and Section 303(d) list to EPA for review on May 23, 2006. EPA approves only the waters identified under Section 303(d) as needing TMDLs. DEQ made minor changes to the final 303(d) list during EPA's review.

EPA approved Oregon's 2004/2006 Section 303(d) list on Feb. 26, 2007. 

2004/2006 Integrated Report