The federal Clean Water Act requires the Oregon Department of Environmental Quality to assess Oregon's water quality and prepare a report every two years. The Integrated Report is a database that combines reporting information for the Clean Water Act Section 305(b) assessment of all water bodies and the Section 303(d) list of water bodies that do not meet water quality standards. The 303(d) list represents where pollution reduction plans called Total Maximum Daily Loads are needed.
The 2022, Integrated Report represents the state's most comprehensive evaluation of water quality data and information about Oregon's waters. DEQ assessed data and information to determine whether Oregon's waters contain pollutants at levels that exceed protective water quality standards and do not support their beneficial uses. To complete this assessment, DEQ reviewed and assessed readily available data and information for the time period Jan.1, 2016, through Dec.31, 2020, using the Methodology for Oregon's 2022 Water Quality Report and List of Water Quality Limited Waters.
The 2022 Integrated Report categorizes all assessed waterbodies. DEQ evaluated data on whether Oregon's waters are of a high enough quality to meet the most common beneficial uses, such as supporting aquatic life, providing drinking water or supporting recreation. Waterbodies that exceed protective water quality standards are identified as impaired and placed on the 303(d) list. Identifying a waterbody as impaired initiates the prioritization and development of a TMDL.
The categories are:
- Category 1: All beneficial uses are supported, and none are known to be impaired. Oregon does not have sufficiently robust data to be able to use this category.
- Category 2: At least one core beneficial use is supported, and none are known to be impaired.
- Category 3: Not enough information to determine beneficial use support.
- Category 4: Available data and/or information indicate that at least one designated use is not being supported but a TMDL is not needed.
- Category 5: At least one beneficial use is not supported and a TMDL is needed.