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Powder River Basin TMDL

Adopted rule

Administrative Order No.: DEQ-9-2024
Filed and effective: May 28, 2024
See Oregon Bulletin, June 2024


Rulemaking contact: Vanessa Rose, 971-284-7882

Frequently Asked Questions About the Powder River Basin Bacteria TMDL

The Environmental Quality Commission adopted rules that establish a Total Maximum Daily Load to address the impairments to water quality standards and beneficial uses in surface waters in the Powder River Basin. These impairments are caused by excess bacteria and will be addressed by identifying and quantifying sources of this pollutant. This rule also establishes a water quality management plan that includes pollutant management strategies, a list of parties responsible for developing management plans and implementing strategies, and a timeline to reduce pollutant loads and attain water quality standards.

The Powder River Basin is located in northeastern Oregon and is comprised of the Brownlee, Powder River and Burnt River subbasins, which eventually drain into the Snake River along the border of Oregon and Idaho. 

Visit the Powder Basin TMDL Project web page.
For more information on TMDLs, please visit DEQ's TMDL web page.

In February 2022, the Environmental Quality Commission adopted Oregon Administrative Rules amendments to allow adoption of TMDLs as rules, as well as issued by order, in alignment with authorities in Oregon Revised Statutes. For more information about that rulemaking process, please visit DEQ's rulemaking webpage.

DEQ convened an advisory committee to review the technical issues and fiscal impacts related to the proposed rules. In convening this committee, DEQ appointed members that reflect the range of entities that are both directly and indirectly affected by proposed changes to the rules.

Public comment

DEQ had an initial comment period which closed on Aug. 31, 2023. The second comment period closed at 4 p.m. on March 22, 2024.

For more information, see the Notice of Proposed Rulemaking, which includes the notice and proposed rules.

Supporting documents

  Sign up for email or text updates on this rulemaking via GovDelivery.

Public meetings

DEQ held the following public meetings for this rulemaking:
  • Aug. 15, 2023 – Public hearing
  • Jan.31, 2024 – Informational meeting
  • Feb. 1, 2024 – Open house

EQC action

The EQC adopted these rules at its meeting on May 23, 2024.