Lower Columbia-Sandy Subbasin TMDL

DEQ held two rulemaking advisory committee meetings for the Lower Columbia-Sandy Subbasin. The role of the rulemaking advisory committee was to advise DEQ on the following: 

• Economic and fiscal impacts of the proposed rules for entities impacted by the proposed TMDL 
  
• Revision of required TMDL elements with a focus on the TMDL allocations to be updated based on the current temperature criteria for the Lower Columbia-Sandy Subbasin project area
  
• Revisions to the Water Quality Management Plan
  

Committee documents

• Advisory Committee Charter​
  

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​​​​Meeting 2: April 5, 2023

• Agenda
  
• Meeting summary​
  
• Presentation Slides​
  
• Draft Fiscal Impact Statement (clean version)
• Draft Fiscal Impact Statement (redline version of changes made since RAC 1)
• Draft Water Quality Management Plan, Lower Columbia Sandy Subbasin, Temperature and Bacteria 
• ​Draft Water Quality Management Plan, Lower Columbia Sandy Subbasin, Temperature and Bacteria ​- Redline version
• Draft Total Maximum Daily Loads for Lower Columbia-Sandy Subbasin-Temperature 
  
• ​Draft Total Maximum Daily Loads for Lower Columbia-Sandy Subbasin, Temperature - Redline version
  
• ​​Lower Columbia-Sandy Subbasin Technical Support Document
• Shade and Temperature Buffer Summary
  
• Temperature and Shade Values 
• Climate Change and Stream Temperature in Oregon

• Agenda
  
• Meeting Summary​
  
• Meeting Presentation​
• Draft Total Maximum Daily Loads for Lower Columbia-Sandy Subbasin, Temperature
• Lower Columbia-Sandy Subbasin Quality Assurance Project Plan
• Draft Water Quality Management Plan, Lower Columbia-Sandy Subbasin, Temperature
• Draft Fiscal and Economic Impact Statement, Lower Columbia-Sandy Subbasin  
• ​Draft Oregon Administrative Rule Language​​

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Public comment

The comment period closed at 4 p.m. on Feb. 26, 2024.

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

Supporting documents

• Columbia-Sandy Subbasin Total Maximum Daily Loads for Temperature (adopted, by reference, into rule) – Updated 1/18/24
  
• Columbia-Sandy Subbasin Water Quality Management Plan (adopted, by reference, into rule)
• Columbia-Sandy Subbasin TMDL Technical Support Document – Updated 1/18/24
  
• Appendix A: Model Report – Updated 1/18/24
  
• Appendix B: Sandy River Temperature Model Configuration and Calibration Report (Prepared by Tetra Tech)
• Appendix C: Sandy River Model Scenario Report (Prepared by Tetra Tech) – Updated 1/18/24
  
• Appendix D: Bull Run River (USGS 14138850 to confluence with Sandy River) Temperature Model Report (Prepared by Portland Water Bureau)
• Appendix E: Bull Run River Surrogate Measure
• Appendix F: Climate Change and Stream Temperature in Oregon: A Literature Synthesis
• Appendix G: Stream Buffer Width Literature Review
• Appendix H: Assessment Units addressed by Temperature TMDLs for the Lower Columbia-Sandy Subbasin
  
  

Public hearing

Online only, Feb. 16, 2024.
DEQ held a public hearing to present information, answer questions, and accept comments. The hearing was held remotely via Zoom and was open to everyone

• Presentation Slides
  

Webinars

Webinar 2: March 21, 2023, 2 p.m. PT
DEQ held an informational webinar about the Temperature Total Maximum Daily Load Replacement for the Lower Columbia-Sandy Subbasin. The webinar provided an opportunity to exchange questions and answers about the technical approach to revising the TMDL.

• Presentation Slides

Webinar 1: Jan. 31, 2023 

DEQ held an informational webinar about the Temperature Total Maximum Daily Load Replacements for the Lower Columbia-Sandy Subbasin and the Willamette Subbasins. The webinar provided information about the rulemakings and the technical approach to revising the TMDLs and the Water Quality Management Plans.  

• Presentation Slides​