Willamette Subbasins Temperature TMDL

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This TMDL project includes the following Willamette Subbasins:Coast Fork Willamette, McKenzie, Middle Fork Willamette, Upper Willamette, Middle Willamette, Molalla-Pudding, North Santiam, South Santiam, Lower Willamette, and Clackamas Subbasins. 

This project does not include waterbodies in the Tualatin Subbasin, Yamhill Subbasin, the Willamette River mainstem, and most of the major tributaries to the Willamette River. The temperature TMDLs for the Willamette River mainstem and major tributaries (exact extent summarized below) will be developed as a separate project with rule advisory meetings expected to begin in 2023 and scheduled for EPA approval or disapproval by Sept. 15, 2024.

Waterbodies in the Willamette mainstem and major tributaries project area include: 

• Willamette River including all side channels and sloughs from the confluence of the Columbia River to the confluence of Coast Fork of the Willamette and Middle Fork of the Willamette Rivers (approximately river mile 187)

• Multnomah Channel

• Clackamas River up to River Mill Dam/Estacada Lake (approximately river mile 26)

• Santiam River (all 12 miles) North Santiam River up to Detroit Dam (approximately river mile 49) 

• South Santiam River up to Foster Dam (approximately river mile 38) 

• Long Tom River to Fern Ridge Dam (approximately river mile 26)

• Middle Fork Willamette to Dexter Dam (approximately river 17) 

• Fall Creek to Fall Creek Dam (approximately river mile 7) 

• Coast Fork Willamette to Cottage Grove Dam (approximately river mile 30) Row River to Dorena Dam (approximately river mile 7.5)
  

DEQ held two rulemaking advisory committee meetings for the Willamette Subbasins. 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 Willamette Subbasins project area
  
• Revisions to the Water Quality Management Plans

Advisory committee documents

• Advisory Committee Charter
• Advisory Committee Roster
  

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​Meeting 2: April 6, 2023

• Agenda
  
• Meeting summary​
  
• Meeting presentation​
  
• Draft Fiscal Impact Statement (clean version)
• Draft Fiscal Impact Statement (redline version of changes made since RAC 1)
• Draft Water Quality Management Plan, Willamette Subbasins, Temperature
• Draft Water Quality Management Plan, Willamette Subbasins, Temperature - Redline version​
• Draft Total Maximum Daily Loads for Willamette Subbasins, Temperature​
  
• ​​​​Draft Total Ma​ximum Daily Loads for Willamette Subbasins, Temperature​ - Redline version​
• Willamette Subbasins Technical Support Document
• Shade and Temperature Buffer Summary
• Temperature and Shade Values
• Climate Change and Stream Temperature in Oregon​
  

​​​Meeting 1:  Feb. 23, 2023

• Agenda
  
• Meeting Summary​
  
• Meeting Presentation​
  
• Draft Total Maximum Daily Loads for Willamette Subbasins, Temperature
  
• Willamette Subbasins Quality Assurance Project Plan
• Draft Water Quality Management Plan, Willamette Subbasins TMDL, Temperature
  
• Draft Fiscal and Economic Impact Statement, Willamette Subbasins
  
• Draft Oregon Administrative Rule Language
  

Public comment

The comment period closed at 4 p.m. on March 15, 2024.

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

Supporting documents

• Willamette Subbasins Total Maximum Daily Loads for Temperature (adopted, by reference, into rule)
• Willamette Subbasins Water Quality Management Plan (adopted, by reference, into rule)
• Willamette Subbasins TMDL Technical Support Document
• Appendix A: Heat Source Model Report
• Appendix B: Lower Willamette Shade Model Memo (prepared by City of Portland Environmental Services)
• Appendix C: Potential Near-Stream Land Cover
• Appendix D: Assessment Units addressed by Temperature TMDLs for the Willamette Subbasins
• Appendix E: Southern Willamette Shade Results
• Appendix F: Lower Willamette Shade Results
• Appendix G: Climate Change and Stream Temperature in Oregon: A Literature Synthesis
• Appendix H: Shade Gap Map
• Willamette Subbasins Shade Gap Map
• Appendix I: Stream Buffer Width Literature Review
• Appendix J: McKenzie River CE-QUAL-W2 Model Scenario Report (Prepared by Tetra Tech)
• Appendix K: McKenzie River Wasteload Allocation Scenario Model Report
  

Public h​earing

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
  

Webi​nars

Webinar 2:  March 22, 2023
DEQ provided an informational webinar about the Temperature Total Maximum Daily Load Replacement for the Willamette Subbasins. 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 provided 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