Willamette Basin Mercury TMDL

On December 30, 2019, EPA established the Willamette Basin Mercury TMDL. Minor changes were made to the TMDL after reviewing comments received during the public comment period, and EPA reissued the TMDL on February 4, 2021. A copy of the final TMDL and related documents are provided below, including a summary of the revisions.

EPA’s TMDL incorporates much of Oregon’s 2019 TMDL, with the major changes being revisions of some of the load and wasteload allocations to ensure that the TMDL meets the mercury water quality standards.

For questions, contact Becky Veiga Nascimento (veiganascimento.rebecca@epa.gov), 208-378-5767.

• Total Maximum Daily Load (TMDL) for Mercury in the Willamette Basin, Oregon (pdf) (573.74 KB, February 4, 2021)
  EPA's final TMDL.
• Summary of Revisions to Willamette Basin Mercury TMDL (pdf) (167.49 KB, February 4, 2021)
  Public comments that resulted in revisions to EPA's 2019 TMDL.
• Transmittal of Final Willamette Basin Mercury TMDL (pdf) (101.74 KB, February 4, 2021)
  EPA's transmittal letter to the Oregon Dept. of Environmental Quality.
• Appendix A: Oregon Dept. of Environmental Quality 2019 Final Revised Willamette Basin Mercury TMDL (pdf) (8.15 MB, November 22, 2019)
• Appendix B: Technical Support Document for TMDL (pdf) (5.82 MB, December 16, 2019)
• Responses to Public Comments on Willamette Basin Mercury TMDL (pdf) (1006.5 KB, February 4, 2021)
  EPA's responses to comments received during the January 6 to February 4, 2020, public comment period.