County’s water‑quality TMDL annual report accepted by DEQ; mercury element revised

Benton County staff told commissioners May 16 that the county’s Total Maximum Daily Load (TMDL) annual report for 2021–2022 was accepted by the Oregon Department of Environmental Quality in April 2023.

Daniel Reddick, Solid Waste and Water Quality Program coordinator, described the county’s implementation plan (the DEQ‑approved plan runs five years, with annual status updates) and said the recent DEQ guidance included revised mercury elements that staff have incorporated and will address in a revised implementation plan due in June.

Reddick said the county reports on three primary pollutants (bacteria, temperature and mercury) and that temperature trend analysis is limited by sparse data; staff said they are coordinating with watershed councils and other partners and pursuing grants to expand monitoring capacity.

Commissioners asked about DEQ feedback; staff said DEQ’s primary guidance this cycle focused on mercury requirements and that staff will continue collaborating across departments to ensure implementation.

Next steps: finalize and submit the revised implementation plan to DEQ in June and coordinate with watershed groups and DEQ contacts on monitoring and implementation.