Lane County staff outline outcomes‑based approach to meet Willamette Basin mercury TMDL; self‑certification, education emphasized

Lane County staff on April 29 described a proposed, outcomes‑based erosion prevention program to meet requirements in the Willamette Basin mercury total maximum daily load (TMDL). The draft approach would apply only within the Willamette Basin portion of Lane County and is intended to be minimally prescriptive while meeting Department of Environmental Quality (DEQ) expectations.

"The Mercury TMDL requirements are meant to protect those waterways and the natural resources, that we all, know are a key reason of why we like to live, work, and play in Lane County," said Lorena Chaneyzewski, Stormwater Permitting Specialist, summarizing the TMDL’s intent during the board work session.

Key elements of staff’s proposal: - Geographic scope: the code would apply to lands in the Willamette River Basin within Lane County (about 76% of the county area), and would not expand county MS4 requirements beyond their current urban boundaries. - Outcomes‑based rules: rather than prescribing a single best management practice, the draft would require construction and land‑disturbing projects to meet erosion, sediment and waste‑material management outcomes using appropriate BMPs (for example, silt fencing, vegetative cover or erosion‑control blankets). - No new county permit in TMDL area: staff said the Mercury TMDL does not require Lane County to adopt a separate county erosion prevention permit for the TMDL area, so the draft code would rely on education, self‑certification and existing compliance pathways rather than a new county permitting layer. - Self‑certification and education: applicants would sign a self‑certification form at permit intake acknowledging the outcomes they must meet; staff emphasized an “education‑first” enforcement approach and said on‑site technical assistance would be offered. - Coordination with DEQ: projects that already require DEQ construction stormwater permits (typically larger disturbances) continue to be regulated by DEQ; staff said DEQ has been consulted and given tentative approval to the proposed approach.

Timing: staff said DEQ set a deadline to adopt local erosion prevention measures by Sept. 3, 2025; staff plan to return with draft code after public outreach and aim for an implementation date of Nov. 1, 2025, if adopted.

Why it matters: the Willamette Basin has elevated mercury levels that can accumulate in fish. Staff framed the proposed, minimally prescriptive model as a way to reduce soil and pollutant discharges to waterways while minimizing added permitting burden on applicants.

Next steps: staff will finish a draft of the code, conduct public outreach to stakeholders and return to the board for public hearings and formal adoption.