Lane County adopts emergency erosion-prevention rules to meet Willamette Basin Mercury TMDL

Lane County commissioners on Aug. 26 adopted an emergency ordinance and a companion Lane Manual order to extend erosion-prevention requirements across the county—s portion of the Willamette River Basin to comply with the Willamette Basin Mercury Total Maximum Daily Load (Mercury TMDL). The board voted 5-0 on a roll-call to pass Ordinance 2506 and then unanimously approved Order 25081207.

The ordinance adds TMDL-specific language to Lane Code chapters 9, 11 and 15 and amends the Lane Manual chapter 9 to align county practice with the Mercury TMDL administered by the Oregon Department of Environmental Quality (DEQ). Staff described the action as a minimal, outcomes-based approach that extends existing erosion-prevention outcomes already applied inside municipal separate storm sewer system (MS4) areas to the larger TMDL area, which covers about 76% of Lane County.

The change comes because DEQ—s Mercury TMDL sets a Sept. 3, 2025, implementation deadline for counties to adopt water-quality management requirements. Staff requested emergency enactment so the ordinance and order would be effective before that deadline.

Staff presentations were led by Lorena Janeski, Stormwater Permitting Specialist, and Maurya (Maria/Maurya in materials) Papagalo, Environmental Engineering Supervisor. They told the board the Mercury TMDL requires counties to ensure that erosion, sediment and waste management controls are used and maintained at construction sites from initial clearing through final stabilization. The county will meet the TMDL by incorporating additional TMDL language into Chapter 9 while keeping the previously adopted MS4 code intact for Eugene and Springfield urban growth boundaries.

Rather than creating a new permit program for the TMDL area, staff proposed an outcomes-based code approach: projects must meet positive erosion-control outcomes by using best management practices (BMPs) such as silt fences, waddles, erosion blankets and vegetated buffers. The proposal also extends facility-permit thresholds and MS4-style requirements to work within public rights of way performed by private parties. Staff said the outcomes approach gives contractors flexibility about which BMPs to use while ensuring protection of waterways and adjacent properties.

To support program implementation, staff will continue to use a self-certification form at development permit intake as an educational tool and will place a notification statement on building-permit documents to alert applicants to the new requirements. Staff also said the county will maintain an education-first enforcement program and offer on-site technical assistance and handouts to help compliance. The TMDL requires an education and enforcement program; staff noted enforcement is intended as a last resort.

Because monitoring, outreach, on-site assistance and enforcement across the extensive TMDL area will require staff time and resources, the code allows for a minimal fee for self-certifications and program administration. The ordinance does not set a specific dollar amount; staff said the fee will be adopted later through the county—s fee adoption process and will not be retroactive.

During deliberations commissioners asked whether the proposal meets DEQ requirements; staff said DEQ had provided tentative approval of the county—s approach pending DEQ—s formal review. Commissioners also emphasized that the board may choose in the future to adopt standards that are more protective than DEQ minimums. County counsel conducted a roll-call vote for the ordinance; all five commissioners voted yes. The companion order to amend the Lane Manual likewise passed 5-0 after a brief clarification of the correct order number (25081207).

The board closed the public hearing after staff presentation and no public testimony was offered in person or online. Staff will return with a fee proposal for formal adoption and continue DEQ reporting. The ordinance, order and supporting materials state the county—s intent to limit the TMDL-area program to lands within the Willamette River Basin portion of Lane County rather than countywide.

Ending: The new code language is now adopted under emergency authority and will be in effect while staff completes the formal fee adoption process and DEQ completes its review. Staff said they will continue outreach and technical assistance to developers and contractors as the county implements the new TMDL-area requirements.