Milwaukie planning commission backs ‘no net loss’ floodplain standards, recommends city council adoption

The Milwaukie Planning Commission on a unanimous vote recommended that Milwaukie City Council adopt amendments to the city’s flood-hazard regulations to implement “no net loss” standards for key floodplain functions.

City senior planner Brett Kelvorp told commissioners the draft changes respond to recent federal guidance and aim to keep Milwaukie eligible for the National Flood Insurance Program. "I've been working on this, this code amendment project related to our flood hazard ordinances," Kelvorp said, outlining provisions that increase mitigation requirements and add protections for floodplain storage, water quality and riparian vegetation.

The amendments add specific mitigation ratios and a new riparian buffer zone (RBZ) that is measured as 170 feet from the top of bank within mapped floodplain areas. Under the draft rules, fill that reduces flood-storage capacity would generally require a 2:1 replacement ratio; new impervious surface within the regulated floodplain must be balanced on a 1:1 basis or addressed with green-infrastructure measures; and tree removal of 6 inches diameter or greater would require replacement at a 3:1 ratio. The draft also includes a “beneficial gain” standard requiring developers to plant vegetation on an area equal to 5% of a project area in addition to mitigation when development occurs in the floodplain.

Kelvorp told the commission the changes largely reflect a FEMA-provided model ordinance and the biological opinion driving updates at the federal level. He said communities were asked to make a preliminary decision quickly and that Milwaukie had chosen to pursue a path consistent with the model language. "We were provided with a couple options including, kind of a model code or some model ordinance language," he said.

Commissioners asked about the scope and applicability of the new standards. Kelvorp clarified the RBZ and RBZ fringe apply only inside the mapped 100-year floodplain: "Both the RBZ and the RBZ fringe only apply within the flood plain," he said, adding that the RBZ stops where the floodplain ends. He also explained how the rules would apply to projects already with land-use entitlements but not yet permitted for construction: where a project had not submitted building permits, the new Title 18 standards would apply at the time of building-permit issuance.

A member of the public, Jeremy Wood of Milwaukie, asked staff to clarify how to view the most current flood maps. Kelvorp pointed him to FEMA’s Map Service Center for the official maps and offered to review local GIS mapping after the meeting.

Vice Chair Edge and multiple commissioners praised staff for quickly preparing the draft and the supporting findings. Edge described the effort as the product of a long, multiyear process tied to litigation and a federal biological opinion and said the commission should move forward: "I'm really happy to support this tonight," Edge said.

After discussion the commission voted to recommend approval of file ZA-2024-003 as presented by staff. The motion was moved and seconded; commissioners voted unanimously to forward the recommendation to Milwaukie City Council, which will hold a separate public hearing and decide whether to adopt the amendments.

The amendments would be added to Title 18 of the Milwaukie Municipal Code and are intended to preserve the city’s participation in the National Flood Insurance Program by aligning local regulations with federal expectations. Staff noted the federal rulemaking process is not yet final and that additional adjustments could be needed once the National Environmental Policy Act (NEPA) review and related federal documents are completed.

The commission closed the public hearing and moved on to other agenda items, convening subsequently as the Community Involvement Advisory Committee and discussing meeting cadence and commissioner recruitment.