County and Consultants Present Draft Channel Migration Zone Maps for Elwha, Indian Creek and Little River

Clallam County planning staff and consultants on Monday presented draft Channel Migration Zone (CMZ) maps for the Lower Elwha River, Indian Creek and Little River and outlined the methods, outreach and next steps for public review.

Bruce, a county planner, said the maps were prepared under a Shoreline Planning grant from the Washington State Department of Ecology to document post-dam-removal channel migration and update technical data in the county's geographic information system. He emphasized the CMZ maps are advisory: "This information is advisory. It's not regulatory in and of itself," Bruce said, adding that only FEMA flood maps are strictly regulatory.

Consultants from Natural Systems Design, including Dr. Tim Abney and Aaron Lee, described how they combined LIDAR, historic aerial imagery, hydraulic modeling and field reconnaissance to delineate the historical migration zone (HMZ), avulsion hazard component (AHC), erosion hazard area (EHA) and disconnected migration areas such as zones behind certified Army Corps levees or where public commitments exist. Aaron Lee said the team used a 2-meter threshold from the channel bed in parts of the analysis to help identify potential avulsion pathways.

Presenters noted dynamics that complicate mapping on the Elwha: the removal of the two dams released stored sediment that altered channel behavior, bedrock canyons that limit migration in some reaches, alluvial fans and debris issues, and interactions with levees and infrastructure. The consultants flagged specific local concern areas including Fox Point and Place Road and discussed the Fox Boy Bluff erosion example where bluff retreat and landslides could result in future inland movement of the bluff crest.

Staff outlined public outreach: a landowner meeting scheduled for May 13 from 6 to 8 p.m., a planning commission review on May 21, and the board's plan to set a public hearing in early June. The county said Department of Ecology has approved the draft maps for review and that agency, federal and tribal partners (including Olympic National Park and state Fish & Wildlife) provided data used in the analysis.

Commissioners asked about private-property impacts and mitigation options. Consultants said the CMZ mapping follows state guidance for a 100-year planning horizon and that site-specific technical information or testimony can alter advisory map conclusions for permit or land-use decisions. They cautioned that structural measures taken by landowners, such as armoring, can have downstream or habitat impacts and may not be permitted without proper environmental review.

County staff said they will continue landowner outreach and that the draft maps are available on the Department of Community Development website; staff encouraged landowners to submit site-specific information during the public review period.