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Mapes Creek

Threatened Coho Salmon
Fish Passage
Community Resilience


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  1. Pre-assessment (Completed)
  2. Project Design (Completed)
  3. Construction Started (Completed)
  4. Construction Finished (In Progress)
  5. Monitoring Active

Mapes Creek Culvert Replacement

The Kilchis Basin in an important watershed for salmonid conservation on Oregon’s north coast. It has been designated as Salmon Anchor Habitat by the Oregon Dept. of Forestry (ODF) and the Wild Salmon Center, making it a high priority for culvert replacement projects. This project removed one of the most significant culvert barriers in the watershed by replacing an undersized and failing culvert with a 32 ft concrete bridge. It also included reconstruction of approximately 100 ft of stream bed following stream simulation guidelines.

The new bridge is ~1.5 times as wide as the Mapes Creek’s channel and the restored streambed matches the natural streambed upstream. As a result, the new bridge will provide unimpeded passage for a variety of aquatic organisms including the federally threatened Oregon Coast coho salmon. It also will improve stream function by reducing potential for downstream erosion and allowing for proper sediment and nutrient transport.

Further, the new structure meets current seismic safety standards and will not be prone to plugging with woody debris and streambed materials like the culvert it replaced. the County’s maintenance crews will no longer have to regularly remove debris from the inlet of this structure (like they did for the culvert that was replaced). This will greatly improve public safety by reducing potential for failure during earthquakes or high flow events and it also will greatly reduce maintenance time and expenses for the Tillamook County Public Works Dept. The new bridge will be on the National Bridge Inventory System and subject to Oregon Dept. of Transportation bi-annual inspections.

Partners: Salmon SuperHwy, US Fish and Wildlife Service,
Tillamook County Public Works, Oregon Watershed Enhancement Board, Oregon Department of Fish and Wildlife, National Fish and Wildlife Foundation, Trout Unlimited