Coweeman Wetland Mitigation Bank, Kelso, Washington

Client—Habitat Bank

The Coweeman Mitigation Bank (Bank) is the first mitigation bank in Washington to offer compensatory mitigation credits for both wetland and fish habitat impacts. The Bank encompasses 300 acres along 1.5 river miles of the Coweeman River in Kelso, including 172 acres of old growth forest. The project is adjacent to the east end of the Coweeman Levee Raise project limits. Due to historic logging practices, river channel morphology has been altered and many of the historic floodplain wetlands and forested floodplains have been lost. The general goals of the Bank project are to restore wetland hydrology and floodplain connectivity, increase habitat connectivity and complexity for salmonids and other aquatic dependent species, create additional wetlands, and re-establish wetland and riparian plant communities typically found in Lower Columbia River floodplain environments.

Gibbs & Olson provided topographic survey of the project. Information collected included key elements such as top of banks, toe of slopes, delineated wetlands, existing trees, fences and river cross-sections. AutoCAD base mapping prepared by Gibbs & Olson included wetland boundaries, visible utilities, utility easements, property boundaries, and a surface model with 1 foot contours.

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