Ghost Dike Advanced Wetland Mitigation Project
Pacific County, Washington
The Ghost Dike Advanced Wetland Mitigation Project was originally included as part of the Shoalwater Bay Mitigation Bank, but has been advanced as a separate project to establish a mitigation credit supply on a faster timeline than the bank project development.
The Ghost Dike Project generates wetland credits by removing a remnant dike segment that has breached in two locations, filling the borrow ditch that was excavated as a borrow source for dike construction, and re-creating a tidal channel network both behind the dike and outboard of the dike to the edge of the high marsh plant community. Cascade identified the site’s geographic limits, developed all project designs, developed the Advanced Wetland Mitigation Plan, and completed all federal, state, and local permitting for project construction. To guide the project design, Cascade identified appropriate reference sites and integrated the project into the larger estuarine design being developed for the Shoalwater Bay Mitigation Bank.
Mitigation Plan development, and federal and state permitting were completed in 18 months, and the 21 acre site will ultimately generate over 7 mitigation credits to support tribally sponsored projects with the Ghost Dike’s service area. Cascade has also guided the Tribe through Pacific County shoreline permitting process, and construction contractor selection. Cascade will provide guidance throughout project construction and apply salt marsh seed as each construction area is complete. We developed site-specific sediment control BMP’s to address the site’s tidal location, including maintaining a portion of the dike as surface water containment, and repurposing shrubs cleared from the dike as fascines to break wave energy before reaching the work area. The project also includes addressing European dunegrass and nonnative cattail populations within the bank and restoring high marsh vegetation to all disturbed areas.