Mouth of the Columbia River North Jetty Lagoon Fill
Location: Cape Disappointment State Park, Ilwaco, WA
This project, the initial phase of a multi-year project to rebuild the North Jetty at the Mouth of the Columbia River, required the import of 125,000 tons of rip rap, shot rock and import sand to stabilize the foundation of the jetty and fill in a large lagoon that had been created by storm action over many years. Additionally, over 50,000 cubic yards of material was excavated from an onsite borrow area in order to provide more sand fill and to create a four acre tidal wetland. Much of this work had to occur during low tides to minimize any impacts to existing wetlands and the Columbia River.
Replacement of a large culvert including a live stream bypass was required along with 11 acres of driftwood placement and dune grass seeding, 16 acres of clearing and invasive species removal, and 4.5 acres of wetland and riparian planting. Restoration of several portions of the mile long Jetty Road, traffic control, significant erosion control and water quality monitoring were also required.
Work was required to commence in October with all work completed during the winter storm season. The major construction and earthwork, including all incidental seeding and roadway repairs were finished 1½ months ahead of schedule which allowed the follow-on contractor to start work several months early thereby eliminating one additional construction season and returning the are to public use one year early.