SOUTH COAST - Wondering about those large single boulders strapped onto flatbed trucks rolling north? The massive granite rocks, that can weigh up to 30 tons each, are headed to the Coos Bay North Spit, where they are being loaded onto barges to be shipped north to the mouth of the Columbia River, to be used to repair the North Jetty there.
The boulders are coming from all over, but the ones being spotted on U.S. Highway 101 in the past few weeks are originating from Foster rock pit, located just south of the KOA campground south of Langlois. The rock pit, owned by Carl Foster, is located on the east side of the highway.
This 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, according to Catworks Construction, one of the contractors on the project. 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.
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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.
The U.S. Army Corps of Engineers finished refurbishing the mile-long “A” Jetty in 2017, according to an article in the Chinook Observer. Work on North Jetty, which is located near Waikiki and Benson beaches at Cape Disappointment State Park, began in February 2018. Work stopped during the winter months, then resumed this March and is on schedule and expected to be completed this November. Restoration of the South Jetty will start this year and last through about 2023.
The three jetties at the mouth of the Columbia River were built between 1885 and 1939, according to the U.S. Army Corps of Engineers. They’ve each received periodic updates, but the notoriously rough conditions on the Columbia Bar have taken a toll. Waves constantly batter the rocks and river and ocean currents eat away at the jetties’ foundations and change the contours of the shipping channel. The jetties play a critical role in the region’s economy by making it safer for ships to navigate the bar.