Six conditions set for CorpsClatsop County says certain portions of the U.S. Army Corps of Engineers' plan to repair the south Columbia River jetty don't comply with county land-use rules. But the project can receive the thumbs-up with some additional measures.
In a letter to the Corps last month, the county identified six conditions of approval for the project, which involves shoring up failing sections of the north and south jetties. The $14 million project, tentatively set to begin next year, is designed as a short-term repair effort to prevent further deterioration of the century-old jetties until funding can be obtained for a more ambitious rehabilitation project.
Corps officials worry that the jetties, weakened by years of storm currents and undercut by erosion, could be breached, allowing sand to clog the shipping channel at the mouth of the river.
The Corps isn't required to obtain a permit from the county, but it must submit its plans to the county for review under the local land-use rules.
In its letter, submitted to the Corps July 28 during a 30-day public comment period, the county agreed that the project is critical to preserving the jetties and protecting the Columbia River navigation channel. But it noted that parts of the project might not comply with regulations governing construction in the Columbia River Estuary.
The project as planned includes the construction of a temporary off-loading platform and road near the base of the south jetty for transporting large rocks to the site.
The T-shaped pier would consist of sheet piling filled with rock or dredge material. The nearby estuary will also be dredged to allow passage to and from the platform for the barges.
As one of its six conditions, the county asked the Corps to show why a pier built on pilings would not work instead, in line with language in the county comprehensive plan that states construction on piling is preferred to fill. If the sheet-piling structure is the only viable option, to Corps is required to prepare a plan to mitigate for the area that would be filled.
The county also asked the Corps to test and identify sediments in the dredging areas, and coordinate the dredge work with local fishing groups, including the Columbia River Crab Fisherman's Association, to minimize impacts on nearby fisheries.
In-water work must follow state and federal recommendations on timing to avoid impacts on fish, and disturbed riparian vegetation must also be replanted.
Kathleen Sellman, Clatsop County Community Development Department director, said the county doesn't expect the project to be held up by the conditions. One unknown factor, however, is the response from other agencies - the last condition requires county review for any additional mitigation projects required by any state or federal department in connection with the jetty project.
"If another agency required something to be done in the county, such as mitigation, we need to take a look at that," she said.
Project manager Norm Tolonen from the Corps said the county's conditions should not present a major hurdle to the project. Any dredging work, for example, will require that sediment samples be taken first, he noted.
The sheet-pile pier was deemed the most efficient design both from a cost standpoint and from the fact that there would be less run-off from the surface, Tolonen said. But the contractor chosen for the project will ultimately pick the most workable design, he said.
"We're not dictating a design to the contractor," he said.
Past repair projects at the jetty - the last was in 1982 - also used a temporary platform for delivering rock, Tolonen said.
The South Jetty was constructed in 1896 and extended in 1914, and the North Jetty was built in 1917. Both have been repaired several times since their construction, but several years of especially heavy storm activity have weakened the structures, which are also being threatened by the erosion of the sand on which they sit.
The Corps is planning a major rehabilitation of both jetties, but the time required to get approval and funding for that project would leave the structures vulnerable for several more years, which is why the agency is pursuing the short-term repair project, Tolonen said.
"We think it's pretty important," he said.
A jetty at the entrance to Coos Bay breached unexpectedly a few years ago. "Once it was broken through, it did not take long to open up a gap, and sand started coming through the channel," he said.
More information on the jetty project is available online at (www.nwp.usace.army.mil/issues/jetty/cms/home.asp)