Columbia Near-Shore South Jetty

In 2005, a group of public and private sector participants engaged in a collaborative process to explore the use of lower Columbia River maintenance dredge material to stem the depletion of the natural sand volumes in the near-shore environment off of the South Jetty of the Columbia River. The project team was convened by Jim Bergeron, a retired Sea Grant agent and currently a Port of Astoria Commissioner. Project support was provided by Steve Greenwood through the Lower Columbia Solutions Group and Oregon Solutions.

A number of studies documented significant erosion of near-shore sands resulting from the reduction in sediment in the littoral system, in particular a loss of offshore sediment to the mid-continental shelf and near shore region offshore from the Clatsop Plains, resulting in greater wave energy being focused on the jetty and the ocean shore. The ongoing erosion offshore from the south jetty and adjacent areas prompted concern that the south jetty may eventually be undermined or breached through by erosion. The placement of Columbia River dredge material in the near shore area off the south jetty may help to slow this process and prevent further damage to the jetty and erosion of the ocean shore beach.

The long-term objective of a proposed supplementation of dredged sediments would be to keep these sediments in the littoral zone, and rebuild the offshore sands to better protect the jetty from the impacts of waves coming from the southwest.