The Coos Bay North Jetty (CBNJ) Major Maintenance Project is located on the north side of the Coos Bay entrance channel. The CBNJ and Coos Bay South Jetty form the Coos Bay federal navigation channel (FNC) entrance that allows for safe transit of vessels into and out of the bay. An attendant feature of the CBNJ is the Log-spiral Bay (LSB), located near the landward root of the jetty. Over time, the LSB has gradually lengthened and enlarged toward the Coos Bay North Spit (CBNS) and the Pacific Ocean.
USACE proposes to repair critical damaged sections to the North Jetty and to fortify the LSB with sand from the FNC in order to maintain stable deep-draft navigation through the entrance into Coos Bay and to prevent breaching of the CBNS during storm events. Repair activities completed now would reduce the risk of jetty failure. The purpose of this task order is to characterize the LSB habitats to better quantify impacts that would result from fortification (filling) approximately 7 acres of the bay with clean sand from the FNC.
This task order involves preparation of a summary report based on existing literature to characterize LSB and Lower Coos Bay estuarine ecology and habitats. The report compiles existing information and data pertaining to intertidal and subtidal estuarine habitats in the lower Coos Bay estuary, including sediment physical and chemical data; biological survey data (benthic invertebrate identification and density calculation); fish surveys (trawls, nearshore sein net surveys, etc.); shellfish surveys (marine clams, mussels, etc.); and submerged aquatic vegetation surveys. This report will be used to supplement USACE’s baseline information and cumulative impacts analysis for the jetty maintenance design project.
Sediment and biological characterization of the Log‑Spiral Bay project area was performed to provide additional baseline data prior to project construction and placement of material. Sampling included sediment physical and chemical, benthic, and epifaunal sample analysis following the Sediment Evaluation Framework. A field survey report and a benthic/epifaunal report summarizing field activities and analytical results were prepared. Lab data were entered into the EIM database.rth Jetty (CBNJ) Major Maintenance Project is located on the north side of the Coos Bay entrance channel. The CBNJ and Coos Bay South Jetty form the Coos Bay federal navigation channel (FNC) entrance that allows for safe transit of vessels into and out of the bay. An attendant feature of the CBNJ is the Log-spiral Bay (LSB), located near the landward root of the jetty. Over time, the LSB has gradually lengthened and enlarged toward the Coos Bay North Spit (CBNS) and the Pacific Ocean.