Breach History and Susceptibility Study, South Jetty and Navigation Project, Grays Harbor, Washington
ENGINEER RESEARCH AND DEVELOPMENT CENTER VICKSBURG MS COASTAL AND HYDRAULICS LAB
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The purpose of this study was to analyze the December 1993 breach at Grays Harbor, WA, and assess the threat to the Federal Navigation Project had the breach not been filled the following fall. The study was conducted by quantifying evolution of breach morphology numerically simulating the ocean wave and water level conditions producing the current through such a breach, including investigation of wide-area implications for the current in Grays Harbor and numerical modeling breach evolution. Available data on the breach evolution were analyzed with a Geographic Information System. The width of the breach and erosion of the adjacent shoreline are quantified from aerial photographs. Shoreline position and bottom configurations in the vicinity of the now-closed breach are the basis of numerical modeling of wave- and tide-driven currents. Estimates are made of the wave and current climate at South Beach, Pt. Chehalis, and in Half Moon Bay under the assumption of a breach at the jetty. Hydrodynamics for various alternatives of further erosion of the breach are modeled to evaluate flow patterns in a developed breach condition. Sediment transport and evolution of the breach are modeled to assess the potential for continued breach growth and longterm assessment of breach stability. Study products are intended to assist the U.S. Army Engineer District, Seattle, in developing a long-term management plan for protecting Federal navigation project features.
- Information Science
- Physical and Dynamic Oceanography
- Operations Research