REGIONAL COASTAL ENGINEERING STUDIES – ORANGE COUNTY, CA

Client: U.S. Army Corps of Engineers, Los Angeles District

Since the 1940s, the northern portion of Orange County, California has been extensively modified by human activities that include harbor construction, river mouth stabilization, and the provision of more than 10 million cubic yards of beach nourishment. Coastal Frontiers was selected to undertake a wide-ranging study of coastal processes in this region in support of the U.S. Army Corps of Engineers' Coast of California Storm and Tidal Waves Study - Orange County.

Bolsa Chica State Beach

Study Tasks

  • Summarize wind and current data applicable to the nearshore region

  • Conduct a fluorescent tracer study of sediment movement in the Laguna Beach pocket beaches

  • Analyze sediment input to the littoral zone from both major and minor fluvial sources

  • Evaluate historical bathymetric changes, including a detailed consideration of subsidence induced by petroleum withdrawal

  • Evaluate littoral sediment losses at Newport Submarine Canyon

  • Prepare preliminary and final budgets of sediment for the Seal Beach Littoral Cell, the Huntington Beach Littoral Cell, and the Laguna Beach Mini-Cells

  • Evaluate historical beach volume and shoreline changes, including a detailed consideration of the effects of beach nourishment at Surfside-Sunset and West Newport

A key breakthrough resulted from the application of a statistically-derived depth of closure to the bathymetric survey data obtained during the past six decades. Once this technique was implemented, it became possible to track the increase in the volume of shorezone sediment that resulted from the periodic nourishment activities.