Client: City of Long Beach, California

The City of Long Beach waterfront combines industrial harbors, small craft marinas, and recreational beaches. Despite the sheltering effect of the Long Beach Harbor Breakwater, localized areas have experienced chronic beach erosion. Coastal Frontiers has supported the City's efforts to maintain its beaches through a variety of activities ranging from technical analyses to interactive meetings with interested citizen groups and city officials. The primary study tasks and several key findings are summarized below.

3D Model of Peninsula Beach

Study Tasks

  • Assess local wave, current and water level conditions

  • Supplement quantitative findings with anecdotal evidence acquired from historical photos, maps, news accounts, and interviews with knowledgeable local residents

  • Evaluate the causes of recurring beach erosion

  • Develop and evaluate candidate mitigative measures that include bulkheads, revetments, groins, breakwater extensions, periodic beach nourishment, and sand backpassing

  • Perform a moveable-bed physical model study to evaluate a "perched beach" shore protection concept

Key Findings

Periodic sand backpassing represents a cost-effective means of maintaining the protective capacity of Peninsula Beach due to a favorable combination of source proximity and accessibility. Land scrapers are capable of moving 100,000 cubic yards per year at a cost of less than $2/cubic yard.

A perched beach structure would exacerbate rather than mitigate erosion due to an increase in alongshore current speed.