Concept Design Option 4: Cobble/Boulder Beach

A cobble/boulder beach design utilizes natural material less susceptible to being washed away to protect the shoreline and bluff from erosion. It involves adding a layer of natural boulders or cobbles to the existing shoreline to supplement material on the beach.

This is similar to the beach in Concept Design Option 3: Groynes with Beach Fill, but would use a larger stone size.

Key Benefits

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Coarse shoreline material prevents some movement

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Variable width to accommodate site-specific erosion concerns



  • Maintains a natural shoreline consistent with what already exists along some of the waterfront
  • Becomes damaged gradually, allowing for continuous minor maintenance



  • Cobbles can be hard to source in large quantities
  • Because of sourcing difficulty, costs can be uncertain
  • More limited resources for design guidance

This option is currently preferred for Reach 7 & 8, and has a rough costing of $31,000/m.