Thursday, January 28, 2010
why putting rock on the beach is a bad idea.
"coastal armoring" [also called shoreline/coastal protection structures and hard structures]
coastal armoring protects infrastructure (roads, houses, water treatment plants, parking lots...) NOT the beach from coastal erosion.
riprap revetments (engineered rock that is placed on the shoreline to protect property from coastal erosion) - example: rock proposed at Sloat Blvd.
and seawalls (vertical walls that are built in front of structures or along cliffs to stop coastal erosion) - example: O'Shaughnessy Seawall on northern OB
coastal armoring can cause the following NEGATIVE impacts to the beach:
1. passive erosion - the rock or seawall cause additional coastal erosion to occur down-drift and on the edges of the structure.
2. placement loss - rocks placed on the beach cover the beach and at high tide can block lateral access on the beach.
3. active erosion- beaches can narrow due to changes in beach dynamics and wave reflection.
4. public access issues - rock can block beach access and cause dangerous conditions for beach users and surfers.
MORE INFO AT:
Surfrider Website -
Scientific NOAA document titled: The Impacts of Coastal Protection Structures in California's Monterey Bay National Marine Sanctuary
UCSC Professor Gary Griggs article on California's Eroding Shorelines