Littoral Environment Observations and Beach Changes Along the Southeast Florida Coast.
Abstract
Daily and weekly surveys and observations of the beach and nearshore were made at Jupiter, Boca Raton, and Hollywood, Florida, for 4 1/2 years between 1969 and 1973. During this relatively storm-free period, mean annual breaker height varied from a high of 0.9 meter at Jupiter, the northernmost site, to 0.5 meter at Hollywood, the southernmost site. This decrease in wave energy reaching the shoreline is attributed to the varying protection afforded by the Bahama Banks, 80 kilometers offshore of Hollywood. Wave and longshore current directions were observed to change seasonally, with directions from the northeast dominating during October through March and from the southeast during April through September. Potential gross longshore transport rates, estimated from these data, ranged from 1,800,000 cubic meters per year at Jupiter to 1,200,000 cubic meters per year at Boca Raton, to 480,000 cubic meters per year at Hollywood. The magnitude of beach changes, as defined by shoreline position and sand volume on the beach, decreased from north to south and is relatively low compared with typical U. S. east coast beaches. Contributing factors include the sheltering effect of the Bahama Banks, the lack of significant storms, and the underlying coquina limestone which characteristically crops out just below the MSL shoreline, forming a protective reef that effectively retards erosion. Beach changes were seasonal in nature, but were reversed at Boca Raton, where beach width and sand volume were highest during the winter months. Seasonal beach changes were two to three times greater than year to year changes.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1977
- Accession Number
- ADA047608
Entities
People
- Allan E. Dewall
Organizations
- Coastal Engineering Research Center