BEACH REPLENISHMENT EXPERIENCE ALONG THE EAST FLORIDA COAST: A HALF-CENTURY OF PROGRESS IN SHORE PROTECTION

The east coast of Florida accounts for about 27% of the total length of erosional beaches in Florida. Shore protection options are limited in the southeast Florida coastal segment by intensive commercial development, which makes relocation or abandonment economically or technically unfeasible. Shore protection measures of choice therefore focus on periodic placement of sand along the shore by dredging or bypassing. Of the 583 km of sandy shore along the Florida east coast, 117 km have been artificially renourished over the last half century. This 20% of shoreline length that has been renourished is mainly associated with urbanized coastal sectors. The 143 nourishment episodes spanning the time frame 1944 to 1996 involved the placement of 86 million cubic yards of dredged sand at a total cost of more than 200 million dollars. Although total overall costs averaged about $3.85 million per year since 1944, decadal costs have escalated to the point where they averaged about $8.45 million for 1986-1996. Although placement costs averaged over the last half century figure about $4.88 per cubic yard, with extreme high costs in the range of $16 - 20 per cubic yard, the average recent decadal cost for sand dredged offshore and placed on the beach comes in around $11.93 per cubic yard. An economically viable method of shore protection, the procedure is not without fault as increasing environmental concerns surfaced as the practice became more common. Adaptation of sand dredging and pumping operations to natural cycles of turtle nesting, manatee and whale migrations, and shorebird nesting developed with experience as did concerns for anoxic conditions in borrows, turbidity in the water column, siltation of coral-algal reefs, and beach-fill encroachment onto inshore hardgrounds. Offshore reserves of beach-quality sand are limited along the southeast coast and in some areas supply is becoming increasingly problematic. Lessons learned over the last half-century show that beach replenishment is a practical and environmentally friendly approach to shore protection.