Comparison of the performance of three adjacent and differently constructed beach nourishment projects on the gulf peninsula of Florida

Detailed beach-profile monitoring was conducted at the three phases of Sand Key beach nourishment on the Gulf Coast of Florida. The nourishment at Ind ian Rocks Beach, Indian Shores, and Redington Beach was monitored during si x years, four years, and eight years respectively after nourishment. Quarte rly or more frequent beach and nearshore profile surveys were conducted in order to determine short-term (1 gear) and long-term (4 to 8 years) rates o f shoreline and beach-nearshore volume changes. The overall performance of the Sand Rey beach nourishment is excellent. Redington Beach project has al ready exceeded the design Lifetime of 7 gears, and Indian Rocks Beach and I ndian Shore projects are likely to exceed the design lifetime. The measured beach-nearshore volume loss is small: 31% at Indian Rocks Beach over six y ears, 30% at Indian Shores over four years, and only 10% at Redington Beach during eight years. Performance of beach nourishment is influenced by many factors. Those that are directly related to the three nourishment projects include: (1) relativ e location in the regional longshore sediment transport regime, (2) magnitu de of wave energy, (3) sediment characteristics of the borrow material, (4) local reversal and/or gradient in longshore transport, (5) presence of har d structures, (6) adjacent beach nourishment, (7) variation of shoreline or ientation, and (8) sand transfer and beach-fill construction technique. The shoreline and beach-nearshore volume change patterns at the three nourishm ent projects were different due to the different degrees of influence from the above factors, however, construction style is deemed to be an important contributor. The much less costly dragline and conveyor-belt transfer tech nique used in the construction of Indian Shores project does not prove to b e most cost effective for long-term performance.