Marco Island Summary & Conclusions

• The Marco Island Beach Restoration Project was constructed in 1990-1991.  Over 1.2 million cubic yards of sand were placed along three separate fill segments; the north, central, and south beach restoration areas.  The ebb shoals of the adjacent inlets, Big Marco/Capri Pass to the north and Caxambas Pass to the south, were utilized as borrow areas.  The central and south segments were designed to nourish a native section of beach located between the two segments allowing natural processes to transport sand alongshore.  Two terminal groins were installed at the southernmost end of the south beach restoration area to reduce rapid end losses.  In 1996, three segmented breakwaters were installed in the nearshore zone along the southern end of the island to reduce sediment transport into Caxambas Pass.  In 1997, a small beach nourishment project was constructed consisting of over 80,000 cubic yards of sand dredged from the South Borrow Area and placed on the southern 3,000 feet of Marco Island's shoreline.  In 1998 and 1999, two small beach fills were constructed utilizing a total of approximately 12,000 cubic yards of upland sand along the southernmost 1,200 feet.
• The generalized performance of the project continues to be exceptional.  Public perception is positive and supportive.  No adverse impacts resulting from project components have been documented.
• Since completion of construction, the central beach restoration area has experienced an average shoreline advance of 4.1 feet per year.  This is a result of the sheltering effects and the landward and southward migration of Sand Dollar Island.  The entire native beach area has experienced shoreline advance at an average rate of 11.5 feet per year.  This is a result of alongshore transport from the central and south beach restoration areas.  The entire south beach restoration area has experienced shoreline recession at an average rate of 7.8 feet per year.  Note this value includes the nourishment projects from 1997 through 1999.  The erosion is a result of shoreline instability along the southern end of Marco Island and delays in breakwater installation due to permit conditions requiring demonstration of volumetric losses.
• Sand Dollar Island's landward migration has resulted in volumetric gains on average of approximately 24,000 cubic yards per year for the central beach restoration area.  Alongshore sediment transport from the central and south fill areas has naturally nourished the native beach which experienced average volumetric gains of approximately 34,000 cubic yards per year.  The only area with an average historical erosion deficit was the south fill area that averaged volumetric losses of approximately 12,000 cubic yards per year.  The average erosion rate for the south end prior to the beach restoration project was on the order of 25,000 cubic yards per year.