Anna Maria Island Summary & Conclusions

• Prior to construction of the beach nourishment project, beaches in the project area had eroded to the point that structures were threatened by minor storm activity.  Although significant width and nearshore volume has been lost since project construction, the beach restoration project adequately weathered significant storms in March 1993, October 1995, October 1996, and August 1997.  The MHW shoreline 72 months after project construction remains 87 feet wider than pre-construction conditions.  The project area shoreline has receded approximately 121 feet since the post-construction survey in February 1993.  The project area recession is largely due to an adjustment of the beach profile from a construction profile to a wave adjusted (equilibrium) profile.
• The project design specified an initial fill volume of 2,208,000 cubic yards to construct the Anna Maria Island (Manatee County) Shore Protection Project.  The post-construction survey (February 1993) indicated that the contractor placed 2,324,000 cubic yards within the project limits.  The 72-month post-construction monitoring survey indicates that 2,135,800 cubic yards remain within the project limits above the -18 ft. (NGVD) depth contour.   This shows that approximately 97% of the design initial fill volume, or 92% of the placed fill, remains within the project limits.  However, most of the remaining fill is located between the -6 and -18 foot (NGVD) depth contours.
• Based on the post-construction survey, 85% or 1,971,000 cubic yards of the total fill volume, was placed above -6 ft. NGVD.  During the first year following construction, the project lost 854,000 cubic yards above -6 ft. NGVD.  This indicates that the total construction to design shape adjustment occurred in less than one year, driven primarily by the 1993 "Storm of the Century".   Based on the February 1999 survey, 880,200 cubic yards or approximately 45% of the placed fill remains above the -6 foot (NGVD) contour.
• The 72-month post-construction survey indicates that the fill transition section constructed at the south project limit had a positive effect on project performance.  The transition helped stabilize the nearshore features of the project such as MHW shoreline location.  Results of the 72-month post-construction survey provide some evidence that the fill transition helped to reduce the level of volumetric losses to the -18 foot (NGVD) contour; in fact the project area has been accretional overall since project completion from R-32 to R-36.  The transition sections at the southern terminus of the project should be maintained in future renourishment operations.

• The December 1992 survey was conducted prior to the initial 1992/93 beach nourishment project, and is considered the baseline for beach volume comparisons.  Comparison of the December 1992 beach to the May 2003 beach indicates that approximately 3.4 million cubic yards of material (83% of the placed volume) remain landward of the -18 foot (NGVD) contour within the project area.
• One-year post-construction survey (May 2003) indicates nearly 74% of the placed volume remains landward of the -18 foot (NGVD) contour.  During the two-year post-construction period, sand is expected to continue to move offshore until the system reaches a natural equilibrium slope.
• The shoreline mean high water position has retreated landward by an average of 55 feet throughout the project area and an average of 46 feet over the entire survey area as sand shifts offshore.