Pensacola Beach Summary & Conclusions

• Construction of the project resulted in an average advance of the Mean High Water Line of 191 ft (exclusive of tapers).  This average advance reflects a portion of the expected EQUILIBRATION of the beach fill project in which the initially constructed beach berm is expected to recede over the initial stages of the project life.
• Some degree of episodic equilibration has occurred due to the impacts of Tropical Storm Bill at the end of June 2003.  Construction was approximately 85% complete when Bill made landfall.  For comparison, the design construction berm width averaged 225 ft.  In the limit, equilibration of the beach fill project may reduce the beach width to roughly 125 ft.  Until complete equilibration occurs, or, more likely, until tropical storms further impact the shoreline, the beach will remain wider than the predicted post-equilibration design width.

• Shoreline position and beach volume changes over the Year-1 intersurvey period are strongly characterized by the ongoing equilibration process.
• Over the first 9 to 15 months post-construction, the 8.1 miles of Gulf of Mexico shoreline within the project limits receded an average of 53 feet, primarily as part of the equilibration process.  At the same time, volumetric calculations reveal that the sand transported from the upper portion of the beach can be found in the trough area within only a few hundred feet from the shoreline (on average).

• At about 2:25 PM CDT, July 10, Hurricane Dennis made landfall approximately two miles east of Pensacola Beach near Big Sabine Point on Santa Rosa Island.  Pensacola Beach was generally in the weaker leeside eye-wall and experienced winds in probably the category II range (95-115 mph). A peak wind of 93 mph was measured in Pensacola by the National Weather Service.
• Minor beach erosion was sustained along Pensacola Beach.  The erosion did not leave any scarping, and new constructed dunes were not significantly damaged.  A major beach restoration project was completed here in 2003, and the Santa Rosa Island Authority was in the process of nourishing the beach to pre-Ivan design.

• Volume changes measured between May 2004 (pre-Ivan) and May 2007 reveal only minor erosion above -14 ft NAVD88, on the order of 13,000 cy (~0.3 cy/ft).  This result indicates the general success of the renourishment project, the objective of which was to replace the sand volume lost during Hurricane Ivan.  As documented by surveys after each major storm (Ivan, Dennis, and Katrina), significant fractions of the sand lost during these events were transported Gulfward beyond the primary bar.  Survey comparisons to closure indicate that an estimated 2.1 Mcy (approx.) resides at or offshore of the primary bar crest.  Experience from previous storm impacts suggests that this sand will be slow to return to the active beach face, and some portion of the sand volume may likely be carried away by alongshore currents during that process, such that a net loss of the bar sand may occur.