Inlet History 



Ponce de Leon Inlet has existed as a natural inlet in its approximate present location 

 since at least the time of the Spanish explorer Ponce de Leon when he noted the inlet in his 

 log in 1513 (Jones and Mehta 1978). The first major bathymetric survey was done in May 

 1925 by the Coast and Geodetic Survey. In 1932/33, the Intracoastal Waterway was 

 rerouted to the west of the inlet by dredging a bypass channel, due to problems navigating 

 through the dynamic flood shoal. The inlet became non-navigable and was dredged and 

 surveyed in August 1943 and again in October 1944 by the U.S. Army Engineer District, 

 Jacksonville (SAJ), for the war effort. Prior to jetty construction in 1968, the inlet was 

 recognized as difficult and dangerous to navigate with controlling depths over the ebb 

 shoal of typically 1.2 to 1.8 m. 



Funding for a weir jetty system at Ponce de Leon Inlet was authorized under the River 

 and Harbor Act adopted 27 October 1965. The weir system was designed so that sand 

 moving down from the north would pass through the weir section of the north jetty and 

 deposit in the adjacent impoundment basin. This basin was to be periodically dredged and 

 the sand placed south of the inlet. Construction occurred from 1967 to 1972. Following 

 construction, the project did not perform as anticipated. As early as August 1972 riprap 

 was placed beside sections of the north jetty to provide scour protection. Because the weir 

 section was not functioning as planned, it was partially closed in 1979 and fully closed in 

 1984. The inlet continues to experience shoaling, scour, and navigation problems today. 



There have been several previous field studies of Ponce de Leon Inlet. A partial list of 

 published reports includes: U.S. Army Engineer District, Jacksonville (1963, 1967, 1983), 

 Purpura et al. (1974), Purpura (1977), Hemsley and Briggs (1988), Taylor (1989), Taylor 

 etal. (1990), Taylor, Yanez, and Hull (1992), and Waller et al. (1997) (which is 

 included in this report as Appendix A). 



Data Collection Time Periods 



Three time periods within the 2-year deployment (September 1995 to October 1997) 

 were selected for detailed analyses. These time periods were selected based on data 

 requirements for numerical model development and validation. The parameters for 

 selecting the time periods included: time periods when most or all the in situ gauges were 

 functioning, storm conditions, near-continuous spring-neap tidal cycles, and data 

 coincident with short-term data collection in the fall of 1997. 



20 February - 20 March 1996 



This period was selected because it included a major storm during 8-14 March. The 

 storm's peak on 1 1 March produced wave heights over 5 m, a storm surge of 0.5 m, and a 

 wind speed of 17 m/sec. During this time period all the wave and water level gauges were 

 working, except for one wave gauge on the ebb shoal that failed during the peak of the 

 storm. The current meters were not operational. The main interest in this time period was 

 in modeling the shoaling, refraction, and breaking of the storm waves. 



Chapter 1 Introduction 



