communication cables. The manufacturer-stated accuracy for current speed measurement 

 is ± 0.2 cm/sec. 



The data collection boat was outfitted with a Global Positioning System (GPS) receiver 

 antenna. U.S. Coast Guard GPS transmitter beacons, positioned at various locations 

 along the Florida coast, provided differential GPS positioning for a higher level of 

 accuracy during the data collection. The outputs from these instruments were interfaced to 

 a laptop computer using a hydrographic surveying software system known as HYPACK. 

 This combination permitted accurate logging of location from a known GPS starting 

 coordinate at each velocity profile transect. The data collection boat traversed the transect 

 line at a slow constant speed (approximately 4-7 km/hr) to obtain the best possible spatial 

 coverage. 



The data collection transect lines throughout the study area were located to provide the 

 best information to support the modeling effort. However, certain field conditions were 

 encountered, such as shallow flats, marshes, and shoal migration near the inlet, that 

 necessitated transect line locations be moved, shortened, or lengthened in order to obtain 

 the full discharge and flow patterns within the cross sections. 



Neap Tide Data Collection 



Plate A3 illustrates the location of the areas monitored for the data collection effort 

 during trip one. During this first survey, a priority was placed on the collection of 

 bathymetric information, as well as the ADCP data. Therefore, the first day's effort 

 covered numerous transect lines in the bay areas. Table Al summarizes the ADCP data 

 collected on 25 August 1997. It contains line numbers, times (EST), and discharges for 

 the areas in the south bay, north bay, and ICWW. Direction of the total discharge flow 

 listed in this table is presented as flood or ebb flow and indicated by + and -, respectively. 

 Except for the summary table of the intensive surveys, the tables and Plates summarizing 

 the data collection are presented in chronological order and not in order of line number. 

 Chronological order presentation of the data was selected because the transects were not 

 monitored by sequential line number order. Plates A4-A7 present the depth-averaged 

 velocity vector plots for data collected on 25 August. The integration of the GPS 

 coordinates for each vertical profile along the transect line accurately defines the location 

 of the velocity vector data shown in the Plates. Transect lines with velocity vectors that do 

 not plot from bank to bank indicate that either bank movement or shallow water areas were 

 encountered during the data collection. For the purposes of data presentation, the arrow 

 shows flow direction and the velocity magnitude is indicated by the adjacent number. All 

 the Plates showing velocity vectors are plotted at the same scale. The Plates for each day 

 are in order of time. 



The intensive ADCP survey of the inlet area was conducted on 26 August. The 

 discharge data are summarize^ in Table A2, but are not plotted. Table A3 presents a 

 summarizes of the 27 August data collection effort, which was concentrated in the north 

 bay and the ICWW areas during ebb flow conditions. Depth-averaged velocity vector data 

 for the transects in these areas are shown in Plates A8-A12. Bathymetric and ADCP data 

 were collected on the ebb shoal on 28 August "Die ADCP discharges for this area are 



Appendix A Velocity and Discharge Measurements at Ponce de Leon, FL Ao 



