Approximately once a month, surveys were conducted of an area extending 600 m north and south 

 of the pier and approximately 950 m onshore. These surveys were conducted to document the 

 temporal and spatial variability in bathymetry. Contour m^s resulting from these surveys, along 

 with plots of change in elevation between surveys, are given in Appendix A. 



All surveys used the Coastal Research Amphibious Buggy (CRAB), a 10.7-m-tall amphibious 

 tripod described by Birkemeier and Mason (1984), and a Geodimeter electronic surveying system, a 

 Geodim^er 140-T self-tracking, electronic theodolite, distance meter. The profile locations are 

 shown in each figure in Appendix A. Monthly soundings along both sides of the FRF pier were 

 collected by lowering a weighted measuring tape to the bottom and recording the distance below the 

 pier deck. Soimdings were taken midway between the pier pilings to minimize errors caused by scour 

 near the pilings. 



A history of bottom elevations below Gages 645 and 625 is presented in Figure 23 for pier stations 

 7+80 (238 m) and 18+60 (567 m), along with intermediate locations, 323 and 433 m. 



£ -4- 



— -5- 



Distance 



(m) 

 238 



323 

 43 3 



5 57 



JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 

 Month 



Figure 23. Time-history of bottom elevations at selected locations under the FRF pier 



46 



