59. Approximately once a month, surveys were conducted of an area 
extending 600 m north and south of the pier and approximately 950 m offshore. 
This was done in order to document the temporal and spatial variability in 
bathymetry. Contour maps resulting from these surveys, along with plots of 
change in elevation between surveys, are given in Appendix A. 
60. 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 Geodimeter 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. Soundings were taken midway 
between the pier pilings to minimize errors caused by scour near the pilings. 
61. 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. 
Distance 
(m) 
238 
Depth, m 
323 
433 
567 
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 
51 
