Approximately once a month, surveys were conducted of an area extending 

 600 m north and south of the pier and approximately 950 m offshore. These 

 surveys were conducted 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. 



All surveys used the Coastal Research Amphibious Buggy (CRAB), a 

 10.7-m-tall amphibious tripod described by Birkemeier and Mason (1984), in 

 combination with a Geodimeter 140-T self-tracking, electronic theodolite, 

 distance meter. Profile locations are shown in each figure in Appendix A. 

 Monthly soundings along both sides of the FRF pier were collected by lower- 

 ing 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. 



A history of bottom elevations below Gauges 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 



323 

 433 



567 



IAN 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 



Chapter 7 Surveys 



47 



