APPENDIX A 

 DETAILED METHODOLOGY 



1. Details of Talus Bed Measurement and Data Processing Methodology . 



An initial dive was made to calibrate depth gages of all divers and 

 to verify criteria for use in determining the inshore and offshore bound- 

 aries of the talus bed. The north side had an irregular fill base (where 

 rock and talus meet), and a heavy sediment overburden downslope which 

 made the talus boundary difficult to determine. 



Using a steel tape, a metered line, and an underwater slate, one 

 diver made the first measurement of the rock revetment, holding the free 

 end of the 30.5-meter steel tape on an azimuth perpendicular to the 

 cardinal side. When the diver reached the end of the rock revetment 

 (beginning of the talus bed), the depth, distance, and time were re- 

 corded. Three divers then swam to the first diver's location. Measure- 

 ments were taken on the cardinal sides between the points where the 

 angle of the side changed direction (beginning of "wing" of the island) . 

 The first team of two divers measured the talus bed width (inner to 

 outer margin) by having one diver hold the free end of a 50-meter line 

 (marked) in meter intervals) while the sedond diver swam along the per- 

 pendicular azimuth to the outer edge of the talus bed. At this point 

 the second diver recorded depth, time, and distance. The first diver 

 was then signaled to join the second diver at the outer edge. The pair 

 then measured the outer edge of the talus along the entire length of the 

 side, using the method discussed below, A second team of two divers 

 measured the talus along the inner edge. 



Swimming along an azimuth parallel to the side, one diver deployed 

 the steel tape along the inner or outer edge of the talus bed (the 

 second diver held the free end of the tape and remained at the start 

 point) until a change in depth (+^0,15 meter) or direction (^^10°) was 

 noted. At that point the first diver stopped, noted distance swum, 

 depth, and time. The second diver was then signaled to swim to the 

 first diver. From this point the first diver swam up the revetment to 

 the waterline. At the waterline, the diver noted distance and time. 

 He then returned to the bottom where the second diver was waiting. The 

 width of the talus bed was measured from this point to the outer edge 

 where again time, depth, and distance were recorded. The first diver 

 returned to the second diver and repeated the process, moving along the 

 cardinal side. The team on the outer edge used an identical method 

 except that team measured the width of the talus bed from the outer to 

 inner edge. Each time a talus width was measured, the corresponding 

 distance up the revetment (waterline to inner edge of talus bed) was 

 measured. This method allowed multiple points of measurement and 

 allowed divers to observe changes at the outside and inside limits of 

 the bed. 



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