it can be found in DAMOS Contribution #60 (SAIC, 1989b) . This 

 calculation simply implies that the actual (and unknown) volume 

 difference will occur within the lower and upper confidence limits 

 with a probability of 0.95. 



Figures 3-5 through 3-13 present enlargements of each 

 individual disposal mound using the same data that produced Figure 

 3-1 for the mounds: FVP, STNH-N, STNH-S, CS-1, CS-2, MQR, Norwalk, 

 NHAV-83, and NHAV-74 (Figure 1-1), respectively. Because of the areas 

 defined by the chart boundaries, sections of neighboring mounds can 

 be seen in the figures. Direct comparison of the results of the 1985 

 and 1986 surveys did not reveal any significant changes in topography 

 that could be attributed to erosion. 



3.2 Bathymetry and Side Scan Surveys at Ghost Sites 1 and 2 



Examination of the results of the bathymetric surveys at 

 the GHOST-1 and GHOST-2 sites (Figures 3-14 and 3-15) revealed the 

 lack of any significant accumulation of sediment at any particular 

 location. Because these areas were outside the CLIS area normally 

 surveyed, a comparison with earlier results was not possible. At 

 GHOST-1, the only noticeable variations in depth were on the order of 

 20 cm. At GHOST-2, these variations were only as much as 10-15 cm. 



Analysis of the side scan records for the GHOST-1 and GHOST- 

 2 areas did not identify any large accumulation of dredged material. 

 Figure 3-16 presents the survey lanes and the areas of high 

 reflectance that were evident on the side scan records at GHOST-1. 

 Only one site revealed any distinct reflection and could not account 

 for the 50,000 cubic yards of dredged material suspected of being 

 deposited there. The remainder of the bottom was fairly smooth and 

 uniform. Several areas of high reflectance were scattered throughout 

 the GHOST-2 survey area (Figure 3-17) . Although no distinct areas 

 could be identified as scow loads of dredged material, the difficulty 

 in distinguishing the dredged material from the ambient bottom 

 increases with time. The one identifiable feature at GHOST-2 is a 

 sunken "pocket scow" (Figure 3-17) . 



3.3 REMOTS® Sediment-Profile Surveys at the CLIS Disposal Mounds 



3.3.1 FVP Mound 



The distribution and thickness (cm) of apparent dredged 

 material at the FVP mound (Figure 3-18) was similar to those mapped 

 in earlier surveys. Some stations that were previously shown to be 

 located on the mound and flank perimeter showed no apparent dredged 

 material layer to be present. This may have been caused by either 

 complete mixing of the Black Rock material into the ambient bottom or 

 the loss of high reflectance sediment (ferric hydroxide-coated 

 particles) of the buried pre-disposal surface (datum of reference) . 



10 



