The exception to this was a group of stations in the center of the 

 survey, all with higher OSI values (+9 to +10) . OSI values were 

 indeterminate at REF-2 and ranged from +6 to +11 at the other 

 reference stations. The OSI frequency distribution for the 

 disposal site was similar to the reference stations, with +9 the 

 major class interval for each (Figure 3-13) . 



4 . DISCUSSION 



The objectives of this survey were to assess the areal 

 extent of dredged material and determine the level of benthic 

 recolonization at the disposal site. These goals were met almost 

 completely, although delineation of the southwestern boundary of 

 the deposit was not accomplished (Figure 3-3) . The mapped 

 distribution of dredged material was based principally on REMOTS® 

 photographs, since bathymetric techniques proved inadequate due to 

 the lack of a pre-disposal baseline survey and the absence of a 

 well-defined disposal mound at the buoy position. 



Several factors contributed to the presence of dredged 

 sediment beyond the REMOTS® survey boundaries. The greatest 

 influence was most likely due to positioning error of the disposal 

 barges relative to the center of the REMOTS® survey. Scow logs 

 indicated that a large portion of disposal took place up to 50 m 

 south and west of the buoy. This was in agreement with the 

 distribution of dredged sediments seen in REMOTS® photographs, 

 which showed that most of the material lay southwest of the survey 

 center (Figure 3-3) . 



It is also possible that some dredged material was 

 partially dispersed beyond the limits of the REMOTS® survey. 

 Evidence of elevated current speeds was seen in REMOTS® 

 photographs. Bed formations were observed at both REF-2 and in the 

 central and southern regions of the disposal site (Figures 3-4 and 

 3-7) . The two layer stratigraphy of coarse-over-fine dredged 

 material (Figure 3-4) also indicated that winnowing of the upper 

 sediment surface had occurred. Currents in this area were probably 

 tidal in nature, because the bottom was too deep (>30 m) to be 

 influenced strongly by local storm events. However, it is unlikely 

 that these currents would be sufficiently high to either erode or 

 prevent the formation of a disposal mound. Other disposal areas, 

 such as the New London Disposal Site, have been shown to exhibit 

 stable mounds over long time periods despite the presence of strong 

 tidal currents (SAIC, 1990) . 



The amount of dredged material outside the boundaries of 

 the REMOTS® survey was difficult to estimate. A conservative 

 estimate for the volume of dredged sediment present in the REMOTS® 

 survey was calculated by multiplying the areal extent of observed 

 dredged material (76,700 m 2 ) by its maximum observed depth (14.6 

 cm), producing a volume estimate of 11,200 m 3 . This represented a 



