Comparison of the depth matrices from the pre- and postdisposal bathymetric 

 surveys resulted in a volume calculation of 82,972 m s with 95% confidence limits of 

 67,736 and 98,208 m s . This represents the sum of volumes calculated for lanes 12 

 through 27 of the bathymetric survey grid. Examination of disposal logs indicated 

 that an estimated 87,628 m s of material were deposited in this area between pre- and 

 postdisposal surveys. 



32 REMOTS® Sediment-Profile Photography 



Fifteen REMOTS® stations were located at 50 meter intervals to transect the 

 historical CCDS mound. The mound center was located at 41° 49.189'N and 70° 

 24.94TW, based on the postdisposal bathymetric analysis (Figure 3-2). Records 

 indicated that 228,735 and 4,590 m 5 were disposed at this site in 1980 and 1986, 

 respectively. 



A distinct, clearly-defined dredged material layer was not evident in any of 

 the REMOTS® photographs. Ambient grain size at stations 350W and 300W 

 consisted mainly of clay and silt (> 4 phi), with increasing grain size and sand 

 content at stations located closer to the center of the mound (Table 3-1). The 

 maximum grain size observed was at 50W (1-0 phi). The grain size gradient rapidly 

 decreased (4-3 to >4 phi) at station 100E and eastward. 



Sediments observed at stations 100W to 150E generally were sorted more 

 poorly (Figure 3-8) than the more homogeneous sediment profiles observed at 350W 

 and 300W (Figure 3-9). Much of the fine sand component at these stations (100W - 

 150E) appeared to have eroded, leaving behind a layer of shell lag (Figure 3-10). In 

 addition, amphipods and other taxa had reworked the sediment surface extensively 

 and produced a more porous surface layer. The sand appeared to be coarser-grained 

 due to production of grain aggregates by meiofaunal and macrofaunal activities 

 (Figure 3-11). 



Camera prism penetration depths of 11.8 - 14.0 cm were recorded for stations 

 at the western end of the transect (350W and 300W). Mean prism penetrations 

 decreased gradually to 3.1 and 3.9 centimeters at stations located closer to the center 

 of the disposal mound (100W - 150E), as a result of the increase in grain size, shell, 

 and sand content (Table 3-1 and Figure 3-10). Stations farther to the east of the 

 disposal mound showed a general increase in prism penetration with increased 

 distance from the mound, coinciding with the observed decrease in sand content 

 and grain size. Mean prism penetration depths at the transect's eastern end (9.9 and 

 8.4 cm at 300E and 350E, respectively) were approximately 2 - 3 centimeters 

 shallower than penetrations at 300W and 350W. 



The frequency distribution of small-scale boundary roughness was 

 right-skewed with 61% of the photographs indicating values between 0.0 and 0.6 

 centimeters (Figure 3-12). This indicates that no significant disturbances had 



Monitoring Cruise at the Cape Cod Canal Disposal Site and Springhill Beach Site 



