July 1986 Survey 
The July 1986 survey included individual sampling grids 
at each of the five disposal mounds as well as at the southwest 
corner of the disposal site to detect the presence of dredged 
material outside the site boundaries. Distinct dredged material 
layers were evident in the vicinity of the NL-85 disposal point 
(Figures 3-38 and 3-39). The perimeter of the NL-85 mound was 
similar to that observed in January 1986, with the exception of 
station 500E. In January, station 500E exhibited a dredged 
material layer 3.29 cm thick. In this survey, dredged material was 
not detected at station 500E. This may be explained either by 
local patchiness near the edge of the mound or by bioturbational 
mixing of the thin flanks of the deposit. Such mixing can erase 
evidence of a pre-existing surface layer of deposited material, 
especially when it is thin relative to the mean particle 
bioturbation depth. This phenomenon was documented at the flanks 
of the Field Verification Program (FVP) mound at CLIS during the 
first year of monitoring (Germano and Rhoads, 1984). The apparent 
absence of dredged material at all stations immediately adjacent 
to the NL-85 disposal mound indicated that either no dispersal of 
material from the mound to the surrounding bottom had occurred or 
that the disposed material was so thin that it could not be 
detected in the REMOTS® photographs. In the past, dredged material 
layers as thin as 0.1 cm have been detected. If thin layers of 
dredged material were deposited, however, rapid bioturbation can 
mix such layers with the underlying (ambient) sediments. For these 
reasons, the designation of "NDM" in Figure 3-38 indicates that the 
REMOTS® photographs contained no definitive information about the 
presence of dredged material. Such material may have been present 
in small quantities. No dredged material was observed at the New 
London Reference station. In addition, dredged material was not 
detected at any stations in the southwest reconnaissance grid. 
Surface sediments at most stations within the disposal 
site consisted of very fine to fine sand (4-3 phi to 3-2 phi, 
Figure 3-40). At the other stations where the sediment grain-size 
major mode was silt-clay (>4 phi), all but one were comprised of 
thin sand layers overlying fine-grained sediments (see Figure 
3-38). Eighteen of the twenty replicates taken at the Reference 
station showed a major mode of fine sand (3-2 phi), while two 
replicates exhibited very fine sand (4-3 phi). The relatively 
diverse and layered distribution of sediment grain-size at the New 
London Disposal Site likely reflected inputs of heterogeneous 
dredged material, as well as diverse ambient bottom textures. 
The western side of the southwest reconnaissance grid 
consisted of medium sand (2-1 phi) and the eastern side consisted 
of predominantly coarse sand (1-0 phi, Figure 3-41). Unlike the 
disposal site, the sediment grain size samples in this area 
consisted largely of bivalve shell fragments derived from venerid 
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