126 



No dredged material was present in any replicate photograph obtained from the 

 three reference areas. Camera penetration depth ranged from 3.0 cm to 9.6 cm, and was 

 shallowest at WEST REF (Table 3-10). Despite the relatively low penetration, sand-over- 

 mud layering was observed in all replicate photographs from NE REF and in two replicate 

 photographs from NLON REF Station 2. No evidence of mud was seen at WEST REF. 



All of the reference areas were predominantly characterized as fine to very fine 

 sand (Table 3-10). At NE REF and NLON REF, the major modal grain size was 4 to 3 

 phi (very fine sand) in all but one photograph from NE REF. NE REF Station 4 had a 

 major modal grain size of >4 phi (silt/clay). At WEST REF, the sediment was mostly 3 

 to 2 phi (fine sand). WEST REF Station 5 was dominated by 2 to 1 phi (medium sand). 



All of the reference area REMOTS® photographs showed low boundary roughness. 

 Averaged boundary roughness values for the stations ranged from 0.4 cm to 1.6 cm and 

 were attributed to biogenic activity. 



The apparent RPD depth ranged from 0.7 cm to 2.9 cm at the reference stations. 

 The average RPD value was 1.76 cm at WEST REF, 1.04 cm at NE REF, and 1.51 cm at 

 NLON REF (Table 3-10). Two REMOTS® photographs at WEST REF (Station 2/B and 

 Station 6/B) showed no RPD and indications of low apparent DO conditions within the 

 bottom waters. No redox rebound layers were detected in any of the 1995 reference area 

 photographs. 



In general, the reference areas displayed a solid Stage II benthic community with 

 progression into Stage II on III at all but two stations (NE REF Station 2 and NLON REF 

 Station 4; Table 3-10). Dense amphipod tube mats were present at all three reference 

 areas. The replicate image obtained from WEST REF Station 6/B was classified as azoic, 

 while the remaining two photographs (obtained within a 25 meter radius) displayed healthy 

 Stage II and Stage III benthic communities. This suggests a very recent and highly 

 localized benthic disturbance. 



Median OSI values ranged from +4 to +8 at the reference stations during the 1995 

 survey, with an overall average of +5.9. This shows a slight improvement in overall 

 benthic conditions, relative to the August 1992 survey despite one replicate photograph at 

 NLON REF (Station 2/B) and two replicates at WEST REF (Station 2/B and Station 6/B) 

 showing evidence of low DO conditions or enrichment. No methane gas was apparent in 

 any replicate image. 



Monitoring Cruise at the New London Disposal Site, 1992 - 1998 



