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5.0 CONCLUSIONS AND RECOMMENDATIONS 



The 1997 and 1998 monitoring cruises accomplished both the monitoring objectives 

 at the Western Long Island Sound Disposal Site and the new reference area investigation 

 and characterization tasks at SE-REF. 



Comparisons with the 1996 report showed that a distinct mound, WLIS \, was 

 developed at the 1996-1997 buoy between the D and the G mounds. The I mound 

 contributed to the development of a containment berm and potential basins for future 

 capping operations of dredged sediments. The small to moderate size of the mound was 

 consistent with the volume reported in disposal barge logs. The apron of the I mound 

 appears to cover the area identified at D200S to the east of G mound that had a negative 

 OSI value in 1996. The benthic community on and surrounding the mound indicated a 

 healthy recovery and rapid recolonization rate. Stage I organisms were predominant in 

 September, although several replicates from both the September and March surveys 

 indicated advanced Stage III deposit feeder activity. The I mound, or alternatively the D 

 and G mounds, should be resurveyed in the next monitoring survey at WLIS to monitor the 

 continued recovery and health of the benthic environment over these disposal mounds. 



REMOTS® surveys over the 1995-1996 H mound showed improvements in the 

 benthic conditions. Although the RPD depths in September were slightly depressed due to 

 the seasonal low oxygen conditions, the successional status had advanced since 1996. In 

 March, all replicates indicated feeding voids and, except SOW, a Stage III successional 

 stams and deeper mean RPD depth. 



Seasonal conditions did affect the benthic conditions observed in the REMOTS® 

 sediment-profile photographs. Although hypoxia was not as severe as in previous years, the 

 low dissolved oxygen conditions in the bottom waters did reduce the RPD depths and OSI 

 values in September at both the disposal mounds and reference areas. Redox rebounds were 

 common at the H mound and present at a few stations at the I mound both in September and 

 March surveys. Despite observations of deep RPD depths in March, redox rebounds were 

 visible at the SE-REF which were not seen at the reference areas in September. 



To continue the ongoing development of a containment berm and basins, future 

 disposal mounds may be placed south of G (1), C-E (2), and E-H (3) as well as between H 

 and the namral, steep slope near the southern border of the disposal site. The basins may 

 then be used to optimize capping or isolation of dredged sediments by containing the 

 spread of sediments on the seafloor. A larger basin area could easily be constructed with 

 additional placement of mounds at locations 4, 5, and 6 on Figure 4-1. 



Monitoring Cruise at the WLIS Disposal Site, September 1997 and March 1998 



