measured parameters is relatively large. Using calibration 

 techniques established under the DAMOS program, recorded position 

 accuracies within the CLIS disposal site are ± 1-2 meters. 



A comparison of the contoured bathymetric charts of the 

 FVP site in March 1985 (Figure 2-2) and October 1985 (Figure 2-3) 

 indicates slightly greater depths (approximately 10 cm) occurring 

 on the mound during the October survey. Vertical depth profiles 

 for both surveys for the lanes where the mound is located reveal 

 the lack of any significant changes in bathymetry (Figure 2-4) . 

 Because an increase in depth of 10 cm is less than the level 

 detectable by the system when the combined errors in depth 

 recording and navigation are considered, it is difficult to 

 conclude that an actual increase in depth has occurred. Due to 

 the small area covered by the mound, the volume of material 

 involved in a 10 cm change in depth would also be quite small. 

 The depths at the mound compare well with those found during the 

 September 1984 survey where the minimum water depth at the peak 

 of the mound was also approximately 18.3 meters. 



An analysis of the volume difference between the 

 surveys conducted in March and October indicated no significant 

 change in volume. Over the entire 800 x 800 meter area of the 

 survey, the accuracy for detecting changes in volume within the 

 95% confidence limit (given the total accumulated errors due to 

 fathometer accuracy, vessel speed, vertical motion due to wave 

 interference, survey lane spacing, etc.) was ± 9852 m 3 . The 

 volume difference was calculated to be -5244 m 3 , well within the 

 non-significant range. An additional calculation was made of the 

 volume difference between a smaller survey conducted during the 

 CLIS survey in August 1985 and the October 1985 survey. Because 

 of the reduced area of the survey, the accuracy for detecting 

 volume change within the 95% confidence limits was ± 4462 m 3 . 

 The calculated change in volume was 50 m 3 , again indicating no 

 significant gain or loss of volume between August and October. 



3.0 REMOTS # Sediment-Profile Photography 



The purpose of the October 1985 FVP REMOTS* survey was 

 to monitor potential change in the sediment characteristics of 

 the dredged material mound, to document the process of benthic 

 infaunal successional recovery of the FVP disposal site, and to 

 monitor changes in the ambient fauna and sediments adjacent to 

 the FVP site. This survey was conducted 29 months after the 

 disposal operation, and one month after Hurricane Gloria. 

 Hurricane Gloria moved through central Long Island Sound on 27 

 September, 1985 with maximum wind speeds of 145-161 km/h (90-100 

 mph) . This extremely high energy event was capable of disturbing 

 the seafloor throughout the CLIS disposal area. The REMOTS® data 

 obtained in October were examined with this consideration. 



The results of the October survey were also compared 



2 



