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4.0 RESULTS 



4.1 Repetitive Bathymetric Surveys 



CLIS is located in a depositional area of Long Island Sound, characterized by mild 

 bottom current regimes and subject to shallow, wind-driven waves. Since 1984, the 

 DAMOS site management strategy at CLIS has been to create a ring of disposal mounds 

 for the deposition of large volumes of dredged material. The New Haven Capping Project 

 marks the first instance that an artificial containment measure was designed and utilized for 

 the deposition of dredged material. The entire CAD mound development process was 

 observed, scrutinized, and documented by SAIC in support of the DAMOS Program. 

 Results of the precision bathymetry and depth difference analyses for the five surveys 

 conducted at CLIS between September 1993 and March 1994 are presented below 

 including 1) baseline (predisposal), 2) interim disposal, 3) precap, 4) interim cap, and 5) 

 postcap. 



4.1.1 Baseline Survey (19-20 September 1993) 



Results of the baseline bathymetry indicate, with the exception of shallower water 

 depths over the mounds, water depths in the area range from 19 m in the northern half of 

 the surveyed area to 21 m in the southern portion (Figure 1-1). Water depths over the 

 mound centers were as follows: CLIS-87 and CLIS-88 16 m, CLIS-89 17 m, CLIS-90 

 19 m, CLIS-91 19 m, NORWALK 18.5 m, and SP 19.5 m. The historic NHAV-74 

 mound is visible in the southeast corner of the bathymetric chart with a minimum depth of 

 17.0 m before extending beyond the survey area. 



4.1.2 Interim Disposal Survey (23-25 October 1993) 



The interim disposal survey was completed when the federal inner harbor dredging 

 was 50% complete. Development of the mound is readily apparent in the bathymetric 

 analysis of the interim survey (Figure 4-1) when compared to the baseline survey (Figure 

 1-1). The water depth at the center of the NHAV 93 UDM mound was 17.0 m. The 

 depth difference comparison between the baseline and interim disposal surveys (Figure 4-2) 

 showed a mound approximately 400 to 450 m in diameter and 3 m in height. The total 

 volume of the mound based on successive bathymetric surveys was 238,000 m 3 (Table 4- 

 1). 



Monitoring Surveys of the New Haven Capping Project, 1993-1994 



