operated at a frequency of 208 kHz and measured depth to a 
resolution of 3.0 cm (1.0 feet), with an accuracy + 10 cm at these 
depths. On 14 November 1985, another bathymetric survey was 
conducted at a location in the eastern portion of the disposal site 
(designated NLON-85) for evaluation as a new disposal point. This 
survey covered an area 900 meters square and consisted of 37 lanes 
900 meters long spaced 25 meters apart (Fig. 2-1). On 23 January 
1986, a post-disposal bathymetric survey was conducted around the 
NLON-85 disposal point. This survey was performed over the 
identical grid as the November baseline survey so that direct 
comparison of the data would reveal the extent of dredged material 
and provide an estimate of the volume of material disposed. The 
November and January surveys were conducted using the Raytheon 
fathometer. 
In July 1986, a bathymetric survey was again conducted 
over the identical survey lanes of the NLON Master survey of 1985. 
Additional bathymetric surveys (designated NLON-85 and NLON-86 in 
Figure 2-1) were conducted to provide 25 meter lane spacing over 
the four disposal mounds (NL-I NL-II, NL-III, NL-RELIC) which 
existed at the disposal site as a result of past disposal 
operations and the area where disposal activities were presently 
occurring (NLON-85). This closer lane spacing provides the 
required resolution for subsequent data analysis and the production 
of detailed depth contour charts. 
Analysis of the bathymetric data standardizes the raw 
depth values to Mean Low Water by correcting for the depth of the 
transducer and for tidal changes during the survey. 
2.2 Side Scan Sonar Survey 
On 28 August 1985, a side scan sonar survey was performed 
at the New London Disposal Site. This survey consisted of 20 lanes 
3100 meters long and spaced 150 meters apart. This resulted ina 
survey area of 3100 by 2850 meters which extended outside of the 
disposal site boundaries in excess of 500 meters in each direction. 
The Klein Side Scan, which was operated at a frequency of 100kHz, 
was set for a range of 100 meters on either side of the towed fish. 
This provided a 50 meter overlap of lane information to insure that 
important features were not missed. 
2.3 REMOTS® Sediment-Profile Photography 
REMOTS® surveys of the New London Disposal Site were 
first performed in June 1984. REMOTS® is used to detect and map 
the distribution of thin (1-20cm) dredged material layers. This 
capability complements the precision bathymetric data which can 
reliably measure bottom elevation changes greater than 15 cm. In 
addition, REMOTS® is used to map benthic disturbance gradients and 
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