EXECUTIVE SUMMARY 



Under the Disposal Area Monitoring System (DAMOS) Program for the U.S. 

 Army Corps of Engineers, New England Division, Science Applications International 

 Corporation (SAIC) conducted an Oceanographic Measurement Program at the Portland 

 Disposal Site (PDS) located 13 km east of Cape Elizabeth in the Gulf of Maine. A single 

 instrumented tripod was deployed from February 27 to May 14, 1996, in order to acquire 

 site-specific data on tides and near-bottom currents, water temperature, and turbidity. The 

 tripod was deployed in the southwest corner of the PDS, in a region of relatively rough 

 topography having a water depth of approximately 60 m. Overall, the 78-day 

 measurement program provided excellent data from which to characterize near-bottom 

 currents and turbidity, and evaluate the physical processes governing bottom sediment 

 resuspension within the PDS. 



Vertical profiles of temperature, salinity, and density were acquired at a single 

 location in the PDS during February, April, and May 1996, respectively. The February 

 profile revealed a water column that was very weakly stratified, as is typical for the coastal 

 Gulf of Maine in winter. Water property characteristics during late April and mid-May 

 illustrated that relatively fresh and warm water had been introduced to the surface layer, 

 presumably as a result of river discharge. Beneath a moderate thermocline and pycnocline, 

 water properties were nearly constant throughout the lower half of the water column during 

 late spring. With regard to the vertical density stratification, it is apparent that the entire 

 water column to a depth of 60 m is very weakly stratified throughout winter and early 

 spring, whereas the introduction of relatively fresh/ warm waters at the surface during mid- 

 spring causes considerable stratification that may tend to decouple horizontal currents and 

 other transport processes within a two-layer water column. 



Time series observations of winds, waves, atmospheric pressure, and surface water 

 temperatures were acquired from NOAA buoy 44007, located 6 km southwest of the PDS, 

 to assess the seasonal and inter- annual variability in meteorological conditions from 1993 

 through 1995, as well as meteorological conditions during the 1996 measurement program. 

 Analysis of the annual wave statistics revealed that wave characteristics were very similar 

 for the 3.4 years of wave records. Significant wave heights less than 2 m occurred from 

 90 to 95% of the time during each year. The maximum significant wave height observed 

 in each of the four measurement years ranged from 5.6 to 7.3 m. Overall, wave 

 characteristics during the first half of 1996 were typical of other recent years at this 

 location. 



Analysis of the seasonal variability in wave conditions at the PDS revealed that 

 mean significant wave heights were 1.2 m in winter (December through February) and 



