1J_ 



than 5 mg l ). One potential source of this low-end variability is associated with the 

 characteristics of the measurement medium. For example, the laboratory calibration used 

 filtered seawater that may have had significantly different concentrations and particle size 

 characteristics of any remaining suspended solids compared to the "background" 

 conditions of the near-bottom water at the Portland measurement site. Consequently, when 

 the relative turbidity data from the Portland field site were converted to suspended solids 

 concentrations using the laboratory calibration equation, some of the low-end values 

 resulted in concentrations less than zero (e.g., see Figures 3-1 la and 3-1 le). Because this 

 low-end uncertainty had no adverse effect on the analyses or interpretations of this study, 

 no attempt was made to modify the turbidity calibration equation. 



2.2.4 Water Column Profiling Instrumentation 



Water column profile measurements were acquired using a SeaCat Conductivity- 

 Temperature-Depth (CTD) profiling instrument manufactured by Sea-Bird Electronics, Inc. 

 to characterize water properties at the site of the moored instrument array. On three of the 

 four trips to the site, the SeaCat was lowered to the seafloor to acquire data from near the 

 surface to within a few meters of the seafloor. During profiling operations, the SeaCat 

 sampled conductivity, temperature, and pressure (instrument depth) at 1-sec intervals, 

 which was sufficient to acquire data at approximately 10-cm intervals through the vertical 

 profile. Following the survey, the CTD data were downloaded, edited, and used to 

 generate graphic data products depicting the vertical structure in water properties at the 

 measurement site. 



2.2.5 Meteorological Observations from NOAA Buoy 44007 



NOAA buoy 44007, located 6 km southwest of the moored instrument site (at 

 43°31.48'N and 70°05.24'W), provided meteorological data throughout the spring 1996 

 measurement program. The data that were most applicable to the present program were 

 wind speed and direction, atmospheric pressure, surface water temperature, significant 

 wave height, and peak wave period (the period of the wave having the peak spectral 

 density). Buoy data were acquired electronically from NOAA for the period from January 

 1993 through May 1996 and archived with the moored current data from the Portland 

 Disposal Site. 



In general, the NOAA buoy provided good-quality data for all parameters and the 

 3.4 years of data were adequate to develop annual and seasonal statistics for all 

 meteorological parameters of concern. 



Oceanographic Measurements at the Portland Disposal Site during Spring of 1996 



