30 



degree of wind direction variability, typically on time scales of the synoptic meteorology 

 (i.e., 2-4 days). Close inspection of the wind vector record reveals that on April 17, the 

 large storm waves were associated with low atmospheric pressure and strong southerly 

 winds. In contrast, the storms on April 8 and 10 caused strong northeasterly and northerly 

 winds, respectively. 



The wave records from March through May 1996 (lower two tiers in Figure 3-4) 

 illustrate five storm events attaining significant wave heights greater than 3 m, one of which 

 (on April 17) had waves exceeding 5 m. 



Table 3-3 



Duration Intervals and Significant Wave Heights of Major Storms during the Period from 

 January 1993 through May 1996 as Observed by NOAA Buoy 44007 



Time 







Significant Wave Height (m 





Period 

















>3 



>4 



>5 >6 



>7 





Events 



31 



18 



11 



1 







1/93- 



Ave. Duration (hr) 



8 



6 



2 



3 





1/94 

















Total (hr) 



263 



122 



28 



3 







Events 



15 



6 



4 











2/94- 



Ave. Duration (hr) 



6 



5 



1 







2/95 

















Total (hr) 



96 



32 



7 









Events 



26 



14 



7 



3 



1 



3/95- 



Ave. Duration (hr) 



7 



4 



3 



1 



1 



5/96 

















Total (hr) 



203 



67 



24 



4 



1 



3.3 Assessment of Currents and Physical Processes 



3.3.1 Analysis of Near-Bottom Currents 



The three consecutive deployments of moored instrumentation at PDS yielded nearly 

 complete records of near-bottom currents, water temperature, pressure, and relative turbidity 

 over the period from February 27 to May 14, 1996. To illustrate the temporal variability in 



Oceanographic Measurements at the Portland Disposal Site during Spring of 1996 



