netere per second 



Figure 1 0. Near-bottom current vectors along each transect for 30 September 

 1997 



been exposed by the erosion of overlying sand and gravel or whether they are 

 hydraulically mobilized. Because grain sizes of the samples at the basin entrance 

 (an area often requiring dredging) are "large," it is likely that even if there is an 

 exposed glacial till in the vicinity, large cobbles, whether liberated from the till or 

 from other sources, are mobilized and transported southward. 



Figure 12 shows that most of the sediments inside the basin are small with 

 D50S ranging from 0.25 to 16 mm. A line of coarse material (DsqS ranging from 

 1 6 to 32 mm) exists between 1 8.3 and 27.4 m (60 and 90 ft) offshore to the north 

 of the basin. Fine-to-medium sand exists further offshore to the northeast of the 

 basin, while coarser material occurs closer to the basin and to the southeast. 



16 



Chapter 3 Field-Data Collection 



