resulting from winnowing associated 

 with this process appear to be on 

 the order of 10 percent or more, 

 depending on the original bottom 

 material . 



d. Artificial Beach Restoration . 

 The placement of sandfill along a 

 part of shore front for beach 

 restoration may be done in three 

 ways. It may be placed directly 

 onto the shore to be protected or 

 developed as a beach; it may be 

 placed in an area adjacent to and 

 updrift of the area to be protected; 

 or it may be placed offshore. That 

 is, it may be directly placed, 

 placed to form a feeder beach 

 (designed to be eroded by waves and 

 tidal currents and transported via 

 longshore transport to the area to 

 be protected) , or placed as a bar 

 (designed to be transported inshore 

 by waves and currents) . To be 

 effective, offshore restoration 

 must involve placing fill in the 

 zone where shoreward movement of 

 the sand occurs, piling it as high 

 as possible, and placing it during 

 the spring or early summer to take 

 full advantage of the seasonal beach 

 building before the annual period of 

 steep winter storm waves. 



Figure 11. Dredge Chequinquira 



at dock (photo courtesy of 



Woodward-Clyde Consultants) . 



Table 4. Characteristics of fill based on nature of borrow 

 material . 



Nature of Borrow Material 



Characteristics of Fill 



Fairly clean sand 



Silty or clayey sand 



Stiff cohesive soil 

 Soft cohesive soil 



Reasonably uniform fill of 

 moderate density (relative 

 density of 40 to 60 percent) 



Very heterogeneous fill of 

 large void ratio (low 

 relative density) 



Skeleton of clay balls, with 

 matrix of sand and clay 



Laminated normally consolidated 

 or unconsolidated clay. 



63 



