coarse sand is present in all three borings. This layer correlates with 

 the Pleistocene acquifer of Rasmussen and Slaughter (1955) and Weigle 

 (1974) and probably marks the base of the Pleistocene, No peats were 

 encountered in either the borings or the core; plant material recovered 

 near the surface in the landwardmost boring is modern dune grass. Surface 

 textures across the subaerial part of the barrier island show remarkable 

 consistency. The central and back-barrier sands are all medium-sized 

 overwash deposits and resemble the beach sands in all parameters. On the 

 shoreface there is no evidence of these high-energy, medium-sized sands; 

 sands dominant seaward of the surf zone are fine grained and well sorted. 



In summary, the barrier spit is evolving by several different pro- 

 cesses, each of which varies in importance according to the specific 

 location. Spit building, washover deposition, and inlet filling are all 

 locally important in redistributing sediments eroded from the beach and 

 shoreface. Sediments aggrading on the shoreface probably do not exceed 

 in volume those eroded from the shoreface as the submarine part of the 

 barrier island translates landward. A variation in subsurface lithology 

 along the coast is the rule rather than the exception. This is because 

 each segment of the coast has experienced a different history. The loca- 

 tion of fluvial, estuarine, and tidal channels has a strong bearing on 

 each segment. Secondly, as the barrier retreats it intersects older 

 landforms lying at different orientations and different altitudes, hence 

 some sections of the barrier have a shallow subsurface "core" of Pleisto- 

 cene sediments, and other segments do not. This is a characteristic of 

 barrier islands in general (Field and Duane, 1976), and has been demon- 

 strated for numerous coastlines; two well -documented examples are the 

 Georgia sea island coast (Hoyt and Hails, 1967) and the North Carolina 

 Outer Banks (Pierce and Colqhoun, 1970). 



2. Requirements for Beach Restoration and Characteristics of Beach Sands . 



The conditions of erosion along the northern Delmarva coast, discussed 

 previously, led the U.S. Army Engineer District, Baltimore, to design a 

 plan of improvement for the shoreline. That plan called for construction 

 of groins along the Maryland coast and addition of large quantities of 

 sand for beach erosion control and hurricane protection (U.S. Army Engi- 

 neer District, Baltimore, 1972). Similar plans are being designed for 

 the Delaware coast by the U.S. Army Engineer District, Philadelphia. 



Original designs for the Maryland shoreline called for extensive 

 beach restoration along much of the coast. A summary of the requirements 

 are shown in Table 6. More than 9.2 million cubic meters (12 million 

 cubic yards) would be required for initial construction with an additional 

 60.4 million cubic meters (79 million cubic yards) needed for maintenance 

 over a 50-year timespan, if the entire project is implemented. If only 

 the Fenwick Island and Ocean City improvements are made, the fill required 

 for initial construction will be about 3.4 million cubic meters (4.4 mil- 

 lion cubic yards), with an additional 3.5 million cubic meters (4.6 mil- 

 lion cubic yards) required for 50 years of maintenance. 



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