SEDIMENTS, SHALLOW SUBBOTTOM STRUCTURE, AND SAND RESOURCES 

 OF THE INNER CONTINENTAL SHELF, CENTRAL DELMARVA PENINSULA 



by 



Michael E. Field 



I . INTRODUCTION 



1. Background . 



Ocean beaches and dunes constitute a vital buffer zone between the 

 sea and populated coastal areas, and also provide much needed recreation 

 areas for the public. The construction, improvement, and maintenance of 

 beaches through the placement (nourishment) of sand on the shore is one 

 of several protection methods. This technique has gained prominence in 

 coastal engineering largely as a result of the successful program initi- 

 ated at Santa Barbara, California, in 1938 (Hall, 1952). 



Where a specified plan of improvement involves shore restoration and 

 periodic nourishment, large volumes of sandfill may be needed. In recent 

 years it has become increasingly difficult to obtain suitable sand from 

 lagoonal or inland sources in sufficient quantities and at an economical 

 cost for beach-fill purposes. This difficulty is due in part to increased 

 land value, depletion of previously used nearby sources, and added cost 

 of transporting sand from areas increasingly remote. Material composing 

 the bottom and subbottom of estuaries, lagoons, and bays is often too 

 fine grained and unsuitable for long-term protection. Regardless of the 

 source of replacement material, the loss of some fines is inevitable as 

 replacement beach sediment seeks equilibrium with its environment. How- 

 ever, it is possible to estimate the amount of material that will be 

 lost through sorting in the surf zone by a quantitative comparison of 

 the placed material with the native material and therefore minimize 

 losses through selection of the most suitable fill material (Krumbein 

 and James, 1965; James, 1974; Hobson, 1977). 



The problem of locating suitable sand supplies led the Corps of 

 Engineers to a search for new unexploited deposits of sand. The search 

 focused offshore with the intent to explore and inventory deposits suit- 

 able for future beach-fill requirements. This exploration program is 

 conducted through the U.S. Army Coastal Engineering Research Center 

 (CERC) . 



In 1964, a program was initiated to survey offshore regions of the 

 Atlantic, Pacific, gulf, and Great Lakes coastal areas to delineate the 

 character of sand deposits. Formerly called the Sand Inventory Program, 

 it began with a survey off the New Jersey coast . Subsequent surveys have 

 included the Inner Continental Shelf off Florida, Texas, New England, 

 New York, Maryland, and parts of North Carolina, Delaware, Virginia, 

 California, and Lakes Michigan and Erie. Recognizing a broader applica- 

 tion to the CERC mission of information collected in conduct of the 

 research, the program is now referred to as the Inner Continental Shelf 



