PART II: MONITORING PROGRAM 



Objectives 



19. There were two basic objectives of the Carolina Beach monitoring 

 program. First was a determination of the adequacy of the trap in the inlet 

 to serve as a primary source of beach nourishment material for the project. 

 This required measurement of the volume of material accumulating within the 

 trap over various periods of time and the volume loss of fill from the shore 

 protection project over corresponding periods. In addition to the volume 

 measurements obtained through surveys, evaluation of trap performance required 

 tide and wave data collection, analysis of accumulated sediment properties for 

 comparison with beach sediment characteristics, and tidal flow measurements in 

 Carolina Beach Inlet. The second objective was to assess the impact of the 

 inlet throat trap on the inlet's ebb tide channel and delta. Relatively small 

 traps had been dredged in the throat of Carolina Beach Inlet in 1967 and 1968 

 under a CERC research program to determine the impact of such a trap on the 

 channel and delta. These traps had volume capacities of about 100,000 cu yd. 

 Following dredging of the traps in 1967 and 1968, a channel developed through 

 the inlet's ocean bar. A third dredging of a trap in 1970, however, failed to 

 produce any change, and assessments of the impacts of the trap on the ocean 

 bar were inconclusive. The larger capacity trap, approximately 400,000 cu yd, 

 created by the 1982 emergency fill offered an excellent opportunity to reexam- 

 ine the effects of a trap on the ebb tide channel and delta. 



Data Collection 



20. The monitoring program extended over a 42-month period from April 

 1981 through September 1984. The basic activities comprising the effort were 

 hydrographic surveys of the inlet trap and ocean bar; tidal current measure- 

 ments in the throat of the inlet; beach onshore and offshore profile surveys; 

 aerial and ground photographic coverage of the beach; sediment sample collec- 

 tions and analyses; continuous wave and tide gaging; and daily visual observa- 

 tion of wave direction. The daily visual observations of wave direction were 

 eliminated from the program. The frequencies at which various activities were 

 to be accomplished are shown in Figure 6. The emergency beach fill placed on 



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