PART V: EXAMPLE APPLICATION 1: MASONBORO INLET, NORTH CAROLINA 



130. The purposes of Parts V and VI, each describing a case study, are 

 to verify DYNLETl and demonstrate how the model Is applied by means of 

 realistic examples. The case study In this chapter, Masonboro Inlet, North 

 Carolina, consists of two tasks: application of DYNLETl and comparison of 

 results with measurements, and review of simple inlet hydrodynamics models 

 developed in the General Investigation of Tidal Inlets (GITI) program. 



131. Masonboro Inlet was the subject of intensive study under the GITI 

 Program (Harris and Bodine 1977) conducted by the USAGE and involved both 

 physical and numerical modeling of tidal flow. Three numerical models, a 

 lumped-parameter model (a lumped-parameter model combines major parameters 

 into a single variable), a one -dimensional explicit finite -difference model, 

 and an explicit two-dimensional finite-difference model were evaluated. The 

 finite-difference models (Reid and Bodine 1968, Chen and Hembree 1977) will 

 not be discussed here because they are considered old technology compared with 

 present-day one- and two-dimensional modeling capabilities. 



132. The data employed as the test case were field measurements made in 

 September 1969. Masonboro Inlet was also studied under the Sea Grant Program 

 by Amein (1975) employing field data collected in 1974, using a predecessor 

 model to DYNLETl. 



Masonboro Inlet 



133. The basic features of Masonboro Inlet are shown in Figure 7. The 

 entrance to the inlet from the sea is protected by a jetty. During flood 

 tide, the flow enters Banks Channel to the east, Masonboro Channel to the 

 west, and Shinn Creek to the north. Thus, the system consists of a network of 

 channels, and there is no actual bay. 



134. All previous modeling efforts have had difficulty using the 

 September 1969 tidal elevations in the interior inlet channels for boundary 

 conditions. There is an apparent discrepancy in the data; for example, the 

 water level in some channels is consistently lower than the sea during part of 

 the ebb cycle. The source of the discrepancy could be unquantified wind 

 effects, shifts in the reference datum, or some other (unknown) reason. 



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