PART IV: LONG-TERM SHORELINE CHANGE 
Introduction 
78. A central task of this study was to develop a numerical model for 
simulating long-term shoreline change along Sea Bright to Ocean Township and 
to apply the model to evaluate alternative plans for protective beachfill 
configurations. For an open-ocean coast, where wave action typically is the 
dominant factor producing sediment (sand) movement, shoreline change occurring 
in the time frame of several years or decades is believed to be controlled by 
the transport of sediment alongshore. The basic budget analysis technique 
commonly used in coastal engineering and geology is an arithmetic balance of 
beach volume changes with inputs and outflows of sediment at the landward, 
seaward, and lateral boundaries of the region considered. Regardless of the 
quantity of sediment gained or lost at the onshore and offshore boundaries of 
the study area, it is the longshore transport of sediment that ultimately 
determines the long-term plan shape (horizontal pattern) of the beach. A 
numerical model of shoreline evolution is a highly systemized and quantified 
implementation of the budget analysis method, in which the change in beach 
volume is calculated as a function of the time-varying wave conditions. 
79. As discussed in Part II, the budget study of Caldwell (1966) as 
well as subsequent studies have concluded that longshore sediment transport is 
the dominant process controlling long-term shoreline evolution of the north 
New Jersey coast. A numerical model of shoreline change for the project area 
is expected to be a valid extension of previous work, providing a useful tool 
for examining the course of beach change resulting from proposed shore protec- 
tion projects. 
80. Structure of this chapter. An introduction to the shoreline change 
numerical model is first given. Representation of structures in the model is 
discussed in some detail since a long seawall and numerous groins figure prom- 
inently in shore protection along this coast. The position of the shoreline 
is to a significant extent constrained by these coastal structures. Calibra- 
tion and verification procedures are then presented. 
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