PART IV: EMPIRICAL AND PARAMETERIZED MODELS 



64. The earliest shoreline retreat model was proposed by Bruun (1962) 

 who postulated that the profile would rise and shift landward, without 

 changing shape, in response to a rising sea level. The Netherlands has 

 always been concerned with storm effects and dune erosion, and Edelman (1968, 

 1972) proposed the first dune erosion model based on a simple change in 

 profile slope and a balance of eroded to deposited material. Modified 

 Edelman approaches have been used by Vallianos (1975), Tetra Tech (1983), and 

 by Hill and Herchenroder (1985). 



65. Recent research efforts have resulted in two models which are 

 currently being used for engineering studies. Based on a series of large- 

 and small-scale laboratory tank tests, limited field data, and theoretical 

 work, the Dutch have improved and refined the Edelman approach (Vellinga 

 1983b, 1986 and van de Graaff 1983) and are using it in the design of 

 artificial dunes in The Netherlands. At nearly the same time, a numerical 

 model of beach and dune erosion based on the equilibrium profile equation was 

 developed by researchers at the University of Delaware and the University of 

 Florida and reported in a series of theses (Kriebel 1982 and Moore 1982), 

 papers (Kriebel and Dean 1985a, b and Kriebel 1986), and reports (Chiu and 

 Dean 1984 and Kriebel and Dean 1985c). The model has been widely used to 

 estimate dune erosion in Florida (Chiu and Dean 1984, Kriebel 1984a, b, and 

 Kriebel 1986). Both of these models, which will be referred to as the 

 "Vellinga" and "Kriebel" models, have been shown to produce reasonable dune 

 erosion estimates. A third model, the MSBWT model developed by Balsillie 

 (1984c), is also being used by the State of Florida for erosion estimates. 



In this section, these three models will be described, and the relative 

 merits of each will be discussed. 



The Vellinga Model 



66. Because much of their country is below MSL, the Dutch have long 

 considered the building of dikes, dunes, and other coastal structures of 

 primary importance. Vellinga (1983b, 1986) presents a complete discussion of 

 the most recent Dutch method. A probabilistic approach to dune design using 

 the model has been reported by van de Graaff (1983, 1986). Sargent and 



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