56. Davis and Fox (1972) and Fox and Davis (1973) developed a concep- 

 tual model of beach change by relating changes to barometric pressure. They 

 reproduced complex nearshore features by schematizing the beach shape and 

 using empirical relationships formed with geometric parameters describing the 

 profile. Davis et al . (1972) compared development of ridge and runnel systems 

 (King and Williams 1949) in Lake Michigan and off the coast of northern Mas- 

 sachusetts where large tidal variations prevailed. The tides only affected 

 the rate at which onshore migration of ridges occurred and not the sediment 

 sequence that accumulated as ridges. 



57. Dean (1973) assumed suspended load to be the dominant mode of 

 transport in most surf zones and derived on physical grounds the dimensionless 

 fall speed as governing parameter. Sand grains suspended by the breaking 

 waves would be transported onshore or offshore depending on the relation 

 between the fall speed of the grains and the wave period. A criterion for 

 predicting the cross -shore transport direction based on the nondimensional 

 quantities of deepwater wave steepness and fall speed divided by wave period 

 and acceleration of gravity (fall speed parameter) was proposed. The criter- 

 ion of transport direction was also used for predicting profile response 

 (normal or storm profile). 



58. Carter, Liu, and Mei (1973) suggested that longshore bars could be 

 generated by standing waves and associated reversal of the mass transport in 

 the boundary layer, causing sand to accumulate at either nodes or antinodes of 

 the wave. In order for flow reversal to occur, significant reflection had to 

 be present. Lau and Travis (1973), and Short (1975a, b) discussed the same 

 mechanism for longshore bar formation. 



59. Hayden et al . (1975) analyzed beach profiles from the United States 

 Atlantic and gulf coasts to quantify profile shapes. Eigenvector analysis was 

 used as a powerful tool to obtain characteristic shapes in time and space. 



The first three eigenvectors explained a major part of the variance and were 

 given the physical interpretation of being related to bar and trough morphol- 

 ogy. The number of bars present on a profile showed no dependence on profile 

 slope, but an inverse relationship between slopes in the inshore and offshore 

 was noted. 



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