should have a stable foreshore slope near 1 on 25 while 0.20-inillimeter 

 sand would have a stable slope of about 1 on 75. 



The variation in sand size with position across a profile (Fig' 16), 

 or at a profile through time (Fig. 18) can range about as widely as the 

 extremes between profile lines (Tables 2 and 3), indicating that even these 

 sand-size variations may have coastal engineering importance. For example, 

 samples collected from the surf zone may have as much as a 0.4-phi average 

 difference from samples from the berm (Fig. 16). Moreover, in two cases 

 (Ludlam Island and Atlantic City) the surf zone samples are coarser while 

 in the other case (Long Beach Island) surf zone samples are finer than 

 berm samples. Such data would be useful in evaluating the practice of 

 bulldozing sand onto the beach (usually illegal) used by some landowners. 

 In addition to direct influence on coastal engineering design, sand-size 

 variations are an important factor in determining the effect of coastal 

 processes along a coast, and thus may be of indirect importance to coastal 

 engineering as well. 



Figure 20 exhibits the positive and negative correlation among the 

 three beaches, using Atlantic City as a reference beach. For the sample 

 average versus elevation data (filled squares), sample correlation coef- 

 ficients were 0.92 between Atlantic City and Ludlam Island and -0.50 

 between Atlantic City and Long Beach Island. 



2. Southward Decrease in Size . 



From Figure IS, a general decrease in sample size is apparent from 

 north to south. Sample averages by locality (average column in Table 2) 

 show an orderly decrease in size from 1.58 phi (0.33 millimeter) at Long 

 Beach Island, through 1.91 phi (0.27 millimeter) at Atlantic City, to 

 2.14 phi (0.23 millimeter) at Ludlam Island. It has been observed that 

 this decrease is in the direction of net longshore sediment transport 

 (MacCarthy, 1931, p. 37; McMaster, 1954, p. 207), which is in accordance 

 with the hypothesis that size will decrease in the direction of transport, 

 since the coarser, heavier particles have a tendency to settle before the 

 finer particles. 



However, considering sand size for individual profile lines, there are 

 significant departures from this overall southward decrease in grain size. 

 At profile line 3 on Long Beach Island, sand size is somewhat finer than 

 would be expected (Fig. 15) from other profile lines on Long Beach Island. 

 However, this profile line is located about 600 feet south of the south 

 jetty which protects Barnegat Inlet (Fig. 3). The pair of jetties at this 

 inlet may form a sediment trap in the immediate vicinity of profile line 

 3 by protecting the beach from the tidal flow in and out of Barnegat Inlet, 

 as well as from longshore currents and waves from the northeast. This 

 would explain the finer sand size on the beach in this vicinity (Fig. 15). 



The largest deviation from the overall trend at a given locality in 

 sample set A occurs at profile line 2 in Atlantic City (Fig. 6), which is 



42 



