where 



V = volume of sand stored in the ebb shoal in (yd 3 ) 

 P = tidal prism in (ft 3 ) 



a,b = correlation constants 



Linear regression was used to find b for each of the groups and for all inlets combined. 

 Because there was no significant difference in the exponential correlation coefficients, the value 

 of b was set to 1 .23 (corresponding to the highly exposed coast) primarily because there was a 

 minimum of scatter for the Pacific coast inlets. Using b = 1.23, the correlation coefficient a was 

 determined for each group based on respective inlet prism - ebb shoal volume relationships. The 

 resulting equations for each condition are: 



V = 8.7xia 5 P 123 (highly exposed coasts) (3) 



V = 10.5 x 10 5 P 123 (moderately exposed coasts) (4) 



V = 13.8 x W 5 P 123 (mildly exposed coasts) (5) 



V = 10.7 x 10 s P'- 23 (all inlets) (6) 



Though Shinnecock Inlet is located on the somewhat more active northern mid-Atlantic 

 coast, it is oriented in a generally east-west direction, thus limiting its open ocean exposure. To 

 determine the stage of equilibrium development of the ebb shoal at Shinnecock Inlet, either the 

 moderately exposed or mildly exposed relationship should be most appropriate. Tidal current 

 measurements and calculations determined that the normal tidal prism for Shinnecock Inlet was 

 2.43xl0 7 m 3 (see Table 8). A probable maximum equilibrium ebb shoal volume can be 

 estimated by using the tidal prism from a spring tide condition (i.e., 3.31xl0 7 m 3 or 

 3.85 x 10 7 m 3 ). Results from each of these calculations are given in Table 13. 



As discussed previously, the measured volume of sand in the ebb shoal is 6.4 million m 3 

 (8.4 million yd 3 ). According to the Walton and Adams (1976) relationships, the equilibrium 

 volume for the Shinnecock Inlet ebb shoal should be between 7.8 and 10.3 million m 3 (10.2 and 

 13.4 million yd 3 ), which means currently it has between 63 and 82 percent of its equilibrium 

 volume. A theoretical volumetric limit to the equilibrium volume can be predicted by examining 

 the spring tide equilibrium volumes, which range between 1 1.5 million and 18.1 million m 3 

 (15.0 million and 23.7 million yd 3 ), depending on the exposure of the coastline. 



Chapter 4 Design Criteria 49 



