resulted from radioactive sand-tracer studies conducted by the Coastal Engi- 

 neering Research Center (CERC) (Duane, 1976; Schwartz, in preparation, 1980). 

 The CERC results were that the fine-grained sand tracer (which matched the off- 

 shore bed size) and the coarser tracer moved landward, and the very fine-grained 

 tracer moved alongshore and slightly offshore. Vernon (1965) showed that very 

 fine-grained sand moved shoreward but in a very diffuse pattern. 



In shallow water, but outside the breaker zone, waves alone probably cause 

 selective sorting. The result is a shoreward transport of coarser sediment due 

 to the asymmetry of orbital flow (Cornish, 1898; May, 1973; see discussion of 

 null-point concept by Komar, 1976a) . Many laboratory and field studies indicate 

 that in the nearshore zone, transport of relatively coarse sand is commonly 

 landward. Some wave tank experiments show that beach accretion and nearshore 

 erosion are generally associated with low waves, long wave periods, and coarser 

 sand sizes (King and Williams, 1949; Rector, 1954; Scott; 1954, Sunamura and 

 Horikawa, 1974) . Alternatively, beach erosion and nearshore accretion are asso- 

 ciated with high waves, short wave periods, and finer sand sizes. This is in ac- 

 cordance with field observations indicating that beach profiles generally accrete 

 during fair-weather periods (swell conditions) and erode during storm periods 

 (Skepard and LaFond, 1940; Shepard, 1950; Bascom, 1951; Inman and Rusnak, 1956; 

 Gorsline, 1966; Nordstrom and Inman, 1975). As an example, in southern Cali- 

 fornia sand transported offshore during the winter seasonal change was deposited 

 as a sheet between 3- to 9-meter water depths (Nordstrom and Inman, 1975) . In 

 response to following summer swell conditions, beach accretion resulted from a 

 progressive onshore migration of sand from water depths of less than 10 meters. 



One aspect of storm transport pertinent to sediment placement is that with 

 storm waves the sand within the surf zone is transported seaward toward the 

 breaker zone, whereas sand seaward of the breaker zone continues to move shore- 

 ward (King and Williams, 1949; King, 1972). Some workers contend that this con- 

 vergence of transport may result in the formation of a storm bar (King and 

 Williams, 1949; Komar, 1976a). This is pertinent to sediment placement; if the 

 sand is moved seaward during mild storms to form a storm bar, water depths for 

 the storm bar should be relatively shallow and therefore allow for onshore move- 

 ment of material during ensuing swell conditions. Also, if placement is in 

 relatively shallow water but seaward of storm breakpoint position, disposal 

 sediment may move onshore, as desired, even during storm conditions. 



In view of theoretical, laboratory, and field data, it is likely that sand 

 placed in relatively shallow water outside the surf zone could undergo landward 

 transport into the surf zone. The probability of shoreward transport would be 

 maximized by placing material as shallow as possible to take advantage of mass 

 transport effects, by placing material during the onset of fair-weather condi- 

 tions (i.e., long wave period, low wave height, and usually offshore winds), and 

 by placing sand-sized material that is coarser than the native material at the 

 disposal site. 



4. Other Offshore Nourishment Experiments . 



Laboratory and field experiments in placing sand seaward of the breaker zone 

 have been conducted to examine the concept of offshore nourishment. Particularly 

 successful was a two-dimensional laboratory study which simulated small and large 

 storm conditions of the Great Lakes wave climate (Kamphuis and Bridgeman, 1975). 

 Relatively coarse sand (median size = 0.6 millimeter), which was placed 



