deep water, there is not yet any evidence that significant amounts of infra- 

 gravity energy are derived from this source. 



21 . A schematic breakdown of both the free and bounded infragravity 

 long waves that contribute to infragravity motions in the nearshore of a slop- 

 ing beach is shown in Figure 5. Both leaky and edge waves produce standing 

 long waves in the surf zone. There is also the possibility that bounded long 

 waves could be partially phase locked to seaward propagating leaky waves and 

 generate a standing wave seaward of the surf zone. The diagrammed placement 

 of these waves in and out of the surf zone is suggested by both observations 

 and proposed generation mechanisms. 



(REFLECTED LEAKY WAVES) 

 STANDING WAVES 



LEAKY WAVES OUT 



EDGE WAVE MODE 





BOUNDED LONG WAVES IN 



Figure 5. Schematic diagram of long waves on sloping beaches, 

 with the top three lines representing free waves and the 

 bottom line representing the phase-locked wave 



Infragravity Energy and Sediment Transport 



22. Infragravity energy contributes a substantial portion to the total 

 shallow-water elevation and current variance in the nearshore (Emery and Gale 

 1951; Inman 1968a, b; Suhayda 1972, 1974; Sonu, Pettigrew, and Fredricks 1974; 

 Goda 1975; Huntley and Bowen 1975; Sasaki and Horikawa 1975, 1978; Saski , 

 Horikawa, and Hotta 1976; Huntley 1976; Wright, Thorn, and Chappel 1978; Wright 

 et al. 1979; Wright, Guza, and Short 1982; Bradshaw 1980; Holman 1981; Holman 



15 



