SYMBOLS AND DEFINITIONS--Continued 
loss of sand by wind 
sand discharge in a direction perpendicular to the beach 
average bottom slope to depth of no motion 
horizontal displacement at depth, D characterizing slope variation 
GQ? 
shoreline 
wave period 
time 
volume of sand over a stretch of shoreline, Ax, unity 
shoreline coordinates 
dimensionless shoreline 
deepwater limit of the beach 
function of x, y, t defining the bottom topography 
shoreline elevation above a datum z = o 
iD 
158 08) SLi 
deepwater wave angle with the ox-axis 
angle of breaking with the shoreline 
deepwater wave angle with the shoreline 
angle of the beach limit with the ox-axis in front of a groin 
horizontal displacement of the beach profile during time, dt 
function characterizing beach-slope variation as function of x 
function characterizing beach-slope variation as function of t 
function characterizing beach-slope variation with time due to rapid 
change of sea level 
function characterizing beach-slope variation with time due to manmade 
structures such as groin or navigation works 
a symptotic (in axium) value of Ay) when t > 
variation of wave direction by diffraction 
angle of wave ray with a perpendicular to shore in a diffraction zone 
water density 
