S r Specific gravity of berm stone relative to the water in which structure 

 resides 



S t Ultimate total scour depth at vertical piles 



SS 10 Suspended sediment concentration at 10-cm elevation above bed 



SWL Still-water level 



t Time 



T Wave period 



T Deepwater wave period 



u Near-bottom maximum horizontal orbital velocity 



u Current velocity at top of pipeline 



u* Shear velocity = (r/p) 1/2 



u avg Average jet velocity through the scoured area under a pipeline 



u b Near-bottom current velocity 



u crit Orbital near-bottom critical horizontal velocity 



Ujj^ Near-bed maximum orbital velocity 



U Average flow velocity 



V Velocity 



V c Critical velocity 



V s Volume of a sediment grain 



W Weight of particle 



W a Mean weight of primary armor stones 



W on Unit weight of stones to be used in apron for toe protection 



W 50 Median weight of individual berm stone in lb £ 



X Distance from seawall from the point of wave breaking 



X b Distance from intersection of beach profile and mean sea level to 

 the point of wave breaking 



Xfl Dimensionless variable defined by Madsen and Grant (1976) 



X s Dimensionless location of seawall relative to intersection of mean sea 

 level and pre-scour beach profile 



Y M Dimensionless variable defined by Madsen and Grant (1976) 



Y Elevation above the bed 

 z Distance above bed 



Greek Letter symbols 



A Arbitrary height above bottom 



q Parameter used to parameterize scour at vertical piles 



or crit Empirically obtained coefficient for critical water depth calculation 



/9 Parameter used to parameterize scour at vertical piles 



p s Density of sediment grains 



p Fluid density 



w Sediment fall speed 



A3 



