Table 2 



Scour Prediction Methods For Various Scour Modes 



Scour Mode 



Recommended 

 Method 



Appropriate Equation(s) 



Remarks 



Vertical Piles 



Herbich et al 

 (1984) 



lOflJ-^J " -1-4071 ♦ 0.2667 log^fl 



Provides method for 

 estimating local and 

 general scour 



Submerged 

 Pipelines 



Chao and 

 Hennessy(1972) 



a (ll R > ) 



Provides order of 

 magnitude estimates 

 only 





i« p -« p ) ° { 2 KHJRJ* - 3 <VV * !• J 



Vertical Seawalls 



SPM (1984) 



S ma x/H < 1 



Some laboratory data 

 using regular waves 

 have exceeded this 

 rule 



Vertical Seawalls 



Fowler (1992) 



s 



Valid for cases where 



-0.011 < h„/L < 0.05 



and 



0.015 < H <0.04 



-jj£ = v/22.72 Vi + - 25 



Smaller Rubble 

 Mound Structures 

 in Shallow Water 



Rule of thumb 



S raa x/H * 1 



This has not been 

 proven for rubble - 

 mound structures, but 

 should be sufficient 

 for revetments and 

 shallow- water rubble - 

 mound groins 



Rubble -Mound 

 Structures in 

 Deep Water 



Markle (1989) 



Stability number 

 guidance is given for 

 toe berm and toe 

 buttressing stone de-' 

 sign for wave stability 

 only. 



No guidance for scour 

 depth estimation or 

 protection is yet 

 available 



53 



