establish various empirical coefficients. The approach considers both sus- 

 pended load and bed load. It is assumed that the rate of suspended load 

 transport is dependent upon the total shear on the bed. Therefore, the shear 

 velocity v* is the important velocity for suspended load transport. Bed 

 load transport, however, is assumed to depend upon the actual shear stress on 

 individual sediment grains. Ackers and White (1973) assume that this stress 

 is comparable with the shear stress that would occur on a plane granular sur- 

 face bed with the same mean stream velocity. Thus the mean velocity of flow 

 v is the important velocity for bed load transport. 



63. Considering only currents (not waves), Ackers and White (1973) 

 derived sediment transport rate in a dimensionless form. For convenience in 

 practical application, this may be written as: 



(1 - p) 



D — 



(F - A)'"l 



(82) 



A 1 



where 



S = total sediment transport rate per unit width (vertically 



integrated combined bed and suspended sediment load) (ft /sec/ft) 



D = sediment diameter which is exceeded in size by 65 percent (by 

 weight) of the total sample 



C = exp 



Y = D 



2.86 In Y - 0.4343 (In Y)' 



, 1/3 

 -(s - 1) 



- 8.128 



(83) 



(84) 



s = mass density of sediment relative to that of the fluid 

 = 1.0 - 0.2432 In Y 



(85) 



9.66 



+ 1.34 



(86) 



A = 



10 h 



3 ^g> ^ 



fg(s - 1)d1 



n^l 



0.23 

 „l/2 



+ 0.14 



(87) 



(88) 



= kinematic viscosity of fluid 



50 



