o 



Pump 



ACP 



sand 



+ 

 water 



1 OBS#53 



Figure 10-2. ACP calibration tank 



where 



A = overall system constant including backscatter coefficient for 



the suspended sediment 

 C(z) = suspended sediment concentration at distance z from the 



ACP 

 V(z) = backscattered intensity signal associated with the distance z 



from the ACP 

 ifci = attenuation coefficient associated with the absorption by 



water and wash load 

 &2 = attenuation coefficient associated with the scattering by 



suspended sediment particles 



For uniform concentration, Equation 10-2 becomes the following simpler 

 equation 



AC = V(z) 2 exp^ + k 2 C)z] 



(10-3) 



The calibration constants, A, k u and fc, are determined by taking the loga- 

 rithm of Equation 10-3, solving for V(z), and applying linear regression as 

 follows: 



Chapter 10 Intermittent Near-Bed Sediment Suspension 



193 



