CHANGES OF GRADE IN STRAIGHT CHANNELS 87 



channel conditions, as for all the other cases, but by the level of the 

 horizontal asymptote of the A2 curve. Computation of the discharge, 



_^^ ^ ^ ^ per A,,,, s^^ _ _ ^ ^ ^ ^ ^ ^ C*;rS^ 



Fig. 801. Water-surface Profiles over a Break in Grade, for Steady Flow in a 



Long Prismatic Channel. 



for a given elevation of the asymptote (or of the water level in a pool 

 at the upstream end of the curve), is different for profile {k) than for 



