Bui. 854, U. S. Dept. of Agriculture. 



PLATE XII. 



Velocities in Feet per Second 



.5 .6 .7 .8 .9 1.0 1.5 2.0 2.5 3.0 4.0 5.0 6.0 70 8.0 9.0 



.0003 



•08 .10 .15 .20 .25 .30 40 .50 .60 



Mean Hydra u tic Radii in Feet 



Curves Used in the Derivation of a Formula Applying to Both Clay 

 and Concrete Tile. 



