54 



BULLETIN 194, tJ. S. DEPARTMENT OF AGRICULTURE. 



6 stops, Up to 0.3, or 30 feet per hundred. Third. For very rough 

 materials, for earth channels and for cobble-bottom ditches (fig. 8). 

 The values of n range from 0.015 to 0.030 while the slopes cover aU 

 ranges likely to be encountered. On this chart the values of n cover 



In r\> i» 4:^ yi (7^ -nI 



R^Hvdrauilc Radius. 



I I 1 I 1 1 1 1 1 



¥ 



I I ] 



Fig. 5. 



I I I I I I I 11 11 111 1 1 ' I ' I I I ' 



Depth of Channel, in feet. 



-Areas, io square feet; hydraulic radii, in feet and hydraulic economic dimensions 

 (broken line) for channels having side slopes of IJ to 1. 



such a wide range that the guide Imes through any particular zone 

 have not quite the same slant, but the results obtainable from any 

 of these charts are more accurate than the agreement between pre- 

 liminary figures and results of tests made after construction. 



