14 



BULLETIN 190, U. S. DEPARTMENT OF AGEICULTUEE. 



should be installed. Figure 6 illustrates such an automatic regulating 

 check for use in a channel having a normal capacity of 8 second-feet, 



Fig. 7. — A canal in semifluid soil: a, before eunetting; &, after cunetting. 



which will handle a discharge of 240 second-feet without danger of 

 erosion. 



