14 
BULLETIN 190, U. S. DEPARTMENT OF AGRICULTURE. 
should be installed. Figure 6 illustrates such an automatic regulating 
check for use in a channel having a normal capacity of 8 second-feet, 
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Fig. 7.— A canal in semifluid soil: a, before cunetting; b, after cunetting. 
which will handle a discharge of 240 second-feet without danger of 
erosion. 
