52 IRRIGATION FARMING. 



bank, or laid to posts set in the bank. The steeper the 

 bank the greater, of course, will be the displacement of 

 the earth by water's action. In Figure 10 is seen a 

 canal on a hillside. 



Headgates. The best mechanical effort in build- 

 ing a canal should be expended on the headgate. This 

 should be located within a few hundred feet of the in- 



FIG. 11. HEADGATE OF A CANAL. 



take at the river with a fore bay of only moderate grade 

 intervening. The old-fashioned headgates were built of 

 lumber and were not usually sufficient to withstand the 

 tearing force of freshets in the stream. Iron gates came 

 later and were fairly successful in withstanding the 

 attacks of storms, but they often caused more seriu< 

 damage to the lower bank of the fore bay and oftentimes 

 led to its entire destruction. The gate should be 



