THE IRRl GA TWN AG E. 1 53 



ing gates are placed, by which the size of aperture from the main 

 canal is regulated and the flow of water therefrom controlled. Where 

 considerable accuracy of results is attempted, there is also placed in 

 the lateral ditch below the regulating gates a weir whose flow for all 

 depths is computed and tabulated, and for the purpose of determining 

 the depth at any time a graduation scale is so placed with reference 

 to the weir that the depth can be conveniently and accurately read 

 off. When it is desired to deliver into a lateral, so arranged, a given 

 volume of water, it is merely necessary for the ditch rider to consult 

 his weir tables and find the depth over this weir necessary to dis- 

 charge the required amount. He then increases or lessens the open- 

 ing from the main canal by moving the sliding gate in the regulating 

 structure until the required depth over the weir is realized. This is 

 the most important duty of the ditch rider, and for its proper execu- 

 tion he is expected to make a trip daily over the entire canal, or 

 his division of it, and to examine and regulate the gate of every con- 

 sumer. He usually travels on horseback or in a two- wheeled cart, and 

 carries a shovel, a hatchet, a small sharp-pointed bar, and frequently 

 a number of empty sacks. The hatchet is used to repair structures 

 and nail on boards which may have become loosened; the bar is for 

 raising gates which may be difficult to move by hand; and the shovel 

 and sacks are frequently required for the repair of banks and the 

 stoppage of holes caused by the work of gophers, muskrats, and other 

 burrowing animals, whose depredations frequently result in serious 

 and expensive breaks in the embankments. The holes thus mad*} are 

 usually small and insignificant at first, but become rapidly enlarged 

 through the erosion of the escaping waters, and if not stopped event- 

 ually result in a breach carrying away a portion of the embankment. 

 The ditch rider, however, is expected to inspect the whole works un- 

 der his charge daily, and usually detects the leaks by means of the 

 escaping waters before serious results ensue. Upon the discovery of 

 a leak thus caused, his first efforts are directed to the location of the 

 point on the inside of the bank at which the' water enters the hole. 

 This is frequently detected through the eddy or vortex appearing at 

 or near the opening. Having located this point, the orifice, if small, 

 can be closed by pushing into the hole one or two empty sacks; if al 

 ready too large to be closed in this manner, it can usually be accom- 

 plished by first filling a few sacks a half or a third full of loose earth 

 and ramming them into the mouth of the opening into which the water 

 from the ditch is passing. In this manner holes of considerable size 

 can usually be effectually stopped in a few minutes. 



The regulating gates before mentioned are frequently kept locked, 

 as already stated, and the key thereto carried by the ditch rider. 

 When, as frequently occurs, a water consumer has completed his irri- 



