THE IRRIGATION AGE. 



69 



ditch, it is not necessary to follow the stakes closely in the bends. The 

 ditch will be better for being straightened a little, which may be done 

 by going above the stakes that locate the bends nearest the stream 

 and below the stakes farthest away. If the ground slopes very much 

 across the ditch line the stakes must be followed closely. After the 

 line is marked, two or three furrows are plowed, all being turned to 

 the lower side. A farm ditch can be made almost wholly with an or- 

 dinary plow by going over the line a number of times. The loose 

 earth in the bottom of the ditch may be removed with a scraper or 

 shovels. 



A small stream can be easily diverted into a ditch, if it is running 

 in a shallow bed, by a cross-stream dam of posts and plank, of posts 

 and brush, of brush and rock or cobbles, etc. (fig. 3). Such structures 

 are not usually water-tight, but they will raise the water to the level 



FIG. 5. Details of a headgate. 



of outflow into the ditch which is to carry it to the land to be irrigated 

 or to the reservoir (fig. 4) from which it is to be distributed. A better 

 dam, either of masonry or of earth, made water-tight by a puddle bar 

 of clay, may last for a long time in a small stream if adequate ar- 

 rangements are made for the passage of waste and flood water. 



Raising a small stream in a deep bed requires a dam of greater 



