254 



ENGINEERING ON THE FARM 



are thrown up with a plow down the line of the general slope, 

 from 20 to 30 feet apart. The water is permitted to flow 

 between these ridges, one after another. In this way the 

 water is under control and does not spread to such an 

 extent as in wild flooding. Where the supply ditch is small, 

 it is more satisfactory than the former method of flooding. 



After Irrigation Investigations, U. S. Dept. Agri. 



Fig. 209. Border irrigation. These borders have excessive length 



and width. 



Check method. The check method (Fig. 211) is also used 

 for the irrigation of grass, cereals, sugar beets, and similar 

 crops. In this method the field is divided into a system of 

 checks or compartments, each check being comparatively 

 level, with small ridges on all sides. The supply ditch flows 

 down a ridge and is permitted to enter the check through 

 an opening in the bank of the ditch or by means of a dam 

 placed in the supply ditch, the side above the dam being 

 cut out with a shovel. As soon as a check has received the 

 proper quantity of water, the flow is stopped and the water 

 is turned into the next check. When the checks are in the 

 form of squares or rectangles, they are known as rectangular 



