SOURCES OF IRRIGATION WATER 



39 



moisture. Relatively few gardens in the East are fully equipped 

 for the artificial watering of their entire areas. Chief dependence 

 is placed upon the rainfall to supply the moisture for producing 

 the crops. In eastern gardens rain is fundamental and irrigation 

 incidental. In the arid regions of the West, however, where rain- 

 fall is scarce during the growing season, irrigation is depended 

 upon to produce the crops and any summer rains that may occur 

 are purely incidental. In humid regions, irrigation is a problem 

 for the individual grower; in arid regions it is a problem for the 



Fig. 20. — Furrow irrigation of melons (cantaloupes) immediately following planting. 

 Rocky Ford, Colorado. 



entire country, for in many places no crops whatever in field or 

 garden can be produced without it. 



Sources of Irrigation Water. — Some of the sources of water 

 supply in irrigated regions are rivers fed from melting snow 

 through mountain streams, natural lakes at high elevation, arti- 

 ficial lakes or reservoirs for the storage of storm water, artesian 

 wells. Usually the water is conducted for long distances through 

 open ditches, flumes or conduits, before it reaches the land to be 

 irrigated. Whenever possible it is delivered by gravity, but some- 

 times pumping is necessary to raise the water to a point higher 

 than the land to be irrigated. 



