276 



THE IRRIGATION AGE. 



THE IRRIGATION WELL 



THE irrigation well is 

 becoming a more 

 important factor in the 

 development of the arid 

 states each year. In 

 practically all the arid 

 districts there are under- 

 lying strata of water, 

 sufficient to irrigate the 

 lands above, providing 

 water from rivers or 

 creeks is not available 

 at a less cost. These 

 pumping districts are 

 being "discovered" in 

 the West almost every 

 week. A number of new 

 artesian belts have also 

 been opened up this year. 



There are two general types 

 of wells the open or dug well 

 and the drilled well. Often wells 

 are combinations of the two. 



The open well is used where 

 the water bearing stratum is close 

 to the surface. Such wells depend 

 for their supply on the inflow of 

 water from a large lateral area. 

 These wells are usually walled 

 with wood, iron, stone or con- 

 crete. 



Driven or drilled wells are 

 sunk where the water stratum is 

 at a considerable depth, but tilt- 

 ing strata which cap and underlie 

 the water zone may so carry the 

 water of a higher elevation that 

 the water level will be near the 

 surface in the well when com- 

 pleted, or it may form a flowing, 

 or artesian well. Persons accus- 

 tomed to open wells are often sur- 

 prised at the quantity of water 

 delivered by a deep drilled well of 

 only a few inches in diameter, c. ki 1 y'Ranch"a't'pen 

 This type of well depends for its puinp hoUK wat built 

 water supply on the depth to 

 which it is sunk in the water zone. Bored wells 

 are usually cased at the surface with iron pipe, the 

 piping generally extending to bed rock, but fre- 

 quently the entire depth of the well. When cased 

 the entire depth the lower part of the casing is 

 usually perforated to form a strainer. The per- 

 forated section of the pipe is sometimes as great as 

 90 feet in length, but usually is eight to 20 feet. 

 Sometimes wells are cased with solid pipe and the 

 strainer is attached to the suction pipe of the pump. 



The combination of dug and driven, or drilled, 

 well is used where it is desired to supplement the 

 flow of a water stratum near the surface with that 

 of a deeper water bearing 'zone, the head on the 

 lower stratum being such that it will raise the water 

 to the higher level. Wells of this type are also sunk 

 where some type of pump is to be used, the form 



Testing a pump in a New Mexican Ranch 



~j of which will not ad- 

 mit of its being in- 

 stalled in a small tubular 

 drill hole and it is de- 

 sired to place the pump 

 as near the water sup- 

 ply level as possible. In 

 this case the pump is 

 placed in an open pit 

 near the water level and 

 its suction pipe extends 

 down into the drill hole. 

 No general recom- 

 mendation can be given 

 as to the most desirable 

 type of well, as the 

 depths at which water 

 can be obtained vary 

 greatly in different lo- 

 calities and it should also be 

 taken into consideration whether 

 water is desired for irrigation 

 only or is to be used for drinking 

 purposes in addition to furnishing 

 the irrigation supply. 



Open wells always receive their 

 water supply from surface leach- 

 ings containing more or less dis- 

 ease germs and filth, and water 

 from such wells should never be 

 drunk. It is estimated that 90 

 per cent of all fevers in rural dis- 

 tricts are directly due to drinking 

 water from open wells. A driven 

 or drilled well is always cased 

 with iron pipe to bed-rock and 

 if the piping is driven tightly into 

 the rock all surface leachings are 

 excluded and the supply must 

 come from below protected by an 

 overcapping rock formation and 

 filtered through a deep sand or 

 gravel stratum which precludes 

 the possibility of its becoming 

 contaminated with disease germs 

 and filth. 



If wells are to be sunk only for 



irrigation purposes there is to consider only the 

 depth at which a sufficient supply of water can be 

 procured and the form of pump that is to be used 

 in pumping. It is important, however, that the 

 most economical style of pump for the locality 

 be considered when putting down the well, as cost 

 of pumping is the principal element in determining 

 the economy of the installation. Usually the kind 

 of well that will admit of the use of the most effi- 

 cient pump should be sunk. 



In most localities the approximate depth at 

 which water is found is already known by the depth 

 of existing wells in the vicinity or by the geological 

 formation. In sinking a well, however, the quantity 

 of water it is to supply must be considered, as 

 it frequently occurs that a small water-bearing 

 stratum near the surface will prove adequate for 



