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DOMESTIC WATER SUPPLIES FOR THE FARM 



constantly encountered, and the services of a professional driller 

 are usually essential. Detailed descriptions of the types of wells 

 and technical explanation of the drilling methods would, there- 

 fore, be of little value to the farm owner. 



The character of the different forms of deep wells are indicated 

 in the table on page 105, together with the conditions to which 

 they are best adapted. 



Advantages and Disadvantages of Different Types of Deep 

 Wells. All deep wells possess the advantage of drawing on 

 supplies that are usually far below the limits reached by pollu- 

 tion. The majority are cased through the surface soils and for 

 at least several feet into the rocks, which commonly prevents con- 

 tamination from shallow sources. Furthermore, the supplies, 

 though perhaps no greater than those of many relatively shallow 

 wells, are likely to be more steady and less affected by droughts. 



On the other hand, deep wells are expensive to drill and the 

 water is commonly more mineralized than that of shallow wells, 

 although the reverse is true in many of the alkaline regions of the 

 West, and also in localities where the shallow waters are from 

 clayey or marly materials while the deep supplies are from sandy 

 foundations. 



The special advantages and disadvantages of the individual 

 types are brought out in the accompanying tables. 



Summary of advantages and disadvantages of different types of deep wells. 

 Standard drilled wells. 



Advantages. 



Disadvantages. 



Adapted to all rocks. 



No ordinary limitation as to depth. 



Can be readily deepened. 



Little affected by droughts. 



Can utilize all water strata where there is no 



great difference in head if casing is perforated, 



but this is rarely done. 



Pollution is completely shut out if properly cased. 

 Can be located anywhere. 

 Gives fair records of materials and water beds 



encountered. 



Expensive; requires elaborate outfit, skilled labor, steam 

 power with the attendant charges, and costly casing and 

 pumps in deeper wells. 



Many difficulties in drilling; frequent losses of tools. 



Cleaned with difficulty. 



Slow response to rainfall; slight storage capacity. 



Corrosion of pipes and screens. 



Incrustation of pipes and screens. 



Entrance of sand through screens or clogging of screens. 



Taste of water due to solution of iron under certain condi- 

 tions. 



