PECULIARITIES OF BEHAVIOR OF WELLS 



141 



Even if the well is not pumped, the air current, if long continued, 

 will eventually freeze the ground water at G and possibly also 

 the water in the pipe. 



The remedy for freezing in such a well is to fill tightly the space 

 between A and B at a point near the surface with some impervious 

 material. A filling of cement resting on an improvised plug will 

 probably effectively prevent freezing. The home-made rag pack- 

 ing sometimes used is generally too po- 

 rous, permitting enough air to get through 

 to produce freezing. Rubber plugs are 

 effective, but care should be taken not 

 to use materials which can damage the 

 water if they happen to drop to the bot- 

 tom of the well. Manure should never 

 be used about a well cased in the manner 

 shown in the figure, as it can get to the 

 water just as well as the air can. 



Figure 63 shows a well which, though 

 cased to a certain depth, has developed 

 leaks by corrosion or imperfect joints 

 and by careless setting of the casing in 

 the rock. During periods of high barom- 

 eter cold air enters the mouth of the well, 

 passes downward between the casing and 

 pump tube, and out into the porous 

 stratum. The constant indraft of cold FIG. 63. Conditions govern- 

 air quickly freezes the water remaining ^freezing in wdis with leaky 



* t casings and porous walls. 



in the pipe after pumping. 



The proper treatment is to plug effectually the space between 

 the two pipes at a point near the surface. 



The conditions in a well passing through porous rock are also 

 illustrated in Figure 63, in which the bed of sandstone, although stiff 

 enough to stand without casing, may be sufficiently porous to 

 permit large amounts of chilled air to enter from the well during 

 periods of high barometer, resulting in freezing, as before. The 



