362 



ENGINEERING ON THE FARM 



well by the splash of the water every time a pail is drawn. 

 Each rain carries a large quantity of it from the cover and 

 surrounding soil into the well, through both the top and the 



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After University of Minnesota 



Fig. 283. In ordinary soil a drain tile laid 3 to 4 feet deep will drain from 



50 to 100 feet on either side, and as the depth of the tile is increased the 



width of the drainage area is also increased. An open well will act on 



the surrounding area the same as a drain tile. Consequently water 



leaching through piles of filth lying within this drainage area will 



quickly find its way into the well as indicated by the arrows. 



open wall, thus making an easy method of carrying into the 

 well disease germs which have been permitted to collect in 

 the vicinity. 



The source of pollution of most wells is from direct seepage 

 or leakage from privy vaults, barnyards, and directly through 

 the curbing and covering. The protection from the privy 

 vault may be accomplished most simply by maintenance of 

 a distance of at least 150 feet between the vault and the well. 

 Protection against surface leakage may be secured by means 

 of grading up around the well 8 to 12 inches with a radius 

 of 10 to 15 feet, using a hard, impervious clay, and then 

 building a concrete slab which allows of no direct leakage of 

 spilled water and rain back into the well. 



Shallow wells. The well should be located on land higher 

 than the barn and outbuildings, and as far from them as 

 practicable, to prevent water after heavy rains from flow- 

 ing either over the surface or through the soil toward 



