232 



The Country House 



Well. 



a gravelly knoll or where the formation is such as to bring the water-bearing 

 stratum farther from the surface, the depth of 80 feet is often reached. 



In selecting a site for the well there are two sources of contamination to be 

 borne in mind, surface drainage and subsoil filtration. The ordinary hole in the 

 ground is very liable to become, under ordinary circumstances, a catch basin for 

 surface drainage, to say nothing of the impurities that find access to it through the 

 subsoil. For the above reasons it is absolutely necessary that the location of the 



well should be as far as possible from 

 barnyard, privies, cesspools and all other 

 possible sources of contamination, not 

 only your own but those of your neigh- 

 bours. Be sure, too, that the location 

 be in the uphill direction. Where the lot 

 of land is small or the buildings crowded 

 together, the well problem becomes a 

 most difficult and serious consideration. 

 Not only is it close to the local source of 

 contamination, but the extreme handi- 

 ness of the neighbour and his little prob- 

 lem makes this all the more complicated. 

 Simple filtration through permeable soil 

 will reduce a certain amount of impurity 

 for a limited time, but as the soil is soon 

 likely to become clogged and choked 

 with it, this is no absolute safeguard 

 from pollution. It is readily seen from 

 this why a good well may become suddenly affected from various causes which 

 may have been operating without apparent effect for years. 



As a rule, wells sunk in sand lying over an impervious stratum, especially clay, 

 if not of considerable depth do not afford much water. Often a fair quantity 

 may be obtained, but the quality is very apt to be bad. This is due in a measure 

 to the extreme porousness of the soil and its tendency to absorb surface water with 

 but little chance of effective filtration before it reaches the impervious stratum. 

 The best wells are those which are sunk through impervious strata to pervious 

 ones below. The water in quantity and quality is generally excellent. If such a 

 well is properly constructed, it should eliminate all chance of contamination from 

 surface water and many of the chances of menace from other sources. An 

 effective method of construction would be to lay the well below the impervious 

 stratum dry and the portion above and through the impervious strata in Portland 

 cement, carefully pointed inside and thoroughly plastered outside. To re-enforce 

 this a bank of clay may be added, care being taken to see that it is properly 

 "puddled," or, in other words, pure clay is filled into the trench about the well 

 in small pieces and in small quantities at a time. In the intervals the clay is 

 "puddled" by adding water, which tends to soften and reduce it to a solid, 

 compact mass. This bank of clay, together with the tight wall, will prevent 

 surface water from entering (see Fig. 43). 



Fig. 43. A sectional diagram showing i well dug through im- 

 pervious strata to pervious water-bearing strata below 



