CHAPTER XXXV 



THE WATER PROBLEM OF A LARGE CITY 



IT is by no means unusual for the residents of a large city 

 or town to receive through the newspapers a notification that 

 the city water supply is running low and that economy should 

 be exercised in its use. The problem of supplying a large city 

 with an abundance of pure water is among the most difficult 

 tasks which city officials have to perform, and is little under- 

 stood or appreciated by the average citizen. 



Intense interest in personal and domestic affairs is natural, 

 but every citizen, rich or poor, should have an interest in civic 

 affairs as well, and there is no better or more important place 

 to begin than with the water supply. 



Where does your city obtain its water ? Does it bring water 

 to its reservoirs in the most economic way possible, and is there 

 any legitimate excuse for the scarcity of water which many 

 communities face in dry seasons ? 



Two possibilities. Sometimes a city is fortunate enough to 

 be situated near hills and mountains through which streams 

 flow, and in that case the water prcblem is simple. All 

 that is necessary is to run pipes, usually underground, from 

 the elevated lakes or streams to individual houses, or to 

 common reservoirs from which it may be distributed to the 

 various buildings. 



Figure 204 illustrates in a simple way how a mountain lake 

 may supply the inhabitants of a valley. Such a system of 

 water distribution is known as the gravity system. The nearer 



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