SPRINGS 



but at times of rain considerable volumes of water descend along 

 the depression, covering the spring and washing into it all sorts of 

 refuse from the hillsides above. Figure 1 1 shows another spring, 

 located in Missouri, receiving the drainage from a cornfield, to- 

 gether with such manure or other fertilizer as may be used in the 

 cultivation of the crops. This water, which carries both sulphur 

 and Epsom salts, is considered of medicinal value, but it is clear 

 that, situated as it is, its safety is at least doubtful. 



FIG. 12. Polluted spring in center of city street. (Photo by U. S. Geological Survey.) 



In general, it is not advisable to use springs for drinking 

 water where their location normally exposes them to inflows of 

 surface drainage. If other sources are not available, however, the 

 spring should be carefully protected by impervious walls, which 

 should be carried to sufficient height to keep out the surface water. 



Another source of frequent and objectionable though not 

 necessarily dangerous contamination is the leaves, paper, dust 

 and dirt blown into open springs by the wind. 



