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Stoppage of a Sewer Line by Roots of Acer Saccharum. 



F. M. Andrews — Indiana University. 



The many well-known examples of stoppage of sewer and pipe lines 

 is probably exceeded from the standpoint of time, at least, by the fol- 

 lowing example: 



A six-inch sewer pipe line was laid five feet deep between two 

 trees of Acer saccharum. For two years the line remained perfectly 

 clear of all obstruction and no difiicutly was experienced. Late in the 

 summer of the third year a stoppage of this line suddenly occurred. 

 The trees above referred to are 21 years old, about 6 inches in diameter 

 and about 50 feet high and are vigorous specimens. They stand on a 

 west exposure and on a bank in the open where they are subjected to 

 the direct I'ays of the sun. The bank was a narrow one, so that the 

 ground was quickly dried out and the most actively growing part was 

 excessively dry. This caused the roots to grow down very quickly in 

 search of water and to escape the upper and lateral very dry layers of 

 the soil. On nearing the pipes there was also a chemotactic attraction 

 exerted. The roots finding a small opening grew in quickly, effecting a 

 complete closure of the tile line for a distance of fifteen feet. By their 

 further quick growth, especially after entrance, the heavy cement joints 

 were completely ruptured. The sewer line was replaced in the region 

 affected by heavy double-hub cast-iron pipe whose joints were sealed 

 with lead. Within the space of a few months, therefore, the roots of 

 these trees had completely blocked the pipes. The universally known 

 tendency of Populus deltoides as well as the roots of other trees and 

 plants to grovv^ into sewer and water pipes is common knowledge. The 

 location of the stoppage in a sewer line may be ascertained with com- 

 parative accuracy. This can be easily done, since one can ascertain the 

 volume of a given section of the pipe and the metered volume of water 

 required to fill the pipe fi-om stoppage to the water supply, due con- 

 sideration of course to be paid to those cases in which the stoppage may 

 not be complete and where some water may pass through. 



