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LAND DRAINAGE 



Land drainage ^ is the process of withdrawing from the 

 soil the superfluous or gravitational water occurring in 

 the larger spaces within the normal root zone. Excess 

 moisture in the soil interferes with ventilation, keeps 

 down the temperature, and seriously disturbs the physical 

 nature of the soil. Any means that permits the free flow 

 from the soil of the gravitational water affords drainage. 

 Many methods are used, according to circumstances. 

 Indications of the need of drainage are the presence of 

 free water in the surface soil and in excavations into the 



1 Elliott, C. G. Engineering for Land Drainage. New 

 York. 1912. 



Faure, L. Drainage et Assainissement Agrieole des Terres. 

 Paris. 1903. 



Eang, P. H. Irrigation and Drainage, Part II. New York. 

 (Revised edition. 1909.) 



Klippart, J. H. Principles and Practice of Land Drainage. 

 Cincinnati. 1894. 



Woodward, S. M. Land Drainage by Means of Pumps. 

 U. S. D. A., Office Exp. Sta., Bui. No. 243. 1911. 



Warren, G. M. Tidal IMarshes and their Reclamation. 

 U. S. D. A., Office Exp. Sta,, Bui. No. 240. 1911. 



Elliott, C. G. Drainage of Farm Lands. U. S. D. A., 

 Farmers' Bui. No. 187. 1904. 



Miles, M. Land Drainage. New York. 1897. 



See also the following bulletins of state experiment stations : 

 Michigan, Sp. 56; Maryland, 186; New York (Cornell), 254; 

 Utah, 123; Wisconsin, 138, 199, 229; Ontario, Canada, 174, 

 175, 



627 



