40 REPORT OF OFFICE OF EXPERIMENT STATIONS. 



sti-oams, has oxperiencod the need of definite knowledge upon this 

 subject. 



Drainage investigations of this Office undertake to collect the avail- 

 able information relating to agricultural drainage; to study the 

 practice of this and other countries, learning the causes of success and 

 of failure; to investigate the conditions allecting the design of drain- 

 age systems; and to use the information gained in this manner for en- 

 couraging the reclamation and improvement of wet lands. The Office 

 also disseminates information regarding the methods and benefits of 

 drainage, and assists landowners in devising plans for draining cer- 

 tain areas in order to test the value of such undertakings. The need 

 for such studies is emphasized by the increasing number of inquiries 

 received from every part of the United States and even from other 

 countries. Information is asked regarding the proper depth and 

 arrangement of underdrains and open ditches, the efficiency' of drains 

 in certain described soils, the efi'ect of drainage upon the soil and 

 upon crop production, and the methods and costs of construction. 

 Other inquiries relate to the computation of flow in natural water 

 courses and in artificial channels, the coefficients to be used in the 

 h3'draulic formulae, and the effect of bends, obstructions, and non- 

 uniform cross sections; also to the maintenance of ditches, the pre- 

 vention of silting and of erosion. There is much need of reliable 

 data concerning the amount of water that should be removed from 

 drainage areas, how this depth is related to rainfall and size of area, 

 and how it is affected by climate, soil, and topograph}^ Many re- 

 quests are made for personal examinations and for surveys, with defi- 

 nite plans for the work that may be found practicable. Assistance 

 is desired in the organization of drainage districts wdiere the cooper- 

 ation of many landowners is necessary, in assessing the costs against 

 property benefited, and in appraising damages, as well as in drafting 

 general drainage laws. 



Much information is given by correspondence, in reply to specific 

 inquiries. Sketches and maps are received, with descriptions of soil 

 and topography, from which drainage plans are outlined more or 

 less definitely by the Office engineers. P'requently from personal in- 

 spection of the lands the engineers are able to recommend the plans 

 to be followed and to make approximate estimates of the cost. 

 Where necessary, drainage surveys are made by field parties, and the 

 best plans of improvement worked out in detail. Plans prepared by 

 local engineers are frequently submitted for the criticism or ap- 

 proval of the Office. The exceptional experience of the department 

 engineers enables them many times to suggest changes that will make 

 the work planned more effective or more economical. 



The collection of data upon matters related to drainage is consid- 

 ered very important. A study is made of current drainage practice 



