226 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



priced and intensively cultivated crops throughout the humid region 

 will be insured against drought by supplemental irrigation. 



DRAINAGE INVESTIGATIONS. 



The drainage investigations of the Department of Agriculture are 

 destined to play no mean part in the development and conservation 

 of our natural resources. There are in the United States approxi- 

 mately 79,000,000 acres of land, exclusive of tidal marshes, that can 

 not be profitably cultivated on account of excess moisture. It has 

 been estimated that this area, comprising 52,665,000 acres continually 

 wet, 6,826,000 acres of wet grazing land, 1-1,748,000 acres periodically 

 overflowed, and 4,766,000 acres of farm land periodically swampy, 

 could be drained at a net profit of $1,594,000,000, measured by 

 increased land values, with an increase of annual income estimated 

 at $273,000,000. AVestern irrigated lands that but recently yielded 

 grain and fruit abundantly have been abandoned, having become 

 swampy or incrusted with alkali. The area a.ffected, already great, 

 is enlarging every year as irrigation continues. The lack of natural 

 drainage is requiring that artificial means be provided for removing 

 the excess water and preventing a large part of the lands under irriga- 

 tion from being rendered worthless. 



SCOPE. 



Previous to 1902 the department gave no special attention to land 

 drainage. Now the investigations embrace a study of the require- 

 ments of drainage in various localities and under differing condi- 

 tions; the collection of technical data of service to engineers and 

 others having to do with the design of drainage improvements; 

 and the rendering of assistance by correspondence to owners of 

 land needing drainage, by personal consultation and occasionally by 

 surveys with reports presenting detailed plans for the requisite im- 

 provements. The construction work, however, is done by the land- 

 owners to be benefited. Investigations have been conducted in nearly 

 every State. The total area surveyed is approximately 8,800,000 

 acres, classified as follows: Subject to periodical overflow, 4,110,000 

 acres; continually wet, 3,550,000 acres; requiring new or improved 

 outlet channels, 760,000 acres; farm lands needing complete drainage, 

 20,000 acres; irrigated lands, 360,000 acres. 



RESULTS. 



As the result of the department's work there has developed a very 

 active interest in the drainage of the swamps and other wet lands of 

 the coastal plain, from Maryland to Texas. Drainage engineers of 

 the Office of Experiment Stations have examined a large part of 

 those areas, preparing plans for more than half a million acres. 



