DRAINAGE INVESTIGATIONS. 41 



farm land consists mainly in designing tile-drainage systems and 

 outlet ditches and in supervising their construction. The classi- 

 fication swamp and marsh lands includes those areas which are per- 

 manently or periodically too wet for cultivation, due either to entire 

 lack of outlet, to inefficiency of outlet, or to tidal encroachment. In 

 this class are the tidal marshes along the Atlantic and Gulf coasts, 

 and by far the greater part of the enormous undeveloped swamp 

 areas of the Southern States. The reclamation of OA^erflowed land 

 presents intricate problems calling for the highest engineering judg- 

 ment to determine the maximum rate of run-off, the economical sizes 

 of channels, the proper location and dimensions of levees, and the 

 best arrangement for the interior drainage system. The continued 

 irrigation of lands in the arid region has resulted in the injur}'^ of a 

 very considerable part of those lands by seepage water and the con- 

 centration of alkali on or near the ground surface. The drainage 

 problems are peculiar to the irrigated region, their solution requir- 

 ing special study and no little experience in interpreting the effect 

 of subsurface conditions upon the movement of the ground water. 



The collection of technical data relating to drainage is an im- 

 portant part of the work of drainage investigations. A knowledge 

 of the relation of run-off to rainfall, topogi-aphy, and vegetation is 

 of basic importance in the design of adequate and economical drain- 

 age works, yet very few data on this subject are at present available. 

 Considerable work has been done along this line during the year. 



Investigations have also been made of the special problems of 

 pumping for drainage and of tidal marsh reclamation, and some ex- 

 periments have been made to determine the practicability of using 

 explosives in the construction of ditches. 



C. G. Elliott was in charge of drainage investigations, and all 

 work was done under his direction. 



IMPROVEMENT OF FARM LANDS. 



O. G. Baxter made a survey and plans for drainage on the Arkan- 

 sas State Penitentiary farm in Lincoln County, Ark. The entire 

 farm was surveyed, but detailed plans were prepared for under- 

 draining only a 32-acre experimental tract. 



Plans were made b}?^ J. R. Haswell for the tile drainage of a por- 

 tion of the farm owned by Judge Max L. McRae, in Telfair County, 

 Ga. The farm consists of about 1,400 acres, of which 375 acres are 

 in cultivation. 



On the farm of the Bureau of Animal Industry, United States 

 Department of Agriculture, near Beltsville, Md., S. H. McCrory 

 surveyed a poorly drained area and laid out a system of underdrains. 

 Plans were made for laying about 10,000 feet of tile to drain about 

 50 acres. 



