DRAINAGE OF WET LANDS OF SOUTHEEN LOUISIANA. 



41 



latter feature permitting tlie water to be lowered to the end of the pipe without 

 allowing the entrance of air. The saving in velocity head losses secured by- 

 enlarging the pipes amounts to nearly 2 feet, which is about one-half the usual 

 lift. The pipes are supported by steel hangers secured to pairs of round piling. 

 The pump is driven by a 14 by 16 inch vertical slide-valve engine, direct con- 

 nected to, the pump shaft with flexible coupling. This style of engine occupies 

 less floor space and also 'requires shorter lengths of pipes on the pumps than 

 does the horizontal type. In addition, it is less likely to cause vibration 

 or motion of the foundation when operated at high speed. Steam is fur- 

 nished by a return tubular boiler burning crude oil. The building for this 

 machinery has a timber frame covered with heavy corrugated galvanized iron. 

 The theoretical capacity of the completed plant, when both pumps are working 



Fig. 11. — Sketch plan and elevation of one unit in pumping plant of area No. 4, 



Raceland, La. 



most economically, will be 1 inch per day with a maximum of 1.4 inches per day. 

 One pump, with a capacity of 0.7 inch per day, successfully drained this tract 

 for nearly two years until the time of high water in December, 1911, and 

 January, 1912, when, owing to the seepage through the levee in addition to 

 the rainfall, the ground was flooded for two or three days. At this time the 

 reliability of this plant was shown, as the pump was operated continuously 

 for six days and nights. With the second unit installed, no trouble should 

 be experienced in removing any rainfall encountered, especially since the levees 

 are now much better able to keep out seepage. It is quite certain that when 

 all of the tract is under cultivation and all lateral ditches are in operation 

 the intensity and amount of the run-off will be largely increased, but, due to 

 the large reservoir capacity of the plant, no trouble should be encountered. 



25102°— Bull. 71—14 6 



