196 The National Geographic Magazine 



RECLAIMED SHIOCTON SWAMP, WISCONSIN — A CROP SAID TO BE 20 TONS PER ACRE 



fore any great project of wet land rec- 

 lamation is far above the plane of mere 

 local ditching. If such work is to be 

 prosecuted intelligently and purposefully, 

 the actual construction must be preceded 

 by topographic surveys, measurement of 

 stream flow, consideration of necessary 

 capacity of channels, and other physical 

 studies. The actual development itself 

 can be carried out only by a corps of com- 

 petent engineers. In this connection Mr 

 Garfield points out the danger of ex- 

 tensive drainage undertakings without a 

 full consideration of all the factors. 

 Swamps are in a way natural storage 

 reservoirs, and they give off their waters 

 slowly, and if large areas are drained it 

 means that there will result a quicker 

 run-off from the drainage basin, and the 

 question must be considered whether the 

 channel capacity of the natural arteries 

 is sufficient to carry the increased flow, 

 else the improvement of one reach of a 

 basin may result in the overflow and de- 

 struction of another reach lower down. 



The gauging of the streams in an area 

 considered for draining and the determi- 

 nation of their maximum carrying capac- 

 ity is therefore an essential part of the 

 preliminary investigation. The value of 

 figures of stream flow are much greater 

 when they have been continued over long 

 periods, and the work and records of 

 the Water Resources Branch of the 

 Geological Survey, which cover many 

 years past, are invaluable. 



One of the preeminent factors is the 

 determination of the value of the re- 

 claimed land. The crop it will best raise 

 will give actual figures upon which to 

 base estimates, and the careful attention 

 which the experts of the Department of 

 Agriculture are giving to soil surveys has 

 a most valuable application to the subject. 



An item for primary consideration is 

 the maintenance and extension of the 

 navigable waterways, which are directly 

 under the control of the engineers of the 

 U. S. Army. 



The amount of work to be done is 



