THE NATIONAL ASPECT OF SWAMP DRAINAGE 5 



In numerous places we are draining the upper portions of swamps with- 

 out providing suitable outlets for water in the lower portions. This process 

 not only makes the drainage works less effectual than they would otherwise 

 be, but it also accentuates the swamp conditions in the lands below. 



THE PROBLEM OF DRAINAGE 



Artificial drainage creates new conditions. In its natural state a 

 swamp gives up its water slowly. If that were not so, the land would not 

 be swamp land. The rivers draining that swamp are accustomed to receive 

 the water only at the rate at which the swamp gives it up, therefore thosis 

 rivers have through long ages become habituated to receive water at that 

 rate and at no greater rate. Therefore, when we drain wet land, it can not 

 be suflScient to dig ditches through a great area and discharge the water into 

 streams that are not adapted to that increased rate of flow. In rational 

 drainage it is necessary to consider the whole basin — the hill land as well 

 as the low land, and the drainage system must be fashioned with due regard 

 for every part. The necessities differ in no essential degree from those of a 

 sewerage system of any city. No one would think of building the upper end 

 of the system without regard to the lower end, nor of dividing the problem 

 up into districts to conform, for example with city ward lines, and construc- 

 ing each without regard to the other. In laying out a city sewerage system 

 we must at the outset design each portion, from outlet to highest point, so 

 that when the whole is eventually completed it will become an harmonious 

 drainage work. The same plan is demanded in swamp drainage. Whether 

 the swamp be one mile or one thousand miles long, it must, if included within 

 a single river system, eventually be reclaimed as a unit. Of course this does 

 not apply to coastal marshes like those of Louisiana, where the logical process 

 is to dike off lands and to pump the surplus water into canals that discharge 

 directly into the ocean. It applies, however, to by far the greater area of 

 our swamps, where the reclamation must be accomplished by gravity drainage 

 into natural streams already established. In such cases those natural streams 

 must be enlarged and adjusted as far down their courses as is necessary, and 

 even at times to their ultimate reaches. 



That is the way Nature drains — that is the way we must do it. The 

 laws governing drainage differ widely from those governing irrigation. In 

 the latter we must decide how much land can be irrigated with a certain 

 amount of water. We can conduct the water on the land we designate and 

 can leave neighboring lands out of consideration if we choose to do so. This 

 can not be done in drainage work. In a swamp the water is already there. 

 We take it out by digging gravity canals and lowering the water table. We 

 can not define offhand the extent of land that is to be benefited by that canal. 

 The extent of the benefit depends on natural soil conditions, and the influence 

 exerted by a drainage canal may be narrow or it may be wide. If a drainage 

 district, for example, recognizing that it must provide a suitable outlet for 

 the surplus water that it discharges from the district, enlarges the natural 

 channel or digs a new one beyond the district boundaries far down to a remote 

 point at which a suitable outlet is provided, that channel will benefit by 



