Page:Popular Science Monthly Volume 71.djvu/142

136 drawn up for this committee a clause which requires them to report upon the possibility of using locks and dams similar to those in use on the Ohio; in other words, to ascertain whether the canalization project is feasible for the Mississippi River. It is this project of canalization which has aroused opposition. Some of the proposers of this plan of improvement, and they were probably the instigators of this section of the bill, have advocated canalization as the only means of obtaining the requisite depth of channel. It is but just to assume that the business men of the valley, and especially the St. Louis contingent, have a definite and well-considered plan for gaining a deeper waterway. At the same time it is unfortunate that their desires should have been introduced to the general public as an undertaking of stupendous magnitude and a work which the public would be forced to promote. An extravagant speech in congress which pictured the bounds of a canalization plant as "two granite walls, 200 feet high and 2,000 miles long" in comparison with which the Chinese wall "7 feet high and only about 450 miles long" is diminutive, was probably no more excessive than the terms by which the speaker may have been informed of the project.

The canalization of a river is not a new method of benefiting the navigable quality of a river. Many streams in Europe, as the Elbe, Seine and the Main, and some streams in this country, portions of the Ohio, for example, have been regulated successfully by this method. The canalization of a stream turns the river into a series of steps; passage from one step to the next higher or lower is made through a lock, and the height of water is sustained by a dam across the main channel of the river. The stream-flow is thus blocked and navigation is as easy up-stream as down. The best arrangement of dam and lock is possible when an island divides the stream into a main channel and a chute. If the dam or weir is located in the main channel and the lock in the secondary channel, high-water stages are not as likely to impair the locks. The weir, however, must be made movable so as not to oppose the flood force. This, in brief, is the process of canalization. While the projectors of this plan for the Mississippi River have not definitely stated what type of canalization plant they advocate, there are certain features which above others must enter into the consideration of every project of a serious nature. A few of the most salient of the characteristics I desire to mention, and, without taking issue with the promoters of canalization, to point out, here and there, the probable effects of these on canalization works.

The discharge of the river is enormous. The potent factors in river discharges are the precipitation of rain over its basin and the porosity of the soil of the basin. The Mississippi River system drains about one third of the United States. The annual discharge of the river is greater than the combined annual discharges of the Po, Danube and the Rhone. This body of water fluctuates in its flow from a flood stage in the spring