Canadian Society of Civil Engineers. SESSION, 1889. TRANSACTIONS. Thursday, 3rd January. SAMUEL KEEFER, President, in the Chair. The following candidates having been balloted for were declared duly elected as HONORARY MEMBERS. THE RIGHT HON, LORD STANLEY OF PRESTON, G. C. B., P. C., &c. SIR JOHN WILLIAM DAWSON, C. M. G., M. A., L. L. D., F. R. S.. The following has been transferred from the class of Students to that of Associate Members, FRANCIS W. W. DOANE. THE PANAMA CANAL. By E. DENIEL, M.CAN. SOC.C.E. Twenty years hardly had elapsed since the discovery of the new continent, when Saavedra, a Spaniard, proposed to cut a canal through the Isthmus of Darien (1520), and only eight years later, the Portuguese Antonio Galvao indicated four different routes through the Isthmuses of Mexico, Nicaragua, Panama and Darien. The idea of uniting the Atlantic and Pacific Oceans has never been abandoned since, and, successively or simultaneously, Spaniards, Portuguese, Englishmen, Frenchmen, Americans, Belgians, etc., have explored the American Isthmus, with the hope of finding an adequate solution to that mighty problem. Navigators, soldiers, engineers, financiers, scholars, even princes and kings, have been attracted by the desire to attach their names to that great work, and have devoted to it, time, labor and money. Wealth and science, walking hand in hand, cannot fail to attain their goal, and after two hundred and sixty years of hard toil, the execution of that gigantic enterprise has at last been undertaken. It is not the object of this communication to give a history or even a sketch of all the works and discoveries made by these daring pioneers; but, without in any way lessening the share of fame and glory achieved by the present promoters and directors, it must not be forgotten that they have been reaping the benefit of the explorations made by their predecessors, and that if to-day the period of execution has been opened, it is due as much to the pressing need of means of rapid communication as to the energy and ability displayed by Messrs. Wise, de Lesseps, and others. The meeting of the "Congrès International," in 1879, the formation of the "Société Internationale du Canal Interocéanique de Panama," in 1880, and the opening of the works in 1881, are events still fresh in every memory; we will therefore enter at once into a description of the proposed Panama canal, and of the works executed up to January 1st, 1888. 1000 The length of the canal is, from deep water to deep water, 75 50 kilometers, or 473 miles. Starting from Colon, on the Atlantic Coast, the canal follows the shore of Limon Bay for some three miles, and about three miles further strikes the valley of the Rio Chagres, crossing for the first time the bed of that river; then it follows the general direction of that valley up to Gamboa, a distance of 22 miles. At point, the Rio Chagres changes its course nearly at right angles, but the canal continues from here in a nearly straight line towards the shores of the Pacific Ocean, following first the valley of the Rio Obispo one of the tributaries of the Rio Chagres, for about five miles. There it has reached the back-bone of the Isthmus; no more valleys, no more "rios," but only a depression in the chain of mountains that have formed a barrier between the two Oceans. Through this, hardly two miles, passes the canal. On the western slope, the valley of the Rio Grande brings it to the sea-shore eight miles distant, and a cut in Panama Bay three miles and a half in length, is all that is now needed to reach deep water. The Rio Chagres, Rio Obispo, and Rio Grande are very tortuous, winding rivers, running with a swift current, carrying along trees and debris of all sorts, constantly forming shoals of these materials, and shifting them here and there. Properly speaking they are torrents, and their discharge varies within very considerable limits, but within very short periods of time. The Rio Chagres, for instance, has, at Gamboa, a discharge of 2,500 gallons per second during the dry season, but this increases to 43,000 gallons per second during the wet season, and is known even to have been 130,000 during freshets. These freshets are very rapid; it is a common occurrence for this river to rise thirty feet in a few hours and there are on record, though fortunately not frequent, instances of sudden rises of fifty feet. The plan at first proposed by Mr. Wise was to create in rear of Gamboa an immense reservoir, of a sufficient capacity to hold the water coming from the upper part of the river during these freshets, with outlets allowing a discharge of 43,000 gallons per second. The creation of that basin would have necessitated the erection of several dams, the main one being nearly one mile in length, one hundred and fifty feet in height, seven hundred and ninety feet in width at top, and three thousand one hundred and fifty feet at the base. As the bed of alluvial deposit is at that point ninety feet thick, this dam was to have been built of clay and rock, without any more masonry than would have been necessary for the sluice ways. The maximum height of the water in rear of this dam would have been 125 feet. Twenty-five millions of cubic yards of materials had been calculated as being required for this work. That solution, however, has since been discarded by the engineers as too bold, while at the same time it did not afford a sufficiently satisfactory settlement to the difficulty. It was finally decided not to admit any water course into the canal, but to dig beds for the rivers on both sides. However a very large dam will have to be built at Gamboa, but without |
