Page:Popular Science Monthly Volume 74.djvu/442

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perfectly satisfactory canal in very much less time, and for very much less money, under the plan proposed by the minority. I believe that the canal under that plan will cost little more than half what the canal of the majority will cost, and the time will be a little more than half, and when done it will be a better canal, because it will be three times as big a canal. The volume of water in the sea-level canal is only one third what the volume of water is in the lock canal. Leave out everything in those lakes beyond the width of 1,000 feet, and everything beyond a depth of 45 feet, and you have three times the number of cubic yards of water in the lock canal that you have in the sea-level canal.

Among the earliest and best-informed advocates of the lock canal is General Henry L. Abbot, of the Corps of Engineers, U. S. Army (retired), who was a member of the Comité Technique, and was also a member of the board of consulting engineers. General Abbot has been a close, able and careful student of the hydraulic and other problems involved, and ever since the days of the Comité Technique has contributed much to the discussion thereof. In presenting his views to the board of consulting engineers, which are at too great length to be quoted in full, he says:

The most important consideration, from an engineering point of view, in projecting a transit route, whether a railroad or a canal, is to adjust the details to the topography and natural conditions of the region to be traversed. On the Isthmus, the Chagres River is the dominating feature. . . . The deep excavation in the Culebra section is a formidable undertaking, chiefly because it will be necessary to transport the soil to long distances; but once executed, it will remain without giving occasion for anxiety in the future. The Chagres is capable of becoming a very active enemy at any future time, unless effectively tamed by good engineering methods.

General Abbot thereupon discusses the peculiarities of this river, and its relation to the several canal projects. He readies the conclusion that the problem of the control of the Chagres is solved by the lock canal project in a manner at once vastly better and vastly more simple than by the sea-level project. He expresses his judgment, however, that the primary consideration in choosing between the two projects "should be their relative merits as routes for shipping. The elements of time and cost are secondary, but too important to be neglected." According to General Abbot, double the cost and double the time should be allowed for the completion of a sea-level canal, and when completed, the canal would be distinctly inferior to a canal with locks. In the matter of the sufficiency of the flow of Chagres River to maintain the lake above the Gatun dam, at the desired elevation, General Abbot is emphatically of the opinion that the water supply will be adequate. Based on a most

Cubic Feet
per Second
Evaporation loss, estimated 710
Leakage of gates 250
Infiltration 77
For light, power, etc. 200
Contingencies 200
Total 1,437