Page:Popular Science Monthly Volume 74.djvu/437

From Wikisource
Jump to navigation Jump to search
This page has been proofread, but needs to be validated.
433
THE TYPE OF THE PANAMA CANAL

Mr. Wallace formulates certain propositions which he considers fundamental and others which are essential in arriving at the most desirable plan of canal. He says that the most desirable canal is the sea-level canal of such dimensions as would afford unrestricted passage for the largest vessels afloat, with such margin for increase in size and draft as can reasonably be anticipated, making allowance for unexpected developments. No plan should be adopted that would prevent the ultimate construction of a sea-level canal at least approximately approaching to the final idea of the Straits of Panama. Time and cost should be considered to the extreme limit before determining upon a plan which would interfere with this ultimately desirable accomplishment. It is highly desirable that no dams should be constructed the foundations of which can not be carried to bed rock, or at least impervious curtain connection be made therewith. No high dam should be constructed, the destruction of which, by accident or design, would close navigation through the canal until its restoration. If it is absolutely essential to the project that such dams be constructed, they should retain the lowest possible head of water and be of such a nature as not to require the use of experimental, new or untried methods of construction. If terminal lakes are to be formed, the dams creating them should be as low as possible imposing the minimum weight upon the subsoil. The construction of even a low barrage at the Rio Grande Delta would undoubtedly encounter innumerable difficulties in crossing localities where the sub-formation would be such as to give way under the imposition of the weight of material placed thereon. The same obstacle would probably be met to a greater or less extent in the construction of a dam, particularly a high one, in the vicinity of Gatun. The entire valley to at least a depth of 200 feet is alluvial. It is therefore, highly improbable that in the heterogeneous mass of material with which the ancient gorge is filled, particularly near the surface, that unforeseen difficulties in securing proper foundation would not be encountered.

Mr. Wallace repeats to the board of engineers the recommendation which he had already made of the canal commission, that no temporary or tentative plan should be adopted that will interfere with the final adoption of the sea-level plan.

Mr. Quellennec, of the board of consulting engineers, at a board meeting on November 18, 1905, explained his stand in favor of a sea-level canal, stating that it was undeniable that a sea-level canal is preferable to a high-level multi-lock canal both with a view to safety and to facility of operation. He referred to his experience on the Suez Canal which has convinced him of the advantages offered by a sea-level canal. In spite of greater time and cost, he believes the sea-level canal at Panama should be constructed, but in making this statement