Whatever type of canal was to be constructed along this route, there were certain excavations which must necessarily be done. These were, firstly, dredging the sea channels, and secondly, making a cut through the solid rocks of the divide. Thus, although de Lesseps started operations upon inadequate data, yet most of the work done by the first Panama Canal Company is available, either for the tide-level canal proposed by de Lesseps or for the 85-foot-level canal now being made by the United States. Similarly, the New Panama Canal Company, although hampered by many uncertainties, continued to work at the Culebra Cut, as it is called, that is to say, the trench through the rocky hills which separate the alluvial valleys of the Chagres and the Rio Grande.
Thus the works taken over by the United States in 1904 were available for any type of canal, and the decision to adopt the 85-foot-level was not taken until 1906. Even now, or in April, 1908, at the time of my visit, when so much work has been done upon the locks, many of the rank and file of the employees still cherish the hope of a tide-level canal, and there are not wanting well-informed people, both on the Isthmus and in the States, who, while accepting the high-level scheme as inevitable, regard a tide-level canal as essentially a better thing.
Let us resume our description of the Isthmus, in order that we may be in a position to understand the conditions with which the engineers have to deal. The practicability of the Panama route is due to the fact that rivers have already done a great part of the excavation, and if desert conditions had supervened—if there were, as at Suez, practically no rainfall—the construction of a tide-level canal would be simply the excavation of a trench in dry material, which would be filled by the inflowing waters of the sea. A tidal lock being added to regulate the ebb and flow at Panama (for the Atlantic side is tideless), the canal would be complete.
But as things actually are, the rainfall on the Isthmus is very heavy, particularly on the Atlantic side, where it reaches 140 inches[5] per annum, and the rivers have at all times considerable bodies of water, and during the rainy season (commencing in May) are subject to sudden and violent freshets. The Chagres at Gamboa has been known to rise 35-1/2 feet in 24 hours.[6] Suppose then that a tide-level trench were suddenly formed across the Isthmus, as by a convulsion of nature. We should then see the rivers pouring into this fjord in a number of cascades of various height. Of these the greatest would be the Chagres cascade, entering from the east near Gamboa and Obispo. The height of the waterfall would be 46 feet in the driest season and as much as 80 feet in occasional floods.[7]
[5] Abbot, "Problems of the Panama Canal," p. 96.
[6] Loc. cit., p. 146.
[7] Abbot, loc. cit., p. 116.
EXCAVATION NEAR TAVERNILLA.
