A very serious objection to the lock type is that it cannot be readily enlarged. The locks are to be 1,000 feet long and 110 feet wide. This is ample for the present but indications are that future needs will be far greater. If they do become greater the Panama Canal will be an inefficient servant and will come far short of fulfilling the purpose which prompted its building. The sea-level canal could be enlarged by dredges without stopping traffic through it, but with a lock canal it is different. When the locks as constructed become inadequate the only way to increase their capacity is to shut down the canal for years while new and larger ones are being built.
It is unquestionably true that the ideal canal is a sea-level canal 500 feet to 600 feet wide. This is of the type known as the “Straits of Panama” proposed by Philippi-Bunau-Varilla to the consulting board in 1905. There is a growing feeling that this plan is the one which will ultimately be adopted for the completion of the canal. It contemplates the construction of a lock canal to be finally converted into a sea-level canal. The locks were to be constructed so that as the levels were deepened by dredging they could be eliminated, navigation continuing during the enlargement. The material removed by the dredges was to be deposited in the lake formed by a dam at Gamboa. The plan was carefully considered and finally rejected because of the excessive time and cost involved. It is interesting to note what the author of the plans states in regard to it. He says in part, “It is easy to see from the records that this rejection was purely based on the false assumption that the transformation of rock into dredgable ground would cost $2.35 (per cubic yard), when it has since been officially demonstrated to cost eleven times less in the Suez Canal and eighteen times less in the Manchester Canal.”
The cost at Panama of that transformation would be certainly inferior to the cost at Manchester not only on account of the saving of expense due to the gratuitous mechanical power given by the falls of the Chagres but also and principally on account of the extremely soft character of the greater part of the isthmian rocks. The electricity generated by the falls of the lake will put in action the rock breakers, the floating dredges, and the scows. The water in the small barge locks will raise the scows from the level of the summit to that of the lake and the depths of the lake will absorb the material of the straits. Thus the Chagres, once harnessed, will offer freely by its waters the way for the excavating and transporting instruments, by its falls the energy to animate everything and by its upper valley the dump to receive the spoils.
If unbiased and free-minded engineer officers of the army, having no anterior connection with the plans under discussion, should be sent to investigate the nature of the rock on the Isthmus and then to study in France, England, and Japan the actual improved methods of dredging soft and hard material the cloud would soon be dissipated. The supposed chimera would become a real tangible thing and the United States, the trustees of humanity in the construction of the great international waterway, would give to the world what it wants, what it is possible now and easy to obtain, the “Straits of Panama.” This sounds very plausible; and it is a significant fact that engineers do not ridicule it. Their respect for it is growing. Today rock-dredging is on trial at Panama. If its feasibility can be there demonstrated the plan will undoubtedly be adopted.
No man can find objections to this type when once constructed. The objections to the narrow sea-level canal first considered do not apply to the “Straits of Panama”, so they will stand as the ideal solution.
A canal designed to carry the world’s commerce, to furnish free communication between the Atlantic and Pacific should be as free from artificial devices as it is possible to make it. It is therefore hoped that some day the present lock canal will be enlarged to an ideal, wide, sea-level channel.
V. LOCATION, SIZE, AND PLAN
The location, size and plan of the Panama Canal with several recent changes which have been ordered by the President and adopted by the commission is described in the “Canal Record” as follows: “A channel, 500 feet wide at sea-level will lead from deep water in Limon Bay to Gatun, a distance of 6.76 miles. At Gatun a dam one and one-half miles long and 115 feet high will impound the waters of the Chagres river in a lake, the normal level of which will be 85 feet above mean sea-level, A flight of three twin locks, each 1,000 feet long, 110 feet wide, and allowing for 41⅓ feet of water over the sills, will raise vessels from sea-level to the lake, or lower them from the lake to the sea-level channel. From Gatun navigation will be through the lake in a channel from 1,000 feet to 500 feet wide for a distance of 23.59 miles to Bas Obispo where Culebra cut begins. The channel through the continental divide, from Bas Obispo to Pedro Miguel, a distance of 8.11 miles will be 300 feet wide, and the surface of the water will be at the lake level. At Pedro Miguel vessels will be lowered from the 85-foot level to a small lake at 55 feet above sea-level, in twin locks of one flight. A channel 500 feet wide and 0.97 miles long will lead to Miraflores locks, where the descent to sea-level will be made in twin locks of two flights. The locks at Pedro Miguel and Miraflores will be of the same dimensions as those at Gatun. From Miraflores to deep water in Panama Bay, a distance of 8.31 miles, the channel will be 500 feet wide and 45 feet deep at mean tide. The channel widths given are all bottom widths. The entrance both in Limon Bay and in Panama Bay will be protected by breakwaters.”