Why the Pacific Locks of the Panama Canal were Constructed as Two Separate Structures Rather than as a Single Complex Similar to the Atlantic Locks

In the Panama Canal, vessels transit between the Atlantic and the Pacific oceans, through artificial lakes Gatun and Miraflores, in a system that works by gravity. There are navigation locks at both ends of the canal. On the Atlantic side, vessels are lifted 26 meters to Gatun Lake in three steps in the Gatun Locks. On the Pacific side, vessels first ascend two steps in the Miraflores Locks, then navigate two kilometers through Miraflores Lake and finally ascend a step at Pedro Miguel Locks to Gatun Lake. Given this asymmetry between the two ends of the Canal, the question arises: Why didn’t the Panama Canal builders merge together the three steps in the Pacific side in a single structure, just as in the Atlantic side? After analyzing the project historical documentation, the experience gained during almost a century of operations and the geological investigations carried out in the Panama Canal, the author concluded that there were reasons that affected the decision to separate the locks in the Pacific side, which were not officially documented by the Panama Canal chief engineer, Colonel George Washington Goethals. Unexpected geological findings below the lock structures in July 1907, caused hurried investigations to develop major changes to the original project, just a few months before the visit to Panama of the President of the United States, Theodore Roosevelt. Based on the information available, Goethals decided to separate the Pacific Locks, shortly before he travelled to Washington in December 1907, to update the United States Congress on the project changes. However, while Goethals was away, engineers found in Panama that a single three-lift lock structure at Miraflores was a better solution. The debate lasted until June 1909, when Goethals finally explained that due to the progress in the construction of the locks, such change would seriously delay the opening of the Canal. Moreover, there was the possibility that opportunistic reporters could alarm the public with sensational stories and that the occasion could be used by those who wanted to return to a sea-level canal project, or to abandon the construction of the canal in Panama and enable the resurrection of a canal in Nicaragua.