Panama Canal

The canal joining the Atlantic and Pacific oceans across the Isthmus of Panama. Running from Cristóbal on Limón Bay, an arm of the Caribbean Sea, to Balboa, on the Gulf of Panama, the canal is slightly more than 40 mi long, not including the dredged approach channels at either end. The minimum depth is 41 ft, and the minimum width is 300 ft. The construction of the Panama Canal ranks as one of the greatest engineering works of all time.
Location and Structure
The approach to the canal from the Atlantic is along 4.5 mi of dredged channel. The canal then proceeds for 6.9 mi, veering slightly westward before reaching the Gatun Locks. Ships are lifted 85 ft by these three locks, to the level of Gatun Lake. The lake was formed as a result of the damming of the Chagres River by the Gatun Dam, which adjoins the locks. The Gatun Locks open directly into one another and are double, as are the other locks, so that one ship can be raised while another is being lowered. All the lock chambers on the Panama Canal have a length of 1000 ft and a width of 110 ft. From the Gatun Locks the canal passes through Gatun Lake in a southern and southeastern direction to the mouth of Gaillard Cut, an excavated channel 8.1 mi long. At the end of the Gaillard Cut is the Pedro Miguel Lock, which has a drop of 31 ft. The lock borders Miraflores Lake, which is 55 ft above the level of the Pacific. The canal passes 1.3 mi through Miraflores Lake and reaches the two Miraflores Locks. These locks lower ships to Pacific tidewater level.0 From the Miraflores Locks the canal runs 21/2mi to Balboa on the Gulf of Panama, from which a dredged channel extends approximately 5 mi out into the bay. In addition to the canal itself, auxiliary facilities include the Madden Dam on the Chagres River, which provides a reservoir to maintain the level of Gatun Lake during the dry season breakwaters to protect the channels at either end of the canal; hydroelectric plants at the Gatun and Madden dams; and the Panama Railroad that extends 47.6 mi from Colón at the Atlantic end of the canal to Panama City on the Pacific. In 1993 about 12,080 vessels, carrying more than 160 million metric tons of cargo, passed through the canal. Time to get through the canal is seven to eight hours.
History

Interest in a short route from the Atlantic to the Pacific began with the explorers of Central America early in the 16th century. Hernan Cortes, the Spanish conqueror of Mexico, suggested a canal across the Isthmus of Tehuantepec; other explorers favored routes through Nicaragua and Darién. The first project for a canal through the Isthmus of Panama was initiated by Holy Roman Emperor Charles V, who in 1523 ordered a survey of the isthmus. A working plan for a canal was drawn up as early as 1529, but was not submitted to the king. In 1534 a local Spanish official suggested a canal route close to that of the present canal. Later, several other canal plans were suggested, but no action was taken.
Renewed Interest
The Spanish government subsequently abandoned its interest in the canal, but in the early 19th century the books of the German scientist Alexander von Humboldt revived interest in the project, and in 1819 the Spanish government formally authorized the construction of a canal and the creation of a company to build it. Nothing came of this effort, however, and the revolt of the Spanish colonies soon took the control of possible canal sites out of Spanish hands.The republics of Central America subsequently tried to interest groups in the United States and Europe in building a canal, and it became a subject of perennial debate in the Congress of the United States. The discovery of gold in California in 1848 and the rush of would-be miners stimulated U.S. interest in digging the canal Various surveys made between 1850 and 1875 indicated that only two routes were practical, the one across Panama and that across Nicaragua. In 1876 an international company was organized; two years later it obtained a concession from the Colombian government-Panama was then part of Colombia-to dig a canal across the isthmus.
U.S. Involvement
The international company failed, and in 1880 a French company was organized by Ferdinand Marie de Lesseps, the builder of the Suez Canal. His company went bankrupt in 1889. U.S. interest in an Atlantic-Pacific canal, however, continued. In 1899 the U.S. Congress created an Isthmian Canal Commission to examine the possibilities of a Central American canal and to recommend a route. The commission first decided on the Nicaraguan route, but reversed its decision in 1902 when the reorganized Lesseps company offered its assets to the United States at a price of $40 million. The U.S. government negotiated with the Colombian government to obtain a strip of land 6 mi wide across the isthmus, but the Colombian Senate refused to except this concession. In 1903, however, Panama revolted from Colombia. That same year the United States and the new state of Panama signed the Hay-Bunau-Varilla Treaty by which the United States guaranteed the independence of Panama and secured a perpetual lease on a 10-mi strip for the canal. Panama was to be compensated by an initial payment of $10 million and an annuity of $250,000, beginning in 1913. The figure was later revised upward in 1936 to $430,000, and in 1955 to $2 million per year.
Construction
The Isthmian Canal Commission decided to build a canal with locks rather than a sea-level channel, and this plan was approved by the U.S. Congress the following year. President Theodore Roosevelt put the construction work under the direction of the U.S. Army Corps of Engineers; Colonel George W. Goethals was named to head the project. It was estimated that the canal would be completed in ten years; however, it was in operation by the summer of 1914. The construction involved not only excavating an estimated 143 million cubic meters of earth, but also sanitizing the entire canal area, which was infested with the mosquitoes that spread yellow fever and malaria. The sanitation work was undertaken by Colonel William C. Gorgas of the U.S. Army Medical Corps, who virtually eliminated the diseases. An unexpected difficulty in the actual construction was the prevalence of slides of earth from the banks of the canal, particularly in the Gaillard Cut. Reexcavation after such slides added about 25 percent to the estimated amount of earth moved. The final cost of the canal was $336 million. One of the most important later pieces of construction work is the $20 million Thatcher Ferry Bridge, which spans the Pacific entrance to the canal and provides a vital link in the Pan-American Highway. This high-level span, 5425 ft long, was dedicated in 1962. The widening of the Gaillard Cut from 300 ft to a width of 600 ft was completed in 1970. It permitted, for the first time, two-way passage through the entire cut.
Agreement
In 1977 the United States and Panama agreed on two new treaties to replace their 1903 agreement. These treaties provided for Panama's sovereignty over the Canal Zone shortly after their ratification and its control of the canal itself at the beginning of 2000, but left the United States the right to defend the canal's neutrality even thereafter. The treaties took effect in 1979.