Panama Canal, waterway across the Isthmus of Panama, connecting the Atlantic (by way of the Caribbean Sea) and Pacific oceans, built by the United States (1904–14) on territory leased from the republic of Panama. The canal, running S and SE from Limón Bay at Colón on the Atlantic to the Bay of Panama at Balboa on the Pacific, is 40 mi (64 km) long from shore to shore and 51 mi (82 km) long between channel entrances. The Pacific terminus is 27 mi (43 km) east of the Caribbean terminus. The minimum depth is 41 ft (12.5 m).
From Limón Bay a ship is raised by Gatún Locks (a set of three) to an elevation 85 ft (25.9 m) above sea level, traverses Gatún Lake, then crosses the Continental Divide through Gaillard (formerly Culebra) Cut and is lowered by Pedro Miguel Lock to Miraflores Lake and then by the Miraflores Locks (a set of two) to sea level. The average tidal range on the Atlantic side is less than a foot (.3 m); that on the Pacific side is 12.6 ft (3.8 m).
U.S. Interest in a Canal
Building an interoceanic canal was suggested early in Spanish colonial times. The United States, interested since the late 18th cent. in trading voyages to the coast of the Pacific Northwest, became greatly concerned with plans for a canal after settlers had begun to pour into Oregon and California. Active negotiations led in 1846 to a treaty, by which the republic of New Granada (consisting of present-day Panama and Colombia) granted the United States transit rights across the Isthmus of Panama in return for a guarantee of the neutrality and sovereignty of New Granada.
The isthmus gained more importance after the United States acquired (1848) California and the gold rush began, and the trans-Panama RR was built (1848–55) with U.S. capital. At the same time, interest in an alternate route, the Nicaragua Canal, was strong in both Great Britain and the United States. Rivalry between the two countries was ended by the Clayton-Bulwer Treaty (1850), which guaranteed that neither power should have exclusive rights or threaten the neutrality of an interoceanic route. In the 1870s and 80s the United States tried unsuccessfully to induce Great Britain to abrogate or amend the Clayton-Bulwer Treaty.
After the United States acquired territory in the Caribbean and in the Pacific as a result of the Spanish-American War (1899), U.S. control over an isthmian canal seemed imperative. Following protracted negotiations, a U.S.-British agreement (see Hay-Pauncefote Treaties) was made in 1901, giving the United States the right to build, and by implication fortify, an isthmian canal. It was then necessary for Congress to choose between Nicaragua or Panama as the route for the canal.
Meanwhile a concession for building a sea-level canal in Panama (granted 1878) was acquired by a French company under Ferdinand de Lesseps. Work began in 1881, but poor planning, disease among the workers, construction troubles, and inadequate financing drove the company into bankruptcy in 1889. Amid charges of corruption and mismanagement, French courts transferred (1894) the rights and assets to a new company. Although the alternate Nicaragua route was favored by the United States, an American representative of the French company, William Nelson Cromwell, began working vigorously to interest the United States in the Panama route, and Philippe Bunau-Varilla, a leading figure in the new company, devoted himself to the cause. When a U.S. commission recommended a canal through Nicaragua in 1901, Bunau-Varilla persuaded the French directors to reduce the price of the company's rights, gaining the support of Mark Hanna and later of President Theodore Roosevelt. The commission reversed its recommendation, and Congress authorized purchase of the French company's rights and construction of the Panama Canal.
Insurrection against Colombia
The Hay-Herrán Treaty, signed (Jan., 1903) with Colombia, would have given the United States a strip of land across the Isthmus of Panama in return for an initial cash payment of $10 million and an annuity of $250,000, but the Colombian senate refused to ratify it. An insurrection, involving Bunau-Varilla and other proponents of the canal as well as the regional population, was encouraged by the United States. Panama rose in revolt on Nov. 3, 1903, declaring itself independent of Colombia. Invoking the treaty of 1846, the United States sent an American warship to Panama, and its presence prevented Colombian troops from quelling the outbreak. The new republic was formally recognized three days later, and on Nov. 17 the Hay–Bunau-Varilla Treaty was signed, granting to the United States, in return for the same terms offered Colombia, exclusive control of a canal zone in perpetuity, other sites necessary for defense, and sanitary control of Panama City and Colón. Colombia's efforts to secure redress for the loss of Panama later resulted in ratification of a treaty (1921) by which the United States paid Colombia $25 million, and Colombia recognized the independence of Panama.
Construction and Improvements
Construction of a lock canal was decided on in 1906. The first three years were spent in the development of construction facilities, surveys, and disease control. The canal was informally opened Aug. 15, 1914; formal dedication took place on July 12, 1920. The total cost was $336,650,000, and c.240 million cu yd (184 million cu m) of earth were evacuated. Madden Dam, which stores additional water for the locks, was completed in 1935.
In 1939 treaty amendments increased Panama's annuity to $434,000 (retroactive to 1934 to offset dollar devaluation), provided for a transisthmian highway, and (at Panama's insistence) abrogated the U.S. guarantee of the neutrality and sovereignty of Panama. Although in the same year Congress authorized construction of a third set of locks, World War II intervened, and the plans were shelved. In 1955 the annuity was raised to $1,930,000, and the United States undertook to build a high-level bridge (completed 1962) over the Pacific side of the canal. The Gaillard Cut was widened in 1969 to permit two-way traffic. The largest modern merchant and fighting ships, however, cannot pass through the canal.
In the 1960s there was increasing agitation in Panama to achieve greater Panamanian control over the canal, resulting in the negotiation of a new treaty (1967) which failed, however, to gain ratification by the Panamanian government. In 1977 negotiations were successful, and a new treaty was signed. It returned the Panama Canal Zone to Panama while setting up joint U.S.-Panamanian control of the canal until the end of 1999, when Panama gained full control. A separate treaty (1979) guarantees the permanent neutrality of the canal. In 0ct., 2006, Panamanian voters approved expanding the canal by adding a third series of locks paralleling the existing locks; the new locks, whose construction was inaugurated in 2007, will be larger, enabling wider, longer vessels with deeper drafts to transit the Isthmus. The plan will utilize the work begun but abandoned on a third series of locks prior to World War II.
See G. W. Goethals, The Panama Canal: An Engineering Treatise (1916); M. P. DuVal, And the Mountains Will Move (1947, repr. 1968); D. G. Payne, The Impossible Dream (1972); J. P. Speller, The Panama Canal (1972); G. H. Summ and T. Kelly, The Good Neighbors: America, Panama, and the 1977 Canal Treaties (1988); A. C. Richard, The Panama Canal in American National Consciousness, 1870–1990 (1990).