Introduction to Panama Canal

Panama Canal, a ship canal across the Isthmus of Panama joining the Atlantic and Pacific oceans. It runs generally southeastward from Cristobal on the Caribbean Sea (an arm of the Atlantic) to Balboa on the Pacific Ocean. The canal is operated by the Republic of Panama.

The Panama CanalThe Panama Canal created a shortcut from the Atlantic Ocean to the Pacific.

The canal cuts across the lowest point in the continental divide, and through one of the narrowest points between the oceans. An impressive engineering feat, it was built 190414 at an initial cost of $366,650,000. Although it is only half the length of the Suez Canal, it took the same amount of time to build and cost more than three times as much. Unlike the Suez, which is at sea level for its entire length, the Panama Canal has locks to raise and lower ships. Dams hold back two artificial lakes, Gatun and Madden, that supply water for the locks.

The canal was built by the Isthmian Canal Company under the provisions of the Spooner Act, and it was opened in 1914. It was operated by the Panama Canal Commission, a joint United States-Panamanian body until 1999.


The Panama Canal is 50 miles (80 km) long from deep water in the Caribbean to deep water in the Pacific. The dredged portion of the canal has a minimum depth of about 40 feet (12 m) and a minimum width of 500 feet (152 m). Within the locks these dimensions are reduced, and ships with a draft of more than about 37 feet (11 m) or a beam (width) greater than 106 feet (32.3 m) cannot use the canal. A growing number of the world's largest ships are in this group.

There are six massive pairs of locks, each 1,000 feet (305 m) long and 110 feet (33.5 m) wide. Each may be filled or emptied in about 10 minutes, and each pair of lock gates takes about two minutes to open. Water is not pumped into and out of the locks, but flows from the artificial lakes through culverts. Electric towing locomotives called mules pull ships by cable through the locks. Most ships require six of these mules, three on each side.

Tidal ranges vary greatly from one side of the canal to the other. On the Pacific side the difference between high tide and low tide is about 12 feet (3.7 m), compared to less than 2 feet (61 cm) on the Caribbean side.

A ship crossing from the Caribbean Sea starts in Limon Bay. It proceeds at sea level for 6.5 miles (10.5 km) to Gatun, where it is raised 85 feet (26 m) to Gatun Lake by three locks. Then it travels 23.5 miles (37.8 km) through the lake to Gamboa, where it enters Gaillard (Culebra) Cut. After an 8-mile (13-km) trip through the cut the ship reaches Pedro Miguel locks, and is lowered 31 feet (9.4 m) in one step to Miraflores Lake. The two locks at the end of the lake lower the ship to sea level, and it travels another 8 miles (13 km) to the Pacific Ocean. The total passage time ranges from 8 to 15 hours. There are port facilities at both ends of the canal, at Balboa and Cristobal.

Most of the early traffic through the canal was to and from the United States. Since World War II, however, there has been a large increase in cargo moving to and from Europe and the Far East, especially Japan.


The Spanish in the 16th century were the first to become interested in a canal connecting the Atlantic and Pacific oceans. At various times Spain drew up plans, but nothing came of them. When Spanish influence declined in South America, interest in a canal also declined and was not seriously revived until the 19th century. In this period several countries (particularly the United States, France, and Great Britain) began considering a canal across the Isthmus of Panama.

The California gold rush of 1849 led to the building of a railway across the Isthmus by the United States. In 1876 the French surveyed the area and in 1880 began work on a canal under the direction of Ferdinand de Lesseps, builder of the Suez Canal. After extensive operations, the corporation building the canal went bankrupt. A new French company was organized in 1894, but its chief function was to sell the canal assets.

The Spanish-American War in 1898 caused the United States to recognize the military importance of a canal through Central America. In 1899 President McKinley established the Isthmian Canal Commission to study plans for a canal through Nicaragua. When the French agreed to sell their rights in Panama for $40,000,000, the United States Congress passed the Spooner Act in 1902, authorizing construction of a canal there. Panama was then a part of Columbia, which refused to ratify a canal treaty with the United States. With the encouragement of President Theodore Roosevelt, Panama declared its independence in 1903 and agreed to the construction of a canal through the isthmus.


The treaty signed by Panama (the Hay-Bunau-Varilla Treaty) gave the United States a perpetual lease to the Canal Zone (a strip of land five miles [8 km] on each side of the canal); the right to build, operate, and protect the proposed canal; and the right to intervene in the domestic affairs of Panama to prevent political disorder. In return, the United States agreed to guarantee Panama's independence; provide sanitation for cities near the Canal Zone; and pay an initial sum of $10,000,000 and an annual rental of $250,000 (to begin 10 years after the date of treaty ratification). In 1939, the annual rent to Panama was raised to $430,000, and the right to intervene in Panamanian affairs was abolished. The annual rent was raised again, to $1,930,000, in 1955.

New treaties were agreed upon providing for partial control of the canal by Panama. However, the treaties were never ratified. Later negotiations resulted in two treatiesthe Panama Canal Treaty and the Neutrality Treatyboth ratified in 1978. By the terms of the Panama Canal Treaty, the United States turned over to Panama the territory occupied by the Canal Zone in 1979 and transferred the canal itself to Panama on December 31, 1999. The second treaty, the Neutrality Treaty, provided for the perpetual neutrality of the canal when it is operated by Panama.

Construction and Improvements

The United States took over the canal property in 1904. Almost three years were spent in planning, construction of housing, and stamping out yellow fever and malaria, both transmitted by mosquitoes, which thrived in the wet, hot climate. By eliminating mosquito breeding areas, the army medical corps, under Colonel W. C. Gorgas, all but wiped out these diseases.

Early planning was carried out under John F. Stevens. From 1907 until the opening of the canal in 1914, construction was supervised by Colonel G. W. Goethals, an army engineer. During this period the labor force averaged almost 40,000 men, and massive machines were required to dig through solid rock. A temporary railway was built to transport men and supplies. Part of the canal had to be built through the continental divide, and frequent landslides endangered lives and slowed construction.

Maintenance work on the canal goes on continually. In 1955 Contractor's Hill, which was threatening to slide into the canal, was cut back. In 1962 a bridge over the Pacific entrance was completed, joining the two parts of land separated by the canal since 1914. A number of improvements have been undertaken, such as widening the Gaillard Cut and providing mooring facilities near some, of the locks. By the mid-1960's, increasing ship size and ship traffic made it apparent that the canal's size and capacity were no longer adequate. In 1970, a special commission recommended construction of a new sea-level canal.