The Panama Canal
Sudeeshna MukherjeeAssistant Editor,
Civil Engineering and Construction Review
The American Society of Civil Engineers has ranked the Panama Canal one of the seven wonders of the modern worldBut after completion, a challenge remained: how to tame the flood waters of Chagres River, known to rise 25 ft. in a day during monsoon season? Solution: Civil engineers erected a dam that formed the world’s then-largest man-made lake. Today the Canal operates much as it did in 1914. In each transit, 52 million gallons of fresh water is lost, but it is quickly replaced by Panama’s heavy rainfall. The canal remains a testament to the combined skills of structural, geotechnical, hydraulic and sanitary engineers.
France began work on the canal in 1881 but stopped due to engineering problems and a high worker-mortality rate. The United States took over the project in 1904 and opened the canal on August 15, 1914. One of the largest and most difficult engineering projects ever undertaken, the Panama Canal shortcut greatly reduced the time for ships to travel between the Atlantic and Pacific Oceans, enabling them to avoid the lengthy, hazardous Cape Horn route around the southernmost tip of South America via the Drake Passage or Strait of Magellan.
Colombia, France, and later the United States controlled the territory surrounding the canal during construction. The US continued to control the canal and surrounding Panama Canal Zone until the 1977 Torrijos-Carter Treaties provided for handover to Panama. After a period of joint American-Panamanian control, in 1999, the canal was taken over by the Panamanian government. It is now managed and operated by the government-owned Panama Canal Authority.
Annual traffic has risen from about 1,000 ships in 1914, when the canal opened, to 14,702 vessels in 2008, a total of 333.7 million Panama Canal/Universal Measurement System (PC/UMS) tons. By 2012, more than 815,000 vessels had passed through the canal. It takes 11.38 hours to pass through the Panama Canal. The American Society of Civil Engineers has ranked the Panama Canal one of the seven wonders of the modern world.
FRANCEThe first attempt to construct a canal through what was then Colombia’s province of Panama began on January 1, 1881. The project was inspired by the diplomat Ferdinand de Lesseps, who was able to raise considerable funds in France as a result of the huge profits generated by his successful construction of the Suez Canal. Although the Panama Canal needed to be only 40 % of the Suez Canal, it was much more of an engineering challenge due to the combination of tropical rain forests, debilitating climate, the need for canal locks, and the lack of any ancient route to follow.
Workers had to continually widen the main cut through the mountain at Culebra and reduce the angles of the slopes to minimize landslides into the canal. Steam shovels were used in the construction of the canal, purchased from Bay City Industrial Works, a business owned by William L. Clements in Bay City, Michigan. Bucket chain excavators manufactured by both Alphonse Couvreux and Wehyer & Richemond and Buette were also used.
In France, de Lesseps kept the investment and supply of workers flowing long after it was obvious that the targets were not being met, but eventually the money ran out. The French effort went bankrupt in 1889 after reportedly spending US$287,000,000 and an estimated 22,000 men died from disease and accidents, and the savings of 800,000 investors were lost. Work was suspended on May 15, and in the ensuing scandal, known as the Panama affair, some of those deemed responsible were prosecuted, including Gustave Eiffel.
In 1894, a second French company, the Compagnie Nouvelle du Canal de Panama, was created to take over the project. A minimal workforce of a few thousand people was employed primarily to comply with the terms of the Colombian Panama Canal concession, to run the Panama Railroad, and to maintain the existing excavation and equipment in saleable condition. The company sought a buyer for these assets, with an asking price of US$109,000,000. In the meantime, they continued with enough activity to maintain their franchise. Phillipe Bunau-Varilla, the French manager of the New Panama Canal Company, eventually managed to persuade de Lesseps that a lock-and-lake canal was more realistic than a sea-level canal.
USAThe US formally took control of the canal property on May 4, 1904, inheriting from the French a depleted workforce and a vast jumble of buildings, infrastructure, and equipment, much of it in poor condition. A US government commission, the Isthmian Canal Commission (ICC), was established to oversee construction. It was given control of the Panama Canal Zone, over which the United States exercised sovereignty. The commission reported directly to Secretary of War William Howard Taft and was directed to avoid the inefficiency and corruption that had plagued the French 15 years earlier.
On May 6, 1904, President Theodore Roosevelt appointed John Findley Wallace, formerly chief engineer and finally general manager of the Illinois Central Railroad, as chief engineer of the Panama Canal Project. Overwhelmed by the disease-plagued country and forced to use often dilapidated French infrastructure and equipment, as well as being frustrated by the overly bureaucratic ICC, Wallace resigned abruptly in June 1905. He was succeeded by John Frank Stevens, a self-educated engineer who had built the Great Northern Railroad. Stevens was not a member of the ICC; he increasingly viewed its bureaucracy as a serious hindrance, bypassing the commission and sending requests and demands directly to the Roosevelt administration in Washington, DC.
One of Stevens’ first achievements in Panama was in building and rebuilding the housing, cafeterias, hotels, water systems, repair shops, warehouses, and other infrastructure needed by the thousands of incoming workers. Stevens began the recruitment effort to entice thousands of workers from the United States and other areas to come to the Canal Zone to work and tried to provide accommodation in which the incoming workers could work and live in reasonable safety and comfort. He also re-established and enlarged the railway, which was to prove crucial in transporting millions of tons of soil from the cut through the mountains to the dam across the Chagres River.
In 1905, a US engineering panel was commissioned to review the canal design, which had not been finalized. The panel recommended to President Roosevelt a sea-level canal, as had been attempted by the French. But in 1906 Stevens, who had seen the Chagres in full flood, was summoned to Washington; he declared a sea-level approach to be “an entirely untenable proposition”. He argued in favour of a canal using a lock system to raise and lower ships from a large reservoir 26 m above sea level. This would create both the largest dam (Gatun Dam) and the largest man-made lake (Gatun Lake) in the world at that time. The water to refill the locks would be taken from Gatun Lake by opening and closing enormous gates and valves and letting gravity propel the water from the lake. Gatun Lake would connect to the Pacific through the mountains at the Gaillard (Culebra) Cut. Stevens successfully convinced Roosevelt of the necessity and feasibility of this alternative scheme.
The construction of a canal with locks required the excavation of more than 130,000,000 m3 of material over and above the 23,000,000 m3 excavated by the French. As quickly as possible, the Americans replaced or upgraded the old, unusable French equipment with new construction equipment that was designed for a much larger and faster scale of work. About 102 new large, railroad-mounted steam shovels were purchased from the Marion Power Shovel Company and brought from the United States. These were joined by enormous steam-powered cranes, giant hydraulic rock crushers, concrete mixers, dredges, and pneumatic power drills, nearly all of which were manufactured by new, extensive machine-building technology developed and built in the United States. The railroad also had to be comprehensively upgraded with heavy-duty, double-tracked rails over most of the line to accommodate new rolling stock. In many places, the new Gatun Lake flooded over the original rail line, and a new line had to be constructed above Gatun Lake’s waterline.
LAYOUTWhile globally the Atlantic Ocean is east of the Isthmus and the Pacific is west, the general direction of the canal passage from the Atlantic to the Pacific is from northwest to southeast, because of the shape of the Isthmus at the point the canal occupies. The Bridge of the America at the Pacific side is about a third of a degree east of the Colón-end on the Atlantic side. Still, in formal nautical communications, the simplified directions “southbound” and “northbound” are used.
The canal consists of artificial lakes, several improved and artificial channels, and three sets of locks. An additional artificial lake, Alajuela Lake (known during the American era as Madden Lake), acts as a reservoir for the canal. The layout of the canal as seen by a ship passing from the Atlantic to the Pacific is:
– From the formal marking line of the Atlantic Entrance, one enters Limón Bay (Bahía Limón), a large natural harbour. The entrance runs 5½ mi (8.4 km). It provides a deep-water port (Cristóbal), with facilities like multimodal cargo exchange (to and from train) and the Colón Free Trade Zone (a free port).
– A 3.2 km channel forms the approach to the locks from the Atlantic side.
– The Gatun Locks, a three-stage flight of locks 1.9 km long, lifts ships to the Gatun Lake level, some 27 m above sea level.
– Gatun Lake, an artificial lake formed by the building of the Gatun Dam, carries vessels 24 km across the isthmus. It is the summit canal stretch, fed by the Gatun River and emptied by basic lock operations.
– From the lake, the Chagres River, a natural waterway enhanced by the damming of Gatun Lake, runs about 8.5 km. Here the upper Chagres River feeds the high-level canal stretch.
– The Culebra Cut slices 12.4 km through the mountain ridge, crosses the continental divide and passes under the Centennial Bridge.
– The single-stage Pedro Miguel Lock, which is 1.4 km long, is the first part of the descent with a lift of 9.4 m.
– The artificial Miraflores Lake 1.7 km long, and 16 m above sea level.
– The two-stage Miraflores Locks is 1.7 km long, with a total descent of 16 m at mid-tide.
– From the Miraflores Locks one reaches Balboa harbour, again with multimodal exchange provision (here the railway meets the shipping route again). Nearby is Panama City.
– From this harbour an entrance/exit channel leads to the Pacific Ocean (Gulf of Panama), 13.2 km from the Miraflores Locks, passing under the Bridge of the Americas.
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