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58-598: Construction of the dam was a great engineering achievement, eclipsed only by the parallel excavation of the Culebra Cut ; at the time of completion, the dam was the largest earth dam in the world, and Gatun Lake was the largest artificial lake in the world. The dam is situated in the valley of the Chagres River, about 10 kilometres (6.2 mi) from its mouth in the Caribbean Sea . The hills bordering

116-636: A brain tumor in Baltimore , Maryland, and hence he did not live to see the opening of the canal in 1914. The Culebra Cut , as it was originally known, was renamed to the Gaillard Cut on April 27, 1915, in his honor. After the handing over of the canal to Panama in 2000, the old name Culebra Cut was reinstated. 9°4′38″N 79°40′31″W  /  9.07722°N 79.67528°W  / 9.07722; -79.67528 Isthmus of Panama The Isthmus of Panama ( Spanish : Istmo de Panamá )

174-677: A colony in the Darién Gap in the late 1690s. The plan was for the colony, located on the Gulf of Darién , to establish and manage an overland route to connect the Pacific and Atlantic Oceans. The backers knew that the first sighting of the Pacific Ocean by Vasco Núñez de Balboa was after crossing the isthmus through Darién . The expedition also claimed sovereignty over "Crab Isle" (modern day Vieques, Puerto Rico ) in 1698, yet sovereignty

232-461: A high level. After this, the sediment in the upper levels of the cut were removed, resulting in less weight over the weak strata. Landslides continued to be a problem after the canal's opening, causing intermittent closures. Steam shovels broke through the Culebra Cut on May 20, 1913. The Americans had lowered the summit of the cut from 59 to 12 metres (194 to 39 ft) above sea level, at

290-509: A place of global significance. Its formation as a geological feature had several biological and climatic effects that resonated on a planetary scale. The separation of the oceans increased marine biodiversity on both sides, and the connection between the American continents allowed for the interchange of terrestrial life. The formation of the isthmus fundamentally changed the system of inter-ocean circulation of warm and cold currents, which caused

348-409: A pond created between the inner and outer walls of the dam. The pumped mixture was allowed to sit until the clay settled out, with the excess water being drawn off and pumped back downstream. This dried and hardened material created a solid core of "natural" cement at the core of the dam. After the dam was built to its desired height, the entire up-stream side was armored to prevent wave action damaging

406-579: A reservoir and hydroelectric power for Panama City , opening in 1935. 9°16′N 79°56′W  /  9.267°N 79.933°W  / 9.267; -79.933 Culebra Cut The Culebra Cut , formerly called Gaillard Cut , is an artificial valley that cuts through the Continental Divide in Panama . The cut forms part of the Panama Canal , linking Gatun Lake , and thereby

464-448: A single blast. The excavation of the cut was one of the greatest areas of uncertainty in the creation of the canal, due to the unpredicted large landslides . The International Board of Consulting Engineers had mistakenly decided that the rock would be stable at a height of 73.5 metres (241 ft) with a slope of 1 in 1.5; in practice, the rock began to collapse from that slope at a height of only 19.5 metres (64 ft). The misjudgment

522-512: A wall 1 + 1 ⁄ 2 metres high and 29 cm thick (or four foot eight inches high and a foot thick) around the Earth at the equator. After the opening of the Panama Canal, it was found that the water level impounded by the dam did not stay constant enough during the dry season for the operation of the canal. The Madden Dam was constructed much higher up the Chagres River to provide

580-417: Is about as much as the Chagres River brings down in an average year. The dam incorporates a hydro-electric generating station, which is situated on the east side of the spillway discharge channel. This uses water from the lake to drive a number of turbine - generators ; as first commissioned, three generators were installed, producing a total of 6 megawatts (8,000 hp) of electricity. The power generated

638-538: Is the narrow strip of land that lies between the Caribbean Sea and the Pacific Ocean , linking North and South America . It contains the country of Panama and the Panama Canal . Like many isthmuses , it is a location of great geopolitical and strategic importance. The isthmus is thought to have been finally formed around 3 million years ago ( Ma ), separating the Atlantic and Pacific Oceans and causing

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696-627: Is used for the operation of the lock and spillway machinery, and for the lighting of the locks and the canal villages. The canal effort was begun by a French company ( La Compagnie Universelle du Canal Interoceanique ) in 1880 to 1889. With poor exploration of the options and with poor information of the costs, the French company planned to construct a sea-level canal linking the two coasts. They initially thought they could do this for about $ 120 million. After spending about one billion Francs (about $ 300,000,000), losing about 22,000 workers and going bankrupt,

754-599: The Cueva , experienced genocidal effects from European colonization of the Isthmus. A regional slave trade in Indigenous peoples was carried out by the colonizing forces in the early 16th century across Central America from Panama to Nicaragua. Deadly working conditions, wars of conquest, and the destruction of Indigenous communities and infrastructure resulted in the complete destruction and dispersal of Indigenous peoples from

812-465: The Isthmus of Panama including through the treacherous V-shaped Culebra Cut (Gaillard Cut). This saved excavating literally millions of cubic yards of material that would have been necessary for a sea-level canal. The lake height is regulated by spillways that control the water flow out of the dam to obtain an almost constant height in wet or dry seasons. The lake also acts as a massive reservoir to work

870-401: The American effort started work on a cut that was wider but not as deep, as part of a new plan for an elevated lock -based canal, with a bottom width of 91 metres (299 ft); this would require creation of a valley up to 540 metres (0.34 mi) wide at the top. A vast amount of new earthmoving equipment was imported, and a comprehensive system of railways was constructed for the removal of

928-604: The Atlantic Ocean, to the Gulf of Panama and hence the Pacific Ocean. It is 7.8 miles (12.6 km) from the Pedro Miguel lock on the Pacific side to the Chagres River arm of Lake Gatun, with a water level 85 feet (26 m) above sea level . Construction of the cut was one of the great engineering feats of its time; the immense effort required to complete it was justified by the great significance of

986-504: The Atlantic and Pacific by between 12 and 9.2 Ma. However exchange of surface water so as to maintain western Atlantic salinity at eastern Pacific values continued until about 4.6 Ma with current Caribbean values being reached by about 4.2 Ma although there seems to have been a last definite temporary breach as recently as 2.45 Ma. The ocean sediments between the volcanoes on the isthmus seem to have been laid down as recently as 3.1 Ma and

1044-585: The Caribbean coast. In 1519 the town of Panamá was founded near a small indigenous settlement on the Pacific coast. In 1671 the Welsh privateer Henry Morgan crossed the Isthmus of Panamá from the Caribbean side and destroyed the city . The town was relocated some kilometers to the west at a small peninsula. The ruins of the old town, Panamá Viejo , are preserved and were declared a UNESCO World Heritage Site in 1997. The local Indigenous population, known as

1102-404: The Chagres River opened very wide around the area that is now Gatun Lake. Over a narrow gap the hills close to a relatively narrow gap with a natural rock-based channel in the centre. This allows a moderately sized dam to enclose a huge body of water, which both provides passage for ships across much of the isthmus, and provides a reservoir of water with which to operate the locks. The central hill

1160-540: The Culebra Cut) and the Gatun Locks excavation. Between these waste rock walls an impervious core was created by using a hydraulic fill technique which pumped millions of cubic yards of clay material and water into the area between the rock walls. This fill was made by digging up the soft clay present in the valley below, where dredges excavated the clay and water and loaded it into pumps that delivered it up into

1218-529: The French effort essentially ceased. A sea level canal would not have required the dam to be built but would have still required extensive provisions made to accommodate the ever-changing Chagres River flow. The United States took over the 10 miles (16 km) wide Canal Zone and resumed building the canal on 4 May 1904. Almost two years were spent in infra-structure preparation, mosquito abatement (the newly discovered vector spreading Yellow fever and Malaria ), Panama Railroad improvements, and planning before

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1276-608: The Isthmus of Panama also played a major role in biodiversity on the planet. The bridge made it easier for animals and plants to migrate between the two continents. This event is known in paleontology as the Great American Interchange . For instance, in North America, the opossum , armadillo , and porcupine all trace back to ancestors that came across the land bridge from South America. Likewise, bears, cats, dogs, horses, llamas, and raccoons all made

1334-681: The Pacific side, they boarded Pacific Mail Steamship Company vessels headed for San Francisco . Ferdinand de Lesseps , the developer of the Suez Canal , started a Panama Canal Company in 1880 that went bankrupt in 1889 in the Panama scandals . In 1902–1904, the United States forced Colombia to grant independence to the Department of the Isthmus , bought the remaining assets of the Panama Canal Company, and finished

1392-482: The Yucatan. By 1501, when Europeans first arrived, the isthmus was inhabited widely by Chibchan- and Chocoan -speaking peoples. Vasco Núñez de Balboa , a Spanish conquistador, was the first European to reach the Pacific Ocean on 25 September, 1513, then called the "South Sea" as it was on the south side of the Isthmus. Balboa had heard of a second ocean on the other side of the Isthmus from natives while sailing along

1450-672: The canal in 1914. A significant body of water (referred to as the Central American Seaway ) once separated the continents of North and South America, allowing the waters of the Pacific and Atlantic Oceans to mix freely. Beneath the surface, two plates of the Earth's crust were slowly colliding, forcing the Cocos Plate to slide under the Caribbean Plate . The pressure and heat caused by this collision led to

1508-429: The canal to shipping , and in particular the strategic interests of the United States of America. Culebra is the name for the mountain ridge it cuts through, and was also originally applied to the cut itself. From 1915 to 2000 the cut was named Gaillard Cut after US Major David du Bose Gaillard , who had led the excavation. After the canal handover to Panama in 2000, the name was changed back to Culebra . In Spanish

1566-423: The capacity of the spillway is 4,100 cubic metres (140,000 cu ft) per second, more than the maximum flow of the Chagres River. In addition to this, the culverts in the locks can dispose of 1,400 cubic metres (49,000 cu ft) per second. Gatun Lake has an area of 425 square kilometres (164 sq mi) at its normal level; it stores 5.2 cubic kilometres (4,200,000 acre⋅ft) of water, which

1624-452: The collapse of the French effort, which was bought out by the United States in 1904. The French had excavated some 14,256,000 cubic metres (18,646,000 cu yd) of material from the cut, and had lowered the summit from 64 meters (210 feet) above sea level to 59 meters (194 feet), over a relatively narrow width. The United States took over on May 4, 1904. Under the leadership of John F. Stevens , and later George Washington Goethals ,

1682-606: The creation of the Gulf Stream , as first suggested in 1910 by Henry Fairfield Osborn . Osborn based the proposal on the fossil record of mammals in Central America, a conclusion that would provide a foundation for Alfred Wegener when he proposed the theory of continental drift in 1912. Some recent studies suggest an earlier formation of the isthmus than the recognized age of 3 Ma, potentially stretching as far back as 19 Ma. The Isthmus of Panama has always been

1740-424: The creation of this land mass and the subsequent warm, wet weather over northern Europe resulted in the formation of a large Arctic ice cap and contributed to the current ice age . That warm currents can lead to glacier formation may seem counterintuitive, but heated air flowing over the warm Gulf Stream can hold more moisture. The result is increased precipitation that contributes to snow pack. The formation of

1798-537: The cut is known as the Corte Culebra and is also called the Snake Cut . The excavation of the cut was begun by a French venture, led by Ferdinand de Lesseps , which was attempting to build a sea-level canal between the oceans, with a bottom width of 22 meters (72 feet). Digging at Culebra began on January 22, 1881. A combination of disease, underestimation of the problem, and financial difficulties led to

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1856-473: The dam by placing large boulders on the face, particularly where there is strong wave action. The dam contains some 17,000,000 cubic metres (600,000,000 cu ft) of material and is about 2,700 feet (820 m) wide at its base, about 105 feet (32 m) high and 7,500 feet (2,300 m) long. The dam weighs some 27,000,000 long tons (30,000,000 short tons). It covers 1.17 square kilometres (290 acres) of ground, and contains enough earth and rock to build

1914-425: The date of first closure, while others suggest that final closure might be more recent based on genetic drift data of black mangroves along the Atlantic and Pacific coasts. The process of formation of the isthmus and its implications is geologically and ecologically more nuanced. There is isotopic and carbonate deposition rate evidence that deep water connections below 1,800 m (5,900 ft) were broken between

1972-454: The dirt trains. They also moved and extended the railroad tracks as the work moved forward. Twice a day work stopped for blasting, and then the steam shovels were moved in to take the loose spoil (dirt and rock) away. More than 600 holes filled with dynamite were fired daily. In all, 27,000 metric tons (60 million pounds) of dynamite were used. In some locations, about 24 metric tons (52,000 lb) of dynamite were planted and detonated for

2030-592: The earliest sites of maize agriculture in the region. The Monagrillo site evolved into a variety of thriving cultural traditions, identified by archeologists as the Gran Coclé culture area. Indigenous peoples in Panama have been connected to the wider regional networks of exchange and diffusion for as long as they have inhabited the isthmus, evident in the presence of Coclé gold work being found as far away as Chichin Itza in

2088-446: The exchange of organism gene pools between the two oceans appears to have continued until about 3 Ma as well. The largest exchange of animals over the land bridge only happened after this time, although some species had made the crossing earlier, perhaps by rafting or brief periods of connection separated by periods of a high water flow between an arc of volcanic islands not conducive to swimming or rafting. Evidence also suggests that

2146-416: The formation of underwater volcanoes , some of which grew large enough to form islands . Meanwhile, movement of the two tectonic plates was also pushing up the sea floor, eventually forcing some areas above sea level. Over time, massive amounts of sediment from North and South America filled the gaps between the newly forming islands. Over millions of years, the sediment deposits added to the islands until

2204-585: The gap was completely filled. However, an article in Science magazine stated that zircon crystals in middle Miocene bedrock from northern Colombia indicated that by 10 Ma, it is likely that instead of islands, a full isthmus between the North and South American continents had already formed where the Central American Seaway had been previously. A genomic study of army ants also suggests that

2262-467: The immense amounts of earthen and rocky spoil . Major David du Bose Gaillard , of the U.S. Army Corps of Engineers , joined the project at the same time as Goethals, and he was put in charge of the central district of the canal, which was responsible for all of the work between Gatun Lake and the Pedro Miguel locks —most notably, the Culebra Cut. Gaillard brought dedication and quiet, clear-sighted leadership to his difficult, complex task. The scale of

2320-712: The isthmus by the Spanish Silver Train to Porto Bello , where Spanish treasure fleets shipped them to Seville and Cádiz from 1707. Lionel Wafer spent four years between 1680 and 1684 among the Kuna or Guna Indians . Scotland tried to establish a settlement in 1698 through the Darien scheme which was ultimately unsuccessful. The scheme was backed largely by investors of the Kingdom of Scotland in order to gain wealth and influence by establishing New Caledonia,

2378-422: The isthmus emerged millions of years earlier than had long been thought. The Isthmus of Panama is not the only part of central America that has been low lying in the last tens of million years. This means the date of first closure and final closure of the Central American Seaway before it was artificially reopened to a degree by the Panama Canal is likely to remain controversial. Some experts have proposed 15 Ma as

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2436-405: The isthmus were Paleo-Indians , who probably arrived between 18 and 15   kya . Since then, the isthmus has been inhabited by Indigenous peoples who have continually developed and adapted to life on the isthmus. The Monagrillo archeological site contains ceramics dating from 2500-1200 BCE, some of the earliest examples of ceramics in Central America. This site also contains evidence of one of

2494-409: The locks on both the Pacific Ocean and Atlantic Ocean ends of the canal and provides via hydro-electric generators about 6 MW of electrical power needed to run the locks and dam. After finishing the dam and filling Gatun Lake it was dredged where necessary to obtain a clear ship channel across the lake. The Gatun location was in most ways ideal for a dam; upstream of the dam site the hills enclosing

2552-503: The most heavily colonized parts of the Isthmus. By 1550, less than three hundred Indigenous people were counted in the cities of Panama, Nombre de Dios, and Nata combined. During the Spanish colonization of Peru , the Isthmus developed into an important port of trade and became an administrative center for the conquests of both South and wider Central America. Silver and gold from the viceroyalty of Peru were transported overland across

2610-420: The normal lake level. The spillway for the dam is constructed on the central hill; it consists of a semi-circular concrete dam, which regulates the flow of water down a concrete channel built into the back slope of the hill. The spillway dam itself measures 225 metres (738 ft) along the top; its crest is at 16 feet (4.9 m) below the normal lake level. The spillway is designed so that water pouring over

2668-656: The northern polar ice cap to form. The creation of the Gulf Stream and the Atlantic system of weather and currents would eventually serve as the environmental engine of the " triangle trade " routes that were the basis of the Atlantic World system in the early modern era. The remains of a variety of paleolithic fauna that were found in the Canal Zone in 2007 include bear-dogs , miniature horses, rhinos, camels, early relatives of modern hippos, and at least one species of chalicothere . The first humans to inhabit

2726-401: The same time widening it considerably, and they had excavated over 76 million cubic metres (100 million cubic yards) of material. Some 23 million m (30 million cu yd) of this material was additional to the planned excavation, having been brought into the cut by the landslides. Gaillard was promoted to colonel in 1913. One month later, on December 5, he died of

2784-445: The semi-circular dam converges at the bottom from opposite directions and neutralises its own force, thus minimising erosion below. The spillway dam is topped by 14 gates, supported by concrete piers and each 14 metres (46 ft) wide by 6 metres (20 ft) high. These gates, which are electrically operated, are raised or lowered to control the flow of water; with the lake level at 26.5 metres (87 ft), its planned maximum level,

2842-442: The shovels to the landfill dumps, about 19 kilometres (12 mi) away. In a typical day, 160 trainloads of material were hauled away from a cut 14 kilometres (9 mi). This workload on the railroads required some skillful co-ordination. At the busiest times, there was a train going inbound or outbound almost every minute. Six thousand men worked in the cut, drilling holes, placing explosives, controlling steam shovels, and running

2900-472: The suitability of the land at Gatun for the building of a large dam there. Extensive test borings were made to determine the suitability of the land, and pressure tests were carried out on the material to be used in construction to determine its durability. The Gatun Dam serves two important purposes: it controls the ever varying Chagres River and creates Gatun Lake. The lake at about 85 feet (26 m) elevation provides an elevated path for ships across most of

2958-486: The trek south across the isthmus. As the connecting bridge between two vast land masses, the Panamanian biosphere is filled with overlapping fauna and flora from both North and South America. There are, for example, over 978 species of birds in the isthmus area. The tropical climate also encourages a myriad of large and brightly colored species, insects, amphibians, birds, fish, and reptiles. Divided along its length by

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3016-461: The valley of the Chagres form a gap just over 2 kilometres (1.2 mi) wide at this point, with a natural rocky hill in the centre of the gap. The gap is filled by an earth dam, 640 metres (2,100 ft) thick at the base, 2,300 metres (7,500 ft) long along the top, 121-metre (397 ft) thick at the water level, and 30-metre (98 ft) thick at the top, which is 9 metres (30 ft) above

3074-466: The work got up to full speed. After reviewing the options and costs, in 1906 a lock-based canal was decided upon and agreed to by President Theodore Roosevelt . Even before the lock canal decision was made, Major George Washington Goethals ( United States Army Corps of Engineers ), the chief engineer from 1907 to 1914 of the construction effort, had already carried out an investigation under John Frank Stevens (chief engineer, 1905–1907) into determining

3132-403: The work was massive. Elaborate (multiple) air compressor facilities using some 30 miles of pipe powered hundreds of compressed air drills to bore holes for 400,000 pounds of dynamite per month to blast and fragment the rock of the cut so that it could be excavated by steam shovels , most made by Bucyrus Foundry and Manufacturing Company of Milwaukee. Dozens of spoils trains took the spoil from

3190-433: Was first noted on October 4, 1907, followed by the mass wasting of about 500,000 cubic yards (380,000 m ) of clay . This slide caused many people to suggest the construction of the Panama Canal would be impossible; Gaillard described the slides as tropical glaciers , made of mud instead of ice. The clay was too soft to be excavated by the steam shovels, and it was therefore largely removed by sluicing it with water from

3248-412: Was in part due to unforeseen oxidation of the underlying iron strata due to water infiltration , which caused weakening and eventually a collapse of the strata. Strain softening of the underlying shale layers of sedimentary units caused continuation of sliding as the strength of the slide post-failure was reduced. The first and largest major slide occurred in 1907 at Cucaracha . The initial crack

3306-428: Was short-lived. The attempt at settling the area did not go well; more than 80 percent of participants died within a year, and the settlement was abandoned twice. The California Gold Rush , starting in 1849, brought a large increase in the transportation of people from the Atlantic to the Pacific. Steamships brought gold diggers from eastern U.S. ports, who trekked across the isthmus by foot, horse, and later rail. On

3364-406: Was the ideal solid base for the construction of the concrete spillway and its dam, the main part of the dam being earth. The only problem was the huge scale of the dam required massive rock and dirt fill that was provided by about 100 trainloads of waste rock deposited into two parallel walls of waste rock about 2,700 feet (820 m) apart every day for several years from the Gaillard Cut (now called

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