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The Culebra Cut, formerly called Gaillard Cut, is an artificial valley that cuts through the
Continental Divide A continental divide is a drainage divide on a continent such that the drainage basin on one side of the divide feeds into one ocean or sea, and the basin on the other side either feeds into a different ocean or sea, or else is endorheic, not c ...
in
Panama Panama ( , ; es, link=no, Panamá ), officially the Republic of Panama ( es, República de Panamá), is a transcontinental country spanning the southern part of North America and the northern part of South America. It is bordered by Cost ...
. The cut forms part of the Panama Canal, linking
Gatun Lake Gatun Lake ( es, Lago Gatún) is a large freshwater artificial lake to the south of Colón, Panama. At approximately above sea level, it forms a major part of the Panama Canal, carrying ships of their transit across the Isthmus of Panama. Gatu ...
, and thereby the Atlantic Ocean, to the
Gulf of Panama The Gulf of Panama ( es, Golfo de Panamá) is a gulf of the Pacific Ocean off the southern coast of Panama, where most of eastern Panama's southern shores adjoin it. The Gulf has a maximum width of , a maximum depth of and the size of . The Pana ...
and hence the Pacific Ocean. It is from the Pedro Miguel lock on the Pacific side to the Chagres River arm of Lake Gatun, with a water level above
sea level Mean sea level (MSL, often shortened to sea level) is an average surface level of one or more among Earth's coastal bodies of water from which heights such as elevation may be measured. The global MSL is a type of vertical datuma standardised ...
. Construction of the cut was one of the great
engineering Engineering is the use of scientific principles to design and build machines, structures, and other items, including bridges, tunnels, roads, vehicles, and buildings. The discipline of engineering encompasses a broad range of more speciali ...
feats of its time; the immense effort required to complete it was justified by the great significance of the canal to
shipping Freight transport, also referred as ''Freight Forwarding'', is the physical process of transporting commodities and merchandise goods and cargo. The term shipping originally referred to transport by sea but in American English, it has been ex ...
, 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 David du Bose Gaillard (September 4, 1859 – December 5, 1913) was a U.S. Army engineer instrumental in the construction of the Panama Canal. During the years of the US Canal Zone (c. 1915–2000), the Culebra Cut in the Panama Canal bore h ...
, who had led the excavation. After the canal handover to Panama in 2000, the name was changed back to ''Culebra''. In Spanish the cut is known as the Corte Culebra and is also called the Snake Cut.


Construction


French work

The excavation of the cut was begun by a French venture, led by
Ferdinand de Lesseps Ferdinand Marie, Comte de Lesseps (; 19 November 1805 – 7 December 1894) was a French diplomat and later developer of the Suez Canal, which in 1869 joined the Mediterranean and Red Seas, substantially reducing sailing distances and times ...
, which was attempting to build a sea-level
canal Canals or artificial waterways are waterways or engineered channels built for drainage management (e.g. flood control and irrigation) or for conveyancing water transport vehicles (e.g. water taxi). They carry free, calm surface fl ...
between the oceans, with a bottom width of 22 meters (72 ft). Digging at Culebra began on January 22, 1881. A combination of disease, underestimation of the problem, and financial difficulties led to the collapse of the French effort, which was bought out by the United States in 1904. The French had excavated some of material from the cut, and had lowered the summit from 64 meters (210 ft) above sea level to 59 meters (193 ft), over a relatively narrow width.


American work

The United States took over on May 4, 1904. Under the leadership of John F. Stevens, and later
George Washington Goethals George Washington Goethals ( June 29, 1858 – January 21, 1928) was a United States Army General and civil engineer, best known for his administration and supervision of the construction and the opening of the Panama Canal. He was the State ...
, 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 Lock(s) may refer to: Common meanings *Lock and key, a mechanical device used to secure items of importance *Lock (water navigation), a device for boats to transit between different levels of water, as in a canal Arts and entertainment * ''Lock ...
-based canal, with a bottom width of ; this would require creation of a valley up to wide at the top. A vast amount of new earthmoving equipment was imported, and a comprehensive system of
railway Rail transport (also known as train transport) is a means of transport that transfers passengers and goods on wheeled vehicles running on rails, which are incorporated in tracks. In contrast to road transport, where the vehicles run on a prep ...
s was constructed for the removal of the immense amounts of earthen and rocky
spoil Spoil or spoils: *Plunder taken from an enemy or victim *Material (such as rock, earth or other overburden) removed during: ** excavation **mining **dredging *An Australian rules football tactic, see One percenter (Australian rules football)#Spoil ...
. Major
David du Bose Gaillard David du Bose Gaillard (September 4, 1859 – December 5, 1913) was a U.S. Army engineer instrumental in the construction of the Panama Canal. During the years of the US Canal Zone (c. 1915–2000), the Culebra Cut in the Panama Canal bore h ...
, of the
U.S. Army Corps of Engineers , colors = , anniversaries = 16 June (Organization Day) , battles = , battles_label = Wars , website = , commander1 = ...
, 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 The Panama Canal locks ( es, Esclusas del Canal de Panamá) are a lock system that lifts ships up to the main elevation of the Panama Canal and down again. The original canal had a total of six steps (three up, three down) for a ship's passage. ...
— most notably, the Culebra Cut. Gaillard brought dedication and quiet, clear-sighted leadership to his difficult, complex task. The scale of the work was massive. Hundreds of large steam drills bored holes in which were planted tons of
dynamite Dynamite is an explosive made of nitroglycerin, sorbents (such as powdered shells or clay), and stabilizers. It was invented by the Swedish chemist and engineer Alfred Nobel in Geesthacht, Northern Germany, and patented in 1867. It rapidly g ...
, which blasted the rock of the cut so that it could be excavated by
steam shovel A steam shovel is a large steam-powered excavating machine designed for lifting and moving material such as rock and soil. It is the earliest type of power shovel or excavator. Steam shovels played a major role in public works in the 19th and e ...
s, most made by Bucyrus Foundry and Manufacturing Company. Dozens of spoils trains took the spoil from the shovels to the landfill dumps, about away. In a typical day, 160 trainloads of material were hauled away from a cut . 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 the dirt trains. They also moved and extended the
railroad track A railway track (British English and UIC terminology) or railroad track (American English), also known as permanent way or simply track, is the structure on a railway or railroad consisting of the rails, fasteners, railroad ties (sleepers ...
s 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, of dynamite were used. In some locations, about of dynamite were planted and detonated for a single blast.


Landslides

The excavation of the cut was one of the greatest areas of uncertainty in the creation of the canal, due to the unpredicted large
landslide Landslides, also known as landslips, are several forms of mass wasting that may include a wide range of ground movements, such as rockfalls, deep-seated slope failures, mudflows, and debris flows. Landslides occur in a variety of environments ...
s. The International Board of Consulting Engineers had mistakenly decided that the rock would be stable at a height of with a slope of 1 in 1.5; in practice, the rock began to collapse from that slope at a height of only . The misjudgment was in part due to unforeseen
oxidation Redox (reduction–oxidation, , ) is a type of chemical reaction in which the oxidation states of substrate change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is the gain of electrons or a d ...
of the underlying
iron Iron () is a chemical element with symbol Fe (from la, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, right in fr ...
strata due to water infiltration, which caused weakening and eventually a collapse of the strata. Strain softening of the underlying
shale Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4) and tiny fragments (silt-sized particles) of other minerals, especially ...
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 was first noted on October 4, 1907, followed by the
mass wasting Mass wasting, also known as mass movement, is a general term for the movement of rock or soil down slopes under the force of gravity. It differs from other processes of erosion in that the debris transported by mass wasting is not entrained in ...
of about of
clay Clay is a type of fine-grained natural soil material containing clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4). Clays develop plasticity when wet, due to a molecular film of water surrounding the clay parti ...
. This slide caused many people to suggest the construction of the Panama Canal would be impossible; Gaillard described the slides as tropical
glacier A glacier (; ) is a persistent body of dense ice that is constantly moving under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires distinguishing features, such as ...
s, 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 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.


Completion

Steam shovels broke through the Culebra Cut on May 20, 1913. The Americans had lowered the summit of the cut from to above sea level, at the same time widening it considerably, and they had excavated over of material. Some 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 a
brain tumor A brain tumor occurs when abnormal cells form within the brain. There are two main types of tumors: malignant tumors and benign (non-cancerous) tumors. These can be further classified as primary tumors, which start within the brain, and seconda ...
in
Baltimore Baltimore ( , locally: or ) is the most populous city in the U.S. state of Maryland, fourth most populous city in the Mid-Atlantic, and the 30th most populous city in the United States with a population of 585,708 in 2020. Baltimore was ...
, 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. Executive Order 2185 After the handing over of the canal to Panama in 2000, the old name ''Culebra Cut'' was reinstated.


See also

*
Postage stamps and postal history of the Canal Zone Postage stamps and postal history of the Canal Zone is a subject that covers the postal system, postage stamps used and mail sent to and from the Panama Canal Zone from 1904 up until October 1978, after the United States relinquished its authori ...
*
Earthworks (engineering) Earthworks are engineering works created through the processing of parts of the earth's surface involving quantities of soil or unformed rock. Shoring structures An incomplete list of possible temporary or permanent geotechnical shoring structur ...


References


Further reading

*
Making the Dirt Fly, Building the Panama Canal
',
Smithsonian Institution The Smithsonian Institution ( ), or simply the Smithsonian, is a group of museums and education and research centers, the largest such complex in the world, created by the U.S. government "for the increase and diffusion of knowledge". Founded o ...
Libraries, USA. *Ira E. Bennett,
History Of The Panama Canal
'.

,
PBS The Public Broadcasting Service (PBS) is an American public broadcaster and non-commercial, free-to-air television network based in Arlington, Virginia. PBS is a publicly funded nonprofit organization and the most prominent provider of educati ...
, USA.


External links


Photos of the Culebra Cut in the Panama Stereographs CollectionImage of the Cucaracha Slide
{{Coord, 9, 4, 38, N, 79, 40, 31, W, type:landmark, display=title Cuts (earthmoving) Panama Canal 1913 establishments in Panama