Gaillard Cut
Encyclopedia
The Gaillard Cut, or Culebra Cut, is an artificial valley that cuts through the continental divide
in Panama
. The cut forms part of the Panama Canal
, linking Lake Gatún, and thereby the Atlantic Ocean
, to the Gulf of Panama
and hence the Pacific Ocean
. It is 12.6 km (7.8 mi) from the Pedro Miguel lock on the Pacific side to the Chagres River
arm of Lake Gatun, with a water level 26 m (85 ft) 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 the canal to shipping
, and in particular the strategic interests of the United States of America.
, the excavation of the Culebra 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 metres (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 14,256,000 m³ (18,646,000 cubic yards) of material from the cut, and had lowered the summit from 64 metres (210 ft) above sea level to 59 metres (193 ft), 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
, the American effort started work on a wider, but not as deep a cut, as part of a new plan for an elevated lock-based canal, with a bottom width of 91 metres (300 ft); this would require creation of a valley up to 540 metres (a third of a mile) 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 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 the work was massive. Hundreds of large steam drills bored holes in which were planted tons of dynamite
, which blasted the rock of the cut so that it could be excavated by steam shovel
s. Dozens of spoils trains took the spoil from the shovels to the landfill dumps, about twelve miles (19 km) away. In a typical day, 160 trainloads of material were hauled away from a cut nine miles long (14 km). 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 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, 60 million pounds (27,000 tonnes) of dynamite were used. In some locations, about 52,000 pounds (23.6 metric tonne
s) of dynamite were planted and detonated for 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 landslide
s. The International Board of Consulting Engineers had mistakenly decided that the rock would be stable at a height of 73.5 metres 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. The misjudgment 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.
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
of about 382,000 m³ (500,000 cubic yards) of clay
. This slide caused many people to suggest the construction of the Panama Canal would be impossible; Gaillard described the slides as tropical glacier
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 was removed, resulting in less weight over the weak strata. The slide still continued to cause minor problems after this.
Gaillard died from a brain tumor in Baltimore, Maryland, on December 5, 1913, having been promoted to colonel just one month prior, and hence he never saw 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.
Libraries, USA.
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 connected to the open sea...
in Panama
Panama
Panama , officially the Republic of Panama , is the southernmost country of Central America. Situated on the isthmus connecting North and South America, it is bordered by Costa Rica to the northwest, Colombia to the southeast, the Caribbean Sea to the north and the Pacific Ocean to the south. The...
. The cut forms part of the Panama Canal
Panama Canal
The Panama Canal is a ship canal in Panama that joins the Atlantic Ocean and the Pacific Ocean and is a key conduit for international maritime trade. Built from 1904 to 1914, the canal has seen annual traffic rise from about 1,000 ships early on to 14,702 vessels measuring a total of 309.6...
, linking Lake Gatún, and thereby the Atlantic Ocean
Atlantic Ocean
The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...
, to the Gulf of Panama
Gulf of Panama
The Gulf of Panama is a gulf in the Pacific Ocean, near the southern coast of Panama. It has a maximum width of , a maximum depth of and the size of . The Panama Canal connects the Gulf of Panama with the Caribbean Sea and the Atlantic Ocean...
and hence the Pacific Ocean
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
. It is 12.6 km (7.8 mi) from the Pedro Miguel lock on the Pacific side to the Chagres River
Chagres River
The Chagres River is a river in central Panama. The central part of the river is dammed by the Gatun Dam and forms Gatun Lake, an artificial lake that constitutes part of the Panama Canal. Upstream lies the Madden Dam, creating the Alajuala Lake that is also part of the Canal water system...
arm of Lake Gatun, with a water level 26 m (85 ft) above sea level
Sea level
Mean sea level is a measure of the average height of the ocean's surface ; used as a standard in reckoning land elevation...
.
Construction of the cut was one of the great engineering
Engineering
Engineering is the discipline, art, skill and profession of acquiring and applying scientific, mathematical, economic, social, and practical knowledge, in order to design and build structures, machines, devices, systems, materials and processes that safely realize improvements to the lives of...
feats of its time; the immense effort required to complete it was justified by the great significance of the canal to shipping
Shipping
Shipping has multiple meanings. It can be a physical process of transporting commodities and merchandise goods and cargo, by land, air, and sea. It also can describe the movement of objects by ship.Land or "ground" shipping can be by train or by truck...
, and in particular the strategic interests of the United States of America.
French work
As described in History of the Panama CanalHistory of the Panama Canal
The history of the Panama Canal goes back almost to the earliest explorers of the Americas. The narrow land bridge between North and South America offers a unique opportunity to create a water passage between the Atlantic and Pacific oceans...
, the excavation of the Culebra Cut was begun by a French venture, led by Ferdinand de Lesseps
Ferdinand de Lesseps
Ferdinand Marie, Vicomte de Lesseps, GCSI was the French developer of the Suez Canal, which joined the Mediterranean and Red Seas in 1869, and substantially reduced sailing distances and times between the West and the East.He attempted to repeat this success with an effort to build a sea-level...
, which was attempting to build a sea-level canal
Canal
Canals are man-made channels for water. There are two types of canal:#Waterways: navigable transportation canals used for carrying ships and boats shipping goods and conveying people, further subdivided into two kinds:...
between the oceans, with a bottom width of 22 metres (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
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
in 1904. The French had excavated some 14,256,000 m³ (18,646,000 cubic yards) of material from the cut, and had lowered the summit from 64 metres (210 ft) above sea level to 59 metres (193 ft), over a relatively narrow width.
American work
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
took over on May 4, 1904. Under the leadership of John F. Stevens
John Frank Stevens
John Frank Stevens was an American engineer who built the Great Northern Railway in the United States and was chief engineer on the Panama Canal between 1905 and 1907.- Biography :...
, and later George Washington Goethals
George Washington Goethals
George Washington Goethals was a United States Army officer and civil engineer, best known for his supervision of construction and the opening of the Panama Canal...
, the American effort started work on a wider, but not as deep a cut, as part of a new plan for an elevated lock-based canal, with a bottom width of 91 metres (300 ft); this would require creation of a valley up to 540 metres (a third of a mile) 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 the immense amounts of earthen and rocky spoil.
Major David du Bose Gaillard
David du Bose Gaillard
David du Bose Gaillard was a U.S. Army engineer instrumental in the construction of the Panama Canal.-Biography:He was born in Manning, South Carolina. Gaillard graduated from the United States Military Academy at West Point in 1884. In 1907 he was placed in charge of construction of the central...
, 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
Panama Canal
The Panama Canal is a ship canal in Panama that joins the Atlantic Ocean and the Pacific Ocean and is a key conduit for international maritime trade. Built from 1904 to 1914, the canal has seen annual traffic rise from about 1,000 ships early on to 14,702 vessels measuring a total of 309.6...
— 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
Dynamite is an explosive material based on nitroglycerin, initially using diatomaceous earth , or another absorbent substance such as powdered shells, clay, sawdust, or wood pulp. Dynamites using organic materials such as sawdust are less stable and such use has been generally discontinued...
, which blasted the rock of the cut so that it could be excavated by steam shovel
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. They played a major role in public works in the 19th and early 20th century, being key to the construction of railroads...
s. Dozens of spoils trains took the spoil from the shovels to the landfill dumps, about twelve miles (19 km) away. In a typical day, 160 trainloads of material were hauled away from a cut nine miles long (14 km). 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 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
Dynamite
Dynamite is an explosive material based on nitroglycerin, initially using diatomaceous earth , or another absorbent substance such as powdered shells, clay, sawdust, or wood pulp. Dynamites using organic materials such as sawdust are less stable and such use has been generally discontinued...
were fired daily. In all, 60 million pounds (27,000 tonnes) of dynamite were used. In some locations, about 52,000 pounds (23.6 metric tonne
Tonne
The tonne, known as the metric ton in the US , often put pleonastically as "metric tonne" to avoid confusion with ton, is a metric system unit of mass equal to 1000 kilograms. The tonne is not an International System of Units unit, but is accepted for use with the SI...
s) of dynamite were planted and detonated for a single blast.
Landslides
Landslide
A landslide or landslip is a geological phenomenon which includes a wide range of ground movement, such as rockfalls, deep failure of slopes and shallow debris flows, which can occur in offshore, coastal and onshore environments...
s. The International Board of Consulting Engineers had mistakenly decided that the rock would be stable at a height of 73.5 metres 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. The misjudgment was in part due to unforeseen oxidation of the underlying iron
Iron
Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...
strata
Stratum
In geology and related fields, a stratum is a layer of sedimentary rock or soil with internally consistent characteristics that distinguish it from other layers...
due to water infiltration
Infiltration (hydrology)
Infiltration is the process by which water on the ground surface enters the soil. Infiltration rate in soil science is a measure of the rate at which soil is able to absorb rainfall or irrigation. It is measured in inches per hour or millimeters per hour. The rate decreases as the soil becomes...
, which caused weakening and eventually a collapse of the strata.
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
Mass wasting, also known as slope movement or mass movement, is the geomorphic process by which soil, regolith, and rock move downslope under the force of gravity. Types of mass wasting include creep, slides, flows, topples, and falls, each with its own characteristic features, and taking place...
of about 382,000 m³ (500,000 cubic yards) of clay
Clay
Clay is a general term including many combinations of one or more clay minerals with traces of metal oxides and organic matter. Geologic clay deposits are mostly composed of phyllosilicate minerals containing variable amounts of water trapped in the mineral structure.- Formation :Clay minerals...
. This slide caused many people to suggest the construction of the Panama Canal would be impossible; Gaillard described the slides as tropical glacier
Glacier
A glacier is a large persistent body of ice that forms where the accumulation of snow exceeds its ablation over many years, often centuries. At least 0.1 km² in area and 50 m thick, but often much larger, a glacier slowly deforms and flows due to stresses induced by its weight...
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 was removed, resulting in less weight over the weak strata. The slide still continued to cause minor problems after this.
Completion
Steam shovels broke through the Culebra Cut in May, 1913. The Americans had lowered the summit of the cut from 59 metres (193 ft) to 12 metres (40 ft) above sea level, at the same time widening it considerably, and they had excavated over 76 million cubic metres (100 million cubic yards) of material. Some 23 million cubic metres (30 million cubic yards) of this material was additional to the planned excavation, having been brought into the cut by the landslides.Gaillard died from a brain tumor in Baltimore, Maryland, on December 5, 1913, having been promoted to colonel just one month prior, and hence he never saw 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.
Further reading
Making the Dirt Fly, Building the Panama Canal, Smithsonian InstitutionSmithsonian Institution
The Smithsonian Institution is an educational and research institute and associated museum complex, administered and funded by the government of the United States and by funds from its endowment, contributions, and profits from its retail operations, concessions, licensing activities, and magazines...
Libraries, USA.
- Ira E. Bennett, History Of The Panama Canal.
- TR's Legacy — The Panama Canal, PBSPublic Broadcasting ServiceThe Public Broadcasting Service is an American non-profit public broadcasting television network with 354 member TV stations in the United States which hold collective ownership. Its headquarters is in Arlington, Virginia....
, USA. - Mellander, Gustavo A.; Nelly Maldonado Mellander (1999). Charles Edward Magoon: The Panama Years. Río Piedras, Puerto Rico: Editorial Plaza Mayor. ISBN 1-56328-155-4. OCLC 42970390.
- Mellander, Gustavo A. (1971). The United States in Panamanian Politics: The Intriguing Formative Years. Danville, Ill.: Interstate Publishers. OCLC 138568.