By Rosalind Cairncross, P.Eng.
Dreams and Mosquitoes: the Making of the Panama CanalCompanies & People Environmental Engineering Watercourses, Wetlands, Watersheds
For the dreamers of grand engineering projects the challenge was irresistible: to construct a canal across the narrow strip of land between North and South America, a canal which would link the Atlantic Ocean with the Pacific. The long and...
For the dreamers of grand engineering projects the challenge was irresistible: to construct a canal across the narrow strip of land between North and South America, a canal which would link the Atlantic Ocean with the Pacific. The long and dangerous journey via Cape Horn in Argentina would shrink by 8,000 miles. Shipping between the west coast of the Americas and Europe, the east coast and Asia would open up. All that stood in the way was a sliver of land, just 48 miles of it — the isthmus of Panama.
From dreaming to scheming took a few hundred years but the Panama Canal finally opened on August 15, 1914. One hundred years later, its second incarnation, the New Panama Canal is due to open in 2015.
Watching from On Board
Watching the huge container ships clear the Miraflores lock in an astonishingly short time is a marvel. The rail cars bring the ships into the channel and hold them clear of the sides, using cables to secure their position. Once in place, the lock drains 26 million gallons of water into the adjacent lock in 8.5 minutes, lowering the ship. The bell sounds and the gates open, allowing the ship to pass under its own power at a stately 5 miles per hour.
In the course of a passage, water lifts the ships to the level of Gatun Lake 85 ft. above sea level, carries them across the Continental Divide, and lowers them to the ocean again on the other side. All the work is done by gravity acting on water — there are no pumps. And the incessant rain of a rain forest replenishes the water.
On board, seeing the giant gates close behind the ship, the walls of the canal close enough to touch, the lock filling or draining quietly, effortlessly, it is difficult to imagine the state of the world as it was when the Panama Canal was built. Close up both the concrete structure and the riveted gates seem in amazingly good shape for being 100 years old. But the world was very different when building started.
The path to the piece of elegant engineering was long, tortuous, and strewn with major obstacles, which for many were fatal. Overcoming the obstacles took ingenuity and produced numerous innovations in sanitation, infrastructure, excavation processes, equipment, lock and gate design to name a few. It tested the mettle of the profession and produced one of the greatest engineering achievements in human history. And like all projects it started with an idea.
The Dream That Wouldn’t Die
In the early 16th century the Spanish conquerors of South and Central America had shiploads of gold looted from countries like Peru and Ecuador to get back to Spain. The land route through the isthmus was difficult and risky. They dreamed of a sea route, a canal, through the land bridge. They made their case to the king of Spain, who was persuaded. The land was surveyed and a plan following a similar route to the present day canal was drawn up in 1529. But war distracted Spain and the project was moved to the back burner where it simmered for a very long time.
The reports of German scientist and explorer Alexander von Humbolt in the early 19th century turned up the heat. The “wild and mountainous” terrain that he described did little to deter the dreamers. The Spanish government authorized the construction of the canal in 1819. But with all her colonies in South America in revolt, the Spanish again soon had other matters on their minds.
The French Project – Men, Money and the Mighty Mosquito
Decades later, fresh from their most recent engineering triumph with the construction of the Suez Canal, the French were sure that they could build the canal to bridge the Americas. In 1876 they set up an international company with Ferdinand de Lesseps, star of the Suez project, at the helm. De Lesseps was confident that he could “complete the water circle around the world” by building a sea-level canal through Panama.
But a canal through the equatorial forest was a very different proposition from a canal through the sandy desert. The dense vegetation, the rain, the unstable geology, proved to be huge problems. Raising enough money and controlling corruption proved difficult. Finding and keeping men on the project, and keeping them alive, were major battles too.
The French started digging in 1881. Scores of men came from the West Indies. The engineers came from France’s premier engineering schools. The engineers could not be persuaded to stay for any length of time. If they did, they together with thousands of labourers stood to die in droves.Malaria and yellow fever decimated the workforce between 1881 and 1889.
Some 22,000 lives, US $287 million, and 10 years later, de Lesseps gave up. The company was bankrupt and the project had failed amid huge financial scandal.
The American Project
The United States, on the other hand saw an opportunity. In a move that most reports indicate as unmistakable arm-twisting, the Americans coerced the French into selling the canal at the fire sale price of $40 million.
The U.S. also needed the permission of the Colombian government in whose territory the proposed canal lay. The Colombians declined. Not inclined to take “no” for an answer, the Americans instigated a rebellion in the province of Panama which led to its secession. In 1903 the new country of Panama was born, a country friendly to U.S. interests. The two countries signed the Hay-Bunau-Varilla Treaty which gave the Americans sovereignty over a strip of land 10 miles wide, to be known as the Panama Canal Zone. But the Panamanians were never very happy with the terms. Until relatively recently they drew little benefit from the canal. Discontent gave rise to rebellion and treaty after treaty for another century or so.
The Americans had acquired from the French a less-than-half dug ditch, a jumble of buildings, equipment that had rusted in the humid climate, inadequate infrastructure in terms of a railroad to move men, machinery and soil, and a small workforce. There were also good surveys and studies. Some of the excavation and dredging work the French had done would prove useful, and some not.
The U.S. Government set up the U.S. Isthmian Canal Commission which took over the project in 1904. They decided to use locks rather than a sea-level canal and set the US Army Corps of Engineers to build it.
Stevens, Goethals and Gaillard
The first chief engineer, appointed in 1904 with orders from President Theodore Roosevelt to “make the dirt fly,” left one year later after making little progress. Then John Stevens took over in 1905. First he set about dealing with the problems that had undermined the French project: living conditions and disease. To improve living conditions, he built housing, hospitals, churches, schools, recreational facilities, and the infrastructure for the supply and distribution of food.
Fortunately tropical medicine had advanced since the French debacle and the US Army tropical disease expert Walter Reed and a Colonel Gorgas had identified mosquitoes as the disease carriers. With Stevens’ support, Gorgas mounted a campaign to rid the territory of mosquitoes, battling the skeptical army bureaucracy as well. It took strategies ranging from the cultural (persuading Panamanians not to store water in open containers indoors), to the practical (installing wire screens in houses, draining swampland, building concrete ditches and tile drains), to the natural (thousands of minnows and insects to eat mosquitoes), to the chemical (fumigation, spraying standing water with oil), and more to contain the mosquitoes. But they did. Without this victory over the mosquito, there may never have been a Panama Canal. In appreciation of Steven’s support, Gorgas later wrote, “… it is hard to estimate how much sanitation on the Isthmus owes to this gentleman for its subsequent success.”
Stevens also tackled the construction infrastructure. An efficient
railroad was crucial so he built with heavier rolling stock the inadequate railroad inherited from the French and improved all the associated systems…. Then he resigned. His letter to the President complained of political and bureaucratic interference. Apparently President Roosevelt was not amused. He sent an army officer, Colonel George Goethals, to replace him.
Goethals took over as chief engineer in 1907 until its completion in 1914. He would see the construction through some of its most difficult stages: dealing with massive landslides, the completion of the locks and gates. With him was a Major Gaillard who oversaw the blasting and excavation of the difficult 12.5-km Culebra Cut, later renamed the Gaillard Cut. On completion of the canal, Goethals was named Governor of the Panama Canal Zone.
And the Engineering …
The project spawned numerous innovations and many engineering firsts.
Moving mountains of soil was time-consuming, labour intensive and dangerous. Stevens built an effective system of soil excavation and removal (later refined by Geothals) by coordinating steam shovel and train movements. The system kept the soil moving with the efficiency of a conveyor belt as the work progressed.
Blasting and excavating the rocky ridge of the Continental Divide known as the Culebra Cut proved a huge endeavor for Gaillard. Getting to the bottom of the canal meant excavating some 270 feet of mountain. Major landslides halted work for months at a time. Test borings and analysis had determined the quality of the rock, but the effect of rain on the underlying strata of clay and iron pyrites in the rock had been overlooked and its stability was overestimated. The repeated failure of the excavation finally led to the conclusion that the clay could only be removed by water jet from a high level. The crushed rock, however, did help solve another problem. The aggregate would later be used to manufacture concrete for the locks.
The construction of the locks posed a huge challenge. They would be the largest and most advanced in the world. There are three sets: the Gatun, Pedro Miguel and Miraflores. Each is currently 33.5 metres wide. The largest at Gatun is almost 2 kilometres long, and has two parallel sets of three flights that in total lift ships 26 metres.
Each lock has an elegant system of culverts which channel water from a lake. Large culverts run along the centre and side walls of the locks, crisscrossed by smaller ones. When the valves are opened, water enters the large culverts and runs into cross culverts. Holes in the chamber floor allow the water to fill the lock. Valves at either end open or close to admit or shut off the water. The filling and draining of the lock depends entirely on gravity. There are no pumps. The locks are filled from the lakes and drain into the sea level channels, each crossing using 52 million gallons of water. The lakes are replenished by the abundant rainfall.
Dams and Gates
The successful operation of the locks depends on a nearby reservoir, so dams were needed. Building the largest of the lakes, Gatun, required the damming of the Chagres River. Using excavated soil, and rock from the Culebra Cut, the river was dammed by building two walls along its length, filling them with clay which later hardened into an impervious barrier. At the time of construction Gatun Dam and Gatun Lake were the largest earthen dam and artificial body of water in the world. Smaller dams were also built at Pedro Miguel and at Miraflores.
The giant gates that close in a V-shape in front of and behind the ships were considered the greatest technical challenge. They had to move effortlessly, operate dependably and withstand the pressure of the water. And there were no examples to follow.
The easy movement is accomplished by their ingenious construction. The lower half of the gates is hollow and water tight, lightening the load on the hinges. One hundred years later the gates look as sturdy as ever and seem to work effortlessly.
The Canal Opens
Grand festivities were planned for the opening of the canal on August 15, 1914. But it was not to be. The start of the First World War 1 cancelled the party. The first official trip between the Atlantic and the Pacific oceans was made by a ship named SS Ancon.
Despite the lack of fanfare at its opening, the canal was hailed as a marvel of technology. It was the most costly project, in lives and in money, that the U.S. had ever undertaken.
Today the effect on international commerce is clear. Ships of every kind, from smaller boats to huge cruise liners, to ships carrying every kind of freight in containers and specialized vessels, wait to enter the canal. They fly the flags of nearly every country in the world. Some 12,000 ships pass through the canal each year. It takes about 15 hours to travel through. About half of that time is spent waiting.
Over the decades ships have grown so much larger that expansion was the only solution. A $5.2 billion project is being carried out to enable passage to “New Panamax” vessels 55 metres wide. The project is adding two new sets of locks, one on the Pacific and one on the Atlantic sides, as well as creating a new access channel on the Pacific side and dredging the channels. Originally it was to open in 2014, the year of the canal’s 100th anniversary, but the expansion is now set to open in 2015. cce
Rosalind Cairncross, P.Eng., is contributing editor to Canadian Consulting Engineer. She is based in Toronto.