Panama fever (79 page)

Shovels started cutting a channel through Spillway Hill while suction dredges thoroughly cleaned out the old river and canal beds. Then two parallel lines of trestles were erected at 30 feet above sea level along the upriver and downriver faces of the dam some 4,000 feet apart. On these were laid rail tracks to carry cars of rocks to create the two stone “toes” that would hold the innards of the dam in place. Locomotives from Culebra or the Mindi Hills started arriving regularly and slowly the rock walls began to crawl across the wide valley. Meanwhile a suction dredge began pumping in between the walls a mixture of clay and water sucked up from the bed of the old French canal behind the dam site. Toward the end of 1908 a solid wall of rock, 60 feet high, had been laid out along the extremities of the dam.

Back in the States, the doubters were still vociferous, and now Bunau-Varilla had added his comments: water would seep through, emptying the lake, he said; the dam should have been located at Bohío (as per the French lock plan), where there was better bedrock; Gatún Dam would develop fissures and would be damaged by even a light earthquake. Then, at end of November came the news that everybody had been dreading. “Collapse of the Gatún Dam” read one headline in the United States. “Chagres River plunges through Gap in Isthmian Wall.” It turned out that an American journalist in Panama had noticed that a large section of the southern “toe,” some 200 feet, had slipped by 20 feet where it crossed the line of the old French canal. Goethals denied any serious problem and was backed up by John Stevens, who wrote an article denouncing “the outbreak of yellow fever journalism in regard to the Gatún Dam.”

But with their predictions of doom seemingly confirmed, the press kept the story running. The
New York Times
, a longtime enemy of Roosevelt and his Panama route, declared that the canal had to be begun anew at Nicaragua. Taft was quickly dispatched to Panama with some experts in tow to find out the truth about the dam. He confirmed Goethals's line that the slip was not serious, and rounded on critics of the great project, accusing them of creating a “fire in the rear… calculated to break down the nervous system of those persons on the Isthmus working day and night, tooth and toenail to build the greatest enterprise of two centuries.”

The damage to the “toe” was repaired, and early in 1909 the first concrete was poured at the spillway site. Throughout the year, the massive dam structure began to take shape, rising to block the valley. By the end of 1910 four dredges and more than ten locomotives were at work, adding between them over a million cubic yards a month to the mass of the dam. As the new chasm was being created in the Cut, much of the spoil removed ended up as the new mountain at Gatún. The peak year of building was 1911, when there were two thousand men at work and over a hundred trainloads of rock and earth were being dumped every day. There were further alarms: in October 1911, 1,000 feet of the dam's eastern end settled a few feet, and in August the following year about 800 feet of the crest of the dam dropped 20 feet. On other occasions, as with the walls of the Cut, the dam writhed and twisted as it sought a new equilibrium, wrecking track and threatening the lives of the locomotive drivers. But these were largely movements within the fill, rather than a slip of the entire structure, and as the clay center of the dam dried out and hardened, so the period of greatest danger passed.

With the Panama Railroad relocated on higher ground, it was time to start filling the new lake. At the end of April, preparations were complete for the closing off of the West Diversion. The engineers knew that the final taming of the Chagres River would not be easy. For one thing, delays meant that the river level was 7 feet above its lowest dry-season level, and more rains were on the way. Furthermore, the West Diversion ran directly over a deep gorge, with mud to great depths. It was also about 20 feet lower than the bottom of the spillway, through which the river was now to be directed. This meant that the river would need to rise by this height before it would begin to find the new outlet.

Huge trestles were driven into the mud of the channel, and hundreds of flatcars, loaded with rock from Culebra, were readied nearby. The plan was simply to unload the rock into the current faster than it could be washed away.

Starting at either side, rocks were dumped from the trestles around the clock for four days. Initially, all was fine, but as the channel contracted, the flow picked up power and pace. When it had shrunk to 80 feet wide and 6 feet deep, as fast as the spoil was dumped it was washed away. Even rocks weighing a ton were lifted up and carried off by the powerful Chagres current. A great mass of old twisted French rails was brought up to the site and thrown off the trestle into the open section. As predicted, the rails snarled on the trestle piles, forming a web that started to catch and hold the bigger rocks. But this also transferred huge pressure onto the trestle itself, which groaned and trembled, then broke, with parts starting to move downstream. The water rushed through again, and parts of the surviving dam slid and collapsed.

But the battle was not lost. Men clambered out onto the trestles to repair them, more cars were brought up frantically to dump rock, and a dredge started pumping clay upstream of the dam breach to reduce the force on the trestles. Finally the dam held, and as the water at last found the outlet of the heavily regulated spillway, the destructive force of the Chagres, the bane of the French effort, was gone forever.

With the West Diversion closed, the water was allowed to back up and the lake began to rise at 2 inches a day. Eventually the water would cover 164 square miles of jungle, as well as several villages and much of the digging of the French. Some villagers refused to move out and had to be forcibly evicted. For many of them the drowning of the Chagres valley was like a biblical flood. A way of life based on the river, which long predated Columbus's first voyage, was coming to an end. “It is not hard to realize why the bush native does not love the American,” wrote Harry Franck, who took a trip out on the growing lake in a police launch in mid-1912. “Suppose a throng of unsympathetic foreigners suddenly appeared resolved to turn all the world you knew into a lake, just because that absurd outside world wanted to float steamers you never knew the use of, from somewhere you never heard of, to somewhere you did not know.”

he first task in constructing the locks had been to excavate to bedrock the basins in which they were to be built. For Gatún, this meant digging a hole a mile and a quarter long, 200 yards wide, and 50 feet deep—the removal of nearly 7 million cubic yards of rock and silt. Most difficult was the lowest of the three basins, whose bottom was 66 feet below sea level, and whose sides constantly slipped. As the engineer in charge wrote, “No one expected on returning to work in the morning to find things as they were left the evening before.” Even though there were temporary dams at both ends of the lock basins, there was a constant danger of seepage and floods. American Harry Cole worked on the locks on the Pacific side—one pair at Pedro Miguel, two at Miraflores. In the lowest basin on the Mi-raflores locks—”an extremely dangerous place to work”—he experienced the same problems. “Sometimes, in the rainy season,” he wrote, “even the small rivers became large rivers and often overflowed and inundated much of the construction work, putting even our drainage pumps out of action. Canal banks would break loose, cover up lock wall foundations, fill up culverts, submerge railroad service tracks and cause weeks of delay to clean up and put the work in order again. Those were our heart-breaking times.”

As excavation continued on the lower basins, in late 1909 actual construction started on the completed upper basin of the Gatún Locks. The lock component of the 1906 plan had attracted almost as much criticism as the dam. Certainly, the locks were a gamble. Nothing of the sort even remotely as large had been built before, and the choice of concrete as the primary building material, mainly to save time, was even more daring. Today, concrete technology is an industry in its own right, as it can be a more difficult material to work with than it first seems. In the early 1900s little was known about the properties of concrete and the basic materials (sand, gravel, cement, and water) were simply thrown together in a fairly fixed proportion, mixed, and poured. That the locks at the Panama Canal are still working nearly a hundred years later without any major problem in the concrete is testament to the standard of design and construction employed.

The structural design of the locks was unremarkable. They were to be constructed of “mass concrete,” that is, there was to be little use of steel reinforcement bars. This type of structure, like the Gatún Dam, relies mainly on the enormous mass of material present to withstand the loads imposed upon it. In fact, the sidewalls of the locks are structurally similar to miniature dams. The massive width of the bottom of the wall, some 50 feet, creates an equally large frictional resistance to the force of the water pushing against it when the lock is full. The wall becomes thinner and thinner as the height increases and the applied hydraulic force reduces.

The key to building a major concrete structure was the same as that for the excavation works at the Cut: creating an organized and balanced production line. In this, Goethals was equally as successful at the locks as Stevens had been in the Culebra Cut. To build any concrete structure, the wet concrete must be poured into giant “molds,” referred to as shutters. Traditionally, these are made of wood. In massive structures such as the Panama locks, using wood becomes extremely wasteful, time-consuming, and thus expensive, as the molds can only be used two or three times before being scrapped. Goethals therefore opted to use shutters made of steel, which has a very high initial cost, but a relatively low total lifetime cost. Such a shutter weighed many hundreds of tons and constituted a major feat of precise manufacture in itself. These main shutters were then mounted on rails, running parallel to the walls, so that they could be easily moved.

An enormous amount of concrete was required. For the Gatún Locks alone, 2 million cubic yards would be poured. The cement came from the States, about five million bags or barrels of it. Obviously it made sense to source the stone and sand from nearer to the site. The Commission sent a party to try to secure sand from San Blas, which although ninety miles from Colón, had the best quality for cement. But this area was inhabited by Cuna Indians, who had long memories: “They did not look with favour on visits from the white men, whom they suspected were searching not for sand but for gold,” reported one of the engineers. The Americans were led before a seventy-year-old local chief, “seated on a block of timber, and he motioned his visitors to a seat on the sand at his feet. An air of great solemnity surrounded the proceedings.” The visitors outlined their plans to connect the two oceans by a canal, and how this would bring a better price for the Indians’ coconuts and ivory. “The Chief listened,” the account continues, “but when the story was finished he said that God had given the Indians their country, the land and the water, and that which God had given to the Indians they would neither sell or give to the white man.” That was his final word, and permission to anchor for the night was only granted on the condition that the Americans left the next morning and did not return. So the rock for the gravel, including old stones from the fortress of San Felipe de Todo Fierro, ended up coming from Portobelo, where a crushing plant was built, and the beach at Nombre de Dios was stripped of its sand, all to feed the voracious appetite of the Gatún Locks. On the Pacific side suitable rock and sand were found much closer to the lock sites, but to supply Gatún required barges negotiating the dangers of a sea journey of between twenty and forty miles. Any stoppages from bad weather would upset the brilliant mechanized system Goethals had now established to deliver the mixed concrete to where it was needed. Once the barges from up the coast arrived at Colón, they made their way up the newly redredged old French canal to Gatún, where unloading facilities and a mixing plant had been established. The concrete was assembled by the use of an ingenious system of small electric cars carrying buckets passing under hoppers containing sand, crushed stone, or cement. These would end up above one of the eight giant mixers, underneath which other similar cars waited for the finished concrete.