The Panama Canal - the land at Panama

By Richard High29 October 2008

The Isthmus of Panama, only about 80 km wide at its narrowest point, was characterized by mountains, impenetrable jungle, deep swamp, torrential rains, hot sun, debilitating humidity, pestilence and some of the most geologically complex land formations in the world. Most of this was apparent to the explorers and surveyors who explored and measured the land.

What was not obvious was the geological makeup of the land, which is a constant challenge even today. Another was that building a canal across Panama had already defied and defeated the technical expertise of one of the greatest nations on earth.

Low green mountains rising up behind coral shores look benign and inviting. However, unlike most mountain ranges, instead of being formed by folding due to lateral pressure, these mountains were formed by the upward thrust of individual volcanic actions.

Independent formations of different types of hard rock are interspersed and layered between softer rocks and materials in a disorderly and unpredictable patchwork of strata and angles. The Isthmus has also been subjected to several periods of submersion beneath the sea, thus adding cavities of marine materials to the geological mix.

Faults and volcanos

This, in addition to the six major faults and five major volcanic cores in the short distance between Colon and Panama City, adds to the area's geological challenges. Engineers of the time were unaware of this complex Isthmian geology, and perhaps fortunately so, for it might have frightened them off.

Figuring in to the surveyors' difficulties was the tropical rain forest that covered the hilly terrain from base to summit, a density of vegetation nearly incomprehensible to the inexperienced or uninitiated.

Panama's tropical climate, with a temperature averaging 27°C and an annual rainfall of 2.67 m, creates ideal conditions for jungle growth similar to that of Brazil's Amazon jungle. Indeed, the Panama jungle was used as a training ground for US troops sent to Vietnam, as well as for survival training for astronauts going to the moon. This type of jungle must constantly be beaten back or it will resume its ever-forward advance over hard-won clearing.

Flooding, especially of the Chagres River, was another very serious problem. Because of the terrain's precipitous slopes, the heavy rainfall gathers quickly into small streams that flow quickly into the river, causing it to swell at a rapid rate, creating floods. What happens is nicely described in the official words of The Climatology and Hydrology of the Panama Canal:

"Although nearly the entire country, from its headwaters to Alhajuela, is clothed with vegetation, much of which is dense, the slopes are so precipitous, and the rock lies so near to the surface, that severe tropical rain storms convert the precipitous banks of the Chagres into a series of small torrents and cascades, causing the river to rise suddenly and discharge almost inconceivable volumes of water."

On July 19 and 20, 1903, for example, following two days of heavy rains, the Chagres River (normally about 15 m above sea level at Gamboa) rose to 21 m above sea level, and its normal discharge rate of 85 m3 per second increased to more than 879 m3 per second.

Madden (Alhajuela) Dam

French engineers under Mr de Lesseps had been unable to control the Chagres floods, and the American effort did not fully succeed either, until construction in the 1930s of the Madden (Alhajuela) Dam above Gamboa. The French had to periodically endure the disheartening wiping away by flood of bridges and equipment and the re-depositing into the hard-won excavation of tens of thousands of tonnes of earth, rock and debris.

Finally, both malaria and yellow fever were endemic to the Isthmus. For several hundred years, outsiders came to this "Fever Coast," many died from diseases purportedly caused by "miasmal mists" supposedly emanating from swamps and marshes.

"When the trade winds die out, and the hot sultry air of the isthmus ceases to move, a white mist will sometimes rise out of the swelling ocean and hover like a fog over land and sea. The white mist is the precursor of fever and sickness, and those of the isthmus who know remain within doors, unwilling to meet the ghost of the ocean half way. In the early days ... the white mist that rose from the disturbed soil of the isthmus was far more disastrous in its killing effects than the mists of the ocean. It rose from the soil like incense from a brazier. It carried with it from its underground prison all the poison of putrefaction, and wherever it enclosed its victims, there fever and death followed ..."

While it may seem ridiculous today, at the time there were no other, more credible, explanations. In fact, when it was ultimately proven that the bites of insects, namely mosquitoes, carried diseases -- the Stegomyia fasciata for yellow fever and the Anopheles for malaria -- the idea was looked upon as equally preposterous, and proponents of such concepts were soundly ridiculed, such was the state of medical knowledge at the time. Had it been the Americans instead of the French on the Isthmus at the time, they would have suffered similarly.

It can be seen that, in some ways, the French fate on the Isthmus had already been sealed. It may seem incredible to us now to realize the difficulties that had to be endured to proceed towards their goal. Whatever their managerial shortcomings might have been, the valiant French can never be faulted for their courage and determination.

Panama Canal Authority (ACP).

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