That the Mayan developed an effective route between the Pacific and the Caribbean should not be surprising. There were obviously goods needing such access and finding and improving such a route would be attractive to any organized polity nearby.
Besides, Central America is a mountain spine in which all bulk goods end up on the coast for transshipment anyway. A linked riverine system would be well known and exploited early.
Whether any polity was organized enough to seriously improve it is an interesting question. What goods would justify the effort?
I have always thought hydraulic engineering to be largely obvious, but never built unless driven by ample traffic and economic incentives. The Isthmus of Corinth was an excellent example of this. The value of a canal was always obvious, but traffic was always low enough to make portaging competitive for most of history.
In any event, this particular connection would obviously require a modest effort to provide easy movement. A few ditches possibly and it becomes easy to traverse. And if anything were to prove difficult, it seems a simple portage will suffice.
It is definitely a local proposition though.
Explorer finds evidence of early waterway from Atlantic to Pacific
Valentine Low
February 13, 2010
Hailed by some as the eighth wonder of the world, the Panama Canal is one of the greatest engineering achievements. It took more than 20 years and cost the lives of more than 27,000 workers. It was the culmination of a dream that began more than 400 years earlier to create a water passage between the Atlantic and Pacific.
But was it really the first? An explorer claims to have found evidence of another, more ancient, water route between the oceans — one that existed hundreds of years before the Panama Canal was conceived.
Several hundred miles to the north-west, in Nicaragua, the route — which involves rivers, a lake and flood plains — was discovered by Colonel John Blashford-Snell, who has just returned from an expedition there.
“It is tremendously exciting,” said the veteran explorer. “With effort it is navigable. But it is going to need more investigation.” He is now planning another expedition to discover whether it is really possible to take a boat from one coast to the other without touching land.
If so, it will prove something remarkable: that the ancient maps which show a passage between the two oceans — and which have long been dismissed as fanciful — had a greater claim to accuracy than was realised.
A 1774 map by Thomas Kitchin, for example, appears to show a channel that would allow boats to pass between the oceans.
Colonel Blashford-Snell’s expedition set out to find evidence that a canal once existed in Nicaragua, part of a wider — and more far-fetched — theory by the writer Gavin Menzies that the Chinese landed in America long before Columbus.
No records of such a canal exist, although there were plans for a Nicaragua canal before the argument for Panama
Whether Colonel Blashford-Snell found evidence of ancient canals is arguable — he does not push the point himself — but the case for a natural water passage is strong, according to the explorer.
Parts of the passage are well known, if not obviously navigable. Lake Nicaragua, which is 100ft (32m) above sea level, occupies the central part of the isthmus, and from there the San Juan River runs east to the Caribbean .
Rapids make the upper parts of the river hard to navigate, although in 1780 a young Horatio Nelson ventured upstream to lead an assault on a Spanish fort on the river.
“It is said that the pirate Henry Morgan came up from the Caribbean three times in 12m boats,” said Colonel Blashford-Snell. “When he got to the rapids, he got round them by pulling the boats.
“Then they rowed across the lake, sacked the city of Granada and then retired back to the Caribbean with their loot.”
Getting from the lake to the Pacific seemed to be a greater challenge, even though it is a distance of only 12 miles (19km) at its shortest.
Colonel Blashford-Snell, who spent two weeks in Nicaragua last month with a team of four, said he found places where the head waters of different river systems — one flowing east into the lake, another flowing west into the Pacific — were only a few hundred yards apart. The seemingly unanswerable question, however, was how to get from one river to the other.
Then, by chance, he met a local fisherman who helped him to unlock the puzzle. Mariano Hernandez told them he had made the journey from the centre of the isthmus between Lake Nicaragua and the Pacific down to the lake to go fishing — a journey made possible during the rainy season when the land turns into a lake up to 2m deep.
“He said he built a 3m canoe out of cedar wood and did the journey with his brother. They had one nasty capsize and also had a very nasty shock when a bull shark appeared alongside. But they did the journey three times,” said Colonel Blashford-Snell. The fisherman also said he had made the journey west to the Pacific on another river. According to the explorer, other villagers corroborated the fisherman’s story.
“It seems likely that even if early cartographers did not see this lake, they were told about it by the indigenous people, and thus drew a channel on their maps,” said Colonel Blashford-Snell. “I’m sure this is how the story of the legendary route between the oceans started.”
