12152018Sat
Last updateFri, 14 Dec 2018 4pm

Qanat la Venta 2018 update: It won’t collapse, unless...

If you have a dog-eared copy of the very first version of my book “Outdoors in Western Mexico,” published in 1998, you will find a chapter – deleted in subsequent editions – dedicated to Qanat la Venta, a curious kind of underground aqueduct located ten kilometers west of Guadalajara.

pg8bIt was a system of tunnels we had mistakenly considered for years to be the strangest cave in the world, “with 75 skylight entrances all neatly arranged in a straight line.”

Maybe a year before the publication of that book we brought archaeologist Phil Weigand to the entrance of our mysterious discovery. He took one look and said, “John, your cave is not a cave at all. It’s a man-made structure called a qanat.”

I learned that the original purpose of qanats was to channel water from an underground source through the desert to some spot where water was badly needed. The tunnel was dug by first laying out a straight line route between these two points. Next, workers would dig a series of evenly-spaced vertical access shafts down a precise distance determined by the engineer in charge. Then the holes were connected together underground. The last of these connections – and by far the most dangerous – was to the mother well. If all this was done correctly, the underground channel would have a slope of less than two degrees and the water would slowly make its way down to the far end causing no erosion. All the access holes were then capped with flat rocks, preventing both contamination and evaporation, a serious concern in dry climates.

 

 

pg8a

The Persians claim that they invented the technology for digging qanats 5.000 years ago and quite a successful technology it was, adopted by the Chinese, the Arabs and the Romans and carried to the new world by the Spaniards. In 2016 the Persian Qanat was added to Unesco’s World Heritage list.

In 1731, the city of Guadalajara was literally thirsty for a better water supply after years (centuries, actually) of water shortages. Franciscan Friar Pedro Antonio Buzeta was then hired to solve this problem, which he did by building a network of qanats under the city to bring in water from places like Los Colomos.

Quite possibly, Buzeta’s success inspired the construction of several qanats west of the city, including Qanat la Venta, whose tunnels – which took the form of a giant Y – may have stretched as far as 15 kilometers, carrying water from the base of Cerro el Tepopote and Nextipac to the old Hacienda la Venta, the last stop of stagecoaches before reaching Guadalajara from the northwest.

pg8d

While Fray Buzeta’s qanats in Guadalajara were robustly reinforced with brick, Qanat la Venta was not, and over the years its gentle stream wore away the soft, volcanic-ash floor, creating a narrow passage up to 13 meters tall.

pg8cIn spite of this, the qanat was working well right up to 2004, when newspaper headlines shouted the death of a fireman who was swallowed up by a mysterious collapse near Nextipac. Unfortunately, no one had told the Nextipac farmers and ranchers that the best way to seriously mess up a qanat is by blocking the flow of water through it. So, someone threw trash and rubble down one of the many access holes, damming the water and causing it to rise and soften the walls of the tunnel, resulting in collapses over several years and the needless death of a human being.

pg9a

Shortly thereafter, Protección Civil walled up the entrance to the qanat – without even a plaque honoring this historical site. Fortunately, they thought to install a big steel pipe under the wall to let the water out. This detail was indeed lucky for the people in housing development El Campestre, which now sits right on top of hundreds of meters of forgotten tunnels, just waiting to be remembered. And if ever that flow of water should be blocked, this qanat will surely generate new headlines.

Last week I went to visit the 75-meter bit of the qanat which is still accessible. Here you stand 20 meters below the surface in a room 17 meters wide. This passage is imposing, and so is the huge, intimidating, cinder-block wall now blocking access to the rest of venerable Qanat la Venta.

Unfortunately, the qanat entrance lies on private land and access to the public is forbidden. The best I can offer as a substitute is a PowerPoint presentation I have made all about this curious vestige of Jalisco’s history, which I will be happy to show to any group interested. There are several interesting twists and turns in this tale.

In fact, I’d say it’s a slide show that you simply qanat afford to miss!

No Comments Available