Monday, November 28, 2011

The Pont du Gard

The Pont du Gard
http://detritusofempire.blogspot.com/2011/11/pont-du-gard.html

If among the many Roman treasures of southern France you had to pick the single most dramatic it would clearly be the Pont du Gard aqueduct.  It has been photographed by many people, most with better cameras and finer aesthetic eyes than mine:

The aqueduct was built mid 1st century AD when Nimes started to outgrow its local water supply.  The Roman engineers found a spring with sufficient capacity some 20 kilometers away, but to take advantage of the contour of the land they plotted a course that ran 50 kilometers.  Remarkably the entire “drop” over that length was only 17 meters!

Much of the course of the aqueduct was underground, but to cross the gorge of the river Gardon a span some 50 meters high was needed.

They built to last… A remarkable state of preservation given the age.  The aqueduct is holding up well too.

The stone projections supported scaffolding for repair work The statistics of this endeavor are stunning.  It took water 27 hours to run from the spring to the final destination at Nimes.  The “drop” over the length of the Pont du Gard proper was 2.5 cm….about an inch.  And it delivered 200,000,000 liters of water a day in its prime.  The Pont du Gard, and its associated aqueduct system survived the end of Roman rule because it still provided essential water.  Indeed, it is felt to have functioned for at least 400 years, and perhaps as long as 800, the variable estimates being based on how long it took dissolved calcium in the water to finally clog the water channel with the equivalent of the scale you find in old pipes.

The Pont du Gard had its challenges over the years, at one point the arches in the second tier were pared down so that horse drawn artillery caissons could cross the bridge.  But with consolidation efforts beginning in the 1700s, and the addition of a pedestrian bridge on the downstream side the Pont was ready to face its greatest challenge.

In 1958 a flood covered the entire lower tier of the Pont du Gard.  As the river is in a narrow gorge the force of water would have been intense.   The Pont du Gard held.  A bridge a few miles downstream constructed with modern technology washed away.

Frontius, a Roman engineer contemporary with this structure is recorded as having said:

“..will anybody compare the Pyramids, or those other useless though much renowned works of the Greeks with these aqueducts, with these indispensable structures?” I
would ask that you pour a libation to the spirit of Frontius and other unknown Roman builders.  In some social settings it is impolite to toast with water, but I am quite sure Frontius would approve.

Tips for a visit.  The site is free, but parking is at a premium and rather expensive.  There is a small but excellent museum on site, it demonstrates the engineering involved in the project.  You will have to hunt for it a little, look to your left as you come up from the entrance to the Pont du Gard.  If you pass the natural grotto in the hillside you have gone too far.  The site can be very crowded at times.  A little peace and quiet, as well as the best views are from upstream.  Walk under the Pont and up onto the river rocks.  If you want a slightly less dramatic section of the aqueduct all to yourself, head for La Pont Rou a couple of kilometers up stream and near the village of Vers.

And still more….