Le pont Du Gard
Unesco World Heritage site, well know, well protected, magnificent in its ambition as well as its execution, a thing of architectural and artistic beauty and longevity - but in essence only a 274m means to an end in a 50km aqueduct carrying water from Uzès to Nîmes.
They had to cross the Gardon somehow!
But what of the other 49.726km, stretching from la Fontaine de l'Eure in Uzès to le Castellum in Nîmes, using the barest of vertical drops of only 12.183m in total over that distance?
L’aqueduc de Nîmes
The route, from its origin in la vallée de l’Eure in Uzès to the distribution point at le Castellum in Nîmes, begins with a collection basin and infrastructure, passes through a regulation basin (the first of several), where the flow could be delayed, halted or redirected into l’Alzon river, continues over relatively level terrain as it leaves Uzès, until it eventually approaches le Gardon’s Rive Gauche. The key is ‘relatively’: given the need to maintain a gradient over the 50km length and having only 12m to play with, even here the route must travel in places at ground level, in others half-buried; yet others require the channel itself to be raised, buried or tunneled, streams to be bridged, culverts to be built, corners to be turned.
All of these efforts are belittled by the difficulty of the terrain on la rive droite. Having crossed le Gardon via the magnificent pont du Gard, the route traverses, over its next four or five kilometres, no less than 11 valleys (or vallons, combes), each one requiring a bridge of greater or lesser complexity, and each one requiring a route that follows the contours of the valleys to maintain the gradients. The terrain here is much more difficult, even to modern walkers with something to follow. The trail peters out, reappears, passes through dense undergrowth, and often offers no guidance. It eventually debouches near Remoulins, where it takes a long wander around the valley that separates Remoulins from Saint Bonnet du Gard, before arriving at the tunnels of Sernhac, hollowed out from one of the limestone quarries used in the construction of the aqueduct.
At that point, having navigated the immovable obstacle of le Garrigues de Nîmes that lies between le pont du Gard and Nîmes, the channel returns to the plain for its final run in to le Castellum.