The 20 Dumoulin grapes (including indigenous varieties like Petite Arvine) are nurtured from Clavau, a bisse built in 1453 by the Bishop of Sion. Thanks to its snowy alpine views and direct access to entrance doors (wine bars), the Bisse de Clavau also functions as a hiking route. It is one of a series of fortunately flat bisse walks in the region that have proven to be a boon for regional tourism.
Starting in the village of St-Romain, the 8km Bisse de Clavau road winds through dizzying vineyards that descend to the Rhone River, a strip of sparkling turquoise flanked by emerald green slopes. I followed the sound of the buzzing of bees and the babbling of water flowing alternately through the bisse's open-air concrete channels, stone tunnels, and metal conduits.
One person who knows more about the ancient waterways of the region than most is veteran Jean-Charles Bornet. Raised in the folds of the sun-kissed valley of Nendaz, home to the largest network of bisses in the Valais, the local councilor's happy place is Old Bisse. "I remember walking here as a kid with a huge picnic backpack that weighed more than me," Bornet commented as we followed the contours of the bisse under the towering fir trees. "It's where I spent a lot of weekends, and I still do.
First written in 1640, the 1,600m high Bisse Vieux is unique in transporting water throughout the year, drawn from the Pennine Alps Grand Dรฉsert glacier. It is also a textbook example of how this indigenous irrigation technology was adapted for challenging terrain. Midway along its 7km course, water cascades down a series of staggered metal channels, plunging 5m down to navigate a rocky ridge. On a flatter section, Bornet pointed to the remains of a huge rock that rested on the edge of the bisse, shattered by dynamite. "This was a job for a local apricot farmer who has a dynamite license," he said, explaining that rocks dislodged by melting snow and natural debris such as branches can often clog the bisse, requiring a "explosive" intervention.
Traversing several river basins, longer bisses like the 26 km one in the town of Saxon were an easy target for water thieves in the 1300s. The solution? A water-powered warning hammer, lifted by a paddle wheel at every turn, that still works today. The guards would spend the night in wooden huts next to them, ready to jump if the hammer was silenced, which could also indicate a blockage in the bisse upstream.
