Val d’Hérens – Grande Dixence Dam

Val d’Hérens – Grande Dixence Dam

At 285 metres in height, Grand Dixence is the tallest gravity dam in the world. Built over a period of 10 years (from 1951 to 1961), this engineering marvel captures the melt waters from some 35 glaciers in the Valais Region to provide hydroelectric power during the high-demand winter months.

While we could have easily taken a nap after our yummy lunch of raclette and wine in the pretty alpine meadow, Mireille hied us on; she had made a reservation for us to take a guided tour of the dam and learn about its construction and maintenance. We would also learn how Switzerland is working hard on conservation to help wean itself from generating electricity using non-renewable sources like imported oil.

After a short drive along another tight, twisty, switchbacked route, we pulled into the parking lot next to the information booth for the dam.

My goodness, we could certainly see why the inhabitants of this region can eat big lunches like we had, and stay so fit. We and another young couple trudged up a steep flight of stairs next to a three-storey building that houses maintenance workers, and summer students who man the information booth and give tours. Then we huffed our way up another steep, switchbacked trail to a building that houses two huge penstocks, which control the water flow though large-diameter pipes leading to turbine generators. It had warmed to 30° C outside, and the cool inside was welcome.

From displays inside the building, we were amazed at how a system of tunnels, pipelines, and pumping stations moves meltwater from smaller collector dams at the bases some of the 35 glaciers (including the Matterhorn about 30 kilometres away) to actually fill the massive impoundment behind the dam. We now realized the 10 years it took involved so much more than just building the dam itself.

Our young guide then took us up another steep flight of stairs into the bowels of the dam itself. As soon as we entered, the temperature dropped to a bone-chilling 6° C. We walked long maintenance tunnels (and climbed more steep stairs) from one side of the dam to the other. Our guide told us about the construction of the dam, indicated where there were sensors to detect movement of the dam itself (since this is a tectonically active area), and showed us air shafts that can be used for escape or rescue. In one gallery deep inside, we watched an introductory film that included the very first work by renowned French-Swiss filmmaker, Jean-Luc Goddard, about the construction of the dam:

The final tunnel led us along a series of instructional displays on wise energy use and conservation. We ended our tour back at the information booth with an official documentary video about the construction of the dam and opening ceremony.

We didn’t have to climb to get to the top of the dam … thank goodness for the aerial cable car!