A rare event takes place in 2015: The Lac de Guerlédan is to be drained between April and November 2015!
The Lac de Guerledan is the largest lake in Brittany – it’s an artificial lake and was first flooded around 1930 for electricity production and fresh water supply. In the past it was drained every 10 years or so, but modern maintenance procedures have rendered this unnecessary for the last 30 years – that is until 2015.
In 2015 the lake will be drained and a spectacular drowned valley revealed once more, and probably for the last time for many years as they intend to make it possible to repair the turbines without draining in future.
The result is that by the summer the whole 10 km long lake will reveal its hidden depths (literally). At the bottom runs the Nantes-Brest canal with 17 locks and associated lock-houses seen for the first time for a generation. The pictures in the two videos here were taken in 1985 when the lake was last drained and showed the moonscape of abandoned housed and forests.
The lake will start refilling in November by the natural flow of the Blavet. It will take between six weeks and two months to refill depending on rainfall.
With an area of 400ha and a volume of 51 million cubic metres of water, the lake was last drained in 1985, attracting over 3 million visitors who came to view the submerged locks and houses. The uncontrolled crowds caused blocked roads and parking problems.
This time around the tourist office for the region is planning to avoid these issues. Entry to the bottom of the lake will only be allowed via guided tours, with designated parking and coaches to take visitors to the points of entry.