Lac Brenet

Lac Brenet is a small lake in the Swiss canton of Vaud, right beside the village of Le Pont in the Vallée de Joux, high in the Jura mountains. Its surface lies at 1,002 m above sea level, just 200 metres north of the much bigger Lac de Joux.

What is Lac Brenet?

The lake covers roughly 0.8 km², stretching about 1.5 km in length and up to 500 m across, with a maximum depth of 18 m. The Vallée de Joux has no surface outlet, so for centuries the water drained away through underground fissures and resurfaced at the source of the Orbe river. Today Brenet also serves as a reservoir for the hydroelectric plant at Vallorbe, which means its level fluctuates.

How does it relate to Lac de Joux?

Only a narrow strip of land separates the two lakes, and Brenet sits 2 m lower. They were once linked freely by the Orbe. A study by Eawag for the canton of Vaud found that over a little more than a century Joux lost about a quarter of its volume and Brenet about a third, because hydropower operation lowered water levels by 4 and 6 m. Changed flow patterns have left the two basins completely disconnected. Fishing rules place the boundary between them at the Joux sluice gate.

What can you see and do?

• Walk the shoreline and take in the forested slopes of the valley, far from the crowds of the big Alpine resorts.
• Watch birds and wildlife by the water, using Le Pont as an easy base.
• Fish: a 2011 inventory confirmed five historically recorded species in the two lakes: trout, perch, burbot, pike and a cyprinid. Federal law and Vaud cantonal regulations apply, so check the permit you need before you go.
• Pair the visit with Lac de Joux next door, the better base for a longer stay in the valley.

How do you get there?

Le Pont, set between the two lakes, is the most convenient starting point. The valley lies in the Swiss Jura in the heart of Vaud, and roads and rail approach it from the Vallorbe side. From the lakeside villages you reach the water on foot.

When should you go?

At over 1,000 m the summers are cool and the winters long, so the warmer months are the most pleasant for lakeside walks. Water levels rise and fall with reservoir management, which changes the look of the shore.

Frequently asked questions

Is Lac Brenet a natural lake?

Yes, it is a natural lake that is also used as a reservoir for the hydroelectric plant at Vallorbe.

How far is Lac Brenet from Lac de Joux?

About 200 metres of land lie between them. Brenet is to the north and 2 m lower.

How deep is Lac Brenet?

The maximum depth is about 18 m, over a surface of roughly 0.8 km².

Can you fish there?

Yes, subject to federal and cantonal rules and permits. Trout, perch, burbot and pike are among the species present.