Lac d'Altenweiher, reservoir in France

Lac d'Altenweiher is a small reservoir in the Mittlach valley near Metzeral, surrounded by forests and mountain peaks. Clear water and walking paths circle the lake, offering views of the surrounding landscape.

The dam was built between 1886 and 1893, while Alsace was under German administration, on the site of a former peat bog now submerged; it first held water in 1894. From the late 19th century it fed the Fecht in summer so the river would not run dry, and held back winter floodwater to limit flooding in the Munster valley. Fed by the Solrunz, it drains through the Altenweiherrunz into the Kolbenfecht.

The lake's name reflects the region's Germanic heritage and cultural connections. Visitors can observe how locals use this space for everyday leisure, gathering for walks and simple outdoor meals.

The lake is easily reached by car or bike from Metzeral with parking available near the entrance. Walking paths are gentle and safe for families, with rest benches positioned along the route.

The lake surface freezes over in colder months, creating a smooth white contrast against the dark peaks surrounding it. In spring and summer, wildflowers bloom along the edges and attract butterflies and birds.