Les Houches Chamonix Wastewater Treatment Plant, Les Houches, France

The Les Houches Chamonix wastewater treatment plant is located in Les Houches, a commune in the Haute-Savoie department of the Auvergne-Rhone-Alpes region in France. Situated in the French Alps near the Mont Blanc massif, the plant serves a population of about 46,295 people, making it a medium-sized agglomeration under EU classification. As a French facility, the plant operates under the EU Urban Waste Water Treatment Directive 91/271/EEC, which requires secondary treatment for agglomerations of this scale. The directive also mandates more stringent treatment if the receiving waters are designated as sensitive areas, which is common in Alpine regions due to the ecological sensitivity of mountain streams and lakes. The plant's treated effluent is discharged into local watercourses that feed into the Arve River, a tributary of the Rhone River. The Rhone ultimately flows into the Mediterranean Sea. This Alpine watershed supports diverse aquatic life and is important for regional biodiversity, including fish species such as brown trout and the endangered European bullhead.

The plant discharges into the Arve River basin, which flows through the Chamonix Valley and joins the Rhone River near Geneva. The Rhone then continues to the Mediterranean Sea. This Alpine watershed is ecologically sensitive, supporting cold-water fish species and serving as a migratory corridor for aquatic fauna. The region's steep terrain and seasonal snowmelt create variable flow conditions that influence pollutant dilution and ecosystem health.