Lac de Chaumeçon, Reservoir in Brassy, France.

Lac de Chaumeçon is an artificial lake on the Chalaux in the Nièvre department, within the Morvan regional natural park. Its 135-hectare surface, holding up to 19 million cubic metres, lies at an elevation of 400 m near the commune of Brassy. The water is bordered by dense green foliage and meets a low wooded ridge at its far edge.

The lake was created between 1931 and 1933 when a dam flooded the valley, establishing a water storage system for regional needs. This engineering project permanently altered the landscape and became a key part of the area's water management.

The lake is fed by the Chalaux and lies within the Morvan Regional Natural Park. Kayaks and stand-up paddles can be rented near the Chaumeçon dam, and swimming and fishing are allowed more than 500 m from the dam. The reservoir holds up to 19 million cubic metres of water.

Lac de Chaumeçon lies on the Chalaux in the Nièvre, next to Brassy, at an elevation of 400 m. Swimming and fishing are allowed only more than 500 m from the dam. Tourist sit-on-top kayaks and paddles can be hired near the dam, at Angie kayak. Water is stored from October to June and released from July to September, so levels vary through the year.

The dam holds back up to 19 million cubic metres of water, stored from October to June to limit flooding on the Yonne and Seine, then released between July and September. Kayaks and stand-up paddles can be hired near the dam, and swimming and fishing are allowed more than 500 m from it.