Lac de la Ganguise, Artificial reservoir in Belflou, France

Lac de la Ganguise is an artificial reservoir that covers about 278 hectares across five communes with two distinct arms that converge at the northwestern section. The lake has a varied shoreline and multiple access points for visitors exploring the water.

The Ganguise was dammed in 1979 with an earth dike closing the whole valley, a scheme first proposed in 1951. The reservoir was built for farm irrigation and originally covered 278 hectares. In 2007 the dike was raised three metres, doubling capacity and extending the water to Cumiès, bringing the surface to 500 hectares.

The lake's name comes from the Ganguise, the Hers-Mort tributary dammed to create it; it is also called Retenue de l'Estrade. The departmental leisure base is used mainly for sailing and windsurfing by schools, school trips, sports associations and holiday camps, and canoeing, mountain biking, paddleboarding and pedal boating are also practised.

The lake lies on the Ganguise river in the Aude, near Avignonet-Lauragais, with shores laid out for hiking and picnic areas around the water. A nautical base serves sailing and windsurfing schools, associations and holiday camps; canoeing, mountain biking, paddleboarding and pedal boats are also possible. The dam is an earth dike barring the whole Ganguise valley.

The dam was first proposed in 1951 but only built in 1979, as an earth dike closing the whole Ganguise valley. In 2007 the dike was raised three metres, doubling the lake's area from 278 to 500 hectares and pushing the water as far as Cumiès.