Lake Vogrsko, Reservoir in Slovenia

Lake Vogrsko is an artificial reservoir in Ajdovščina Municipality created by damming the Vogršček stream. It holds approximately 8.5 million cubic meters of water and serves both agricultural irrigation in the nearby Vipava valley and recreational purposes.

The reservoir was created by damming the Vogršček stream between 1985 and 1989. The dam was built by the company Soča from Nova Gorica; at 31.4 m high, it was then the tallest dam in the country, containing 234,000 cubic metres of earth and rock. After a wet patch appeared below the dam in 2007, repeated repairs followed until major rehabilitation began in 2020, including a 144 m tunnel.

The name comes from the Vogršček stream, dammed between 1985 and 1989 by the company Soča from Nova Gorica. The stored water irrigates the Šempas, Prvač and Dornberk fields of the Vipava valley, while the two northern arms are kept for sport fishing of carp, pike and tench and for recreation.

A 3–4 hour walking path circles the lake, manageable for anyone able to walk that long. The H4 expressway runs along the northern embankment, and the small northern bay bounded by it has gently sloping, overgrown banks, while the rest of the shoreline is bare. The northern arms are the better choice for fishing and recreation.

The northern arms of the lake hold 39 recorded dragonfly species, 53% of Slovenia's fauna of these insects. The northeast arm is the only place in the Vipava valley where the protected and critically endangered small red damselfly (Ceriagrion tenellum) has been recorded. Water there is 6 m deep and reaches 28 °C at the surface in summer.