Environmentalists had called for years for the construction of new dams in Czechia’s Brdy mountains to reverse damage caused by the communist-era Czech military.

The project was seven years in the works and held up by issues around land ownership when it was discovered the beavers had beaten authorities to the punch.

The beaver dams were built precisely on the bypass gully created by soldiers in the former Brdy military base decades ago, Radio Prague International reports.

The head of the Brdy protected landscape area administration said the beavers had saved them around 30 million Czech crowns – around €1.2 million or £990,000.

“They built the dams without any project documentation and for free,” he added.

A senior official in Czechia’s nature and landscape protection agency said: “Beavers always know best. The places where they build dams are always chosen just right – better than when we design it on paper.”