Government officials in the Brdy region reportedly received approval for CZK 30 million but were unable to acquire the appropriate approvals to build the dam in the Klabava River's protected area.

Due to sediment and acidic water spilling over from nearby ponds, the river is home to a population of critically endangered crayfish.

The project was first drafted in 2018 but was halted by lengthy delays in negotiations over the land that the military uses as training grounds.

Then, officials discovered that a colony of eight beavers had built a dam in the area, saving the government millions.

"The Military Forest Management and the Vltava River Basin were negotiating with each other to set up the project and address issues regarding ownership of land. The beavers beat them to it, saving us CZK 30 million," said Bohumil Fišer, the head of the Brdy Protected Landscape Area Administration.

"They built the dams without any project documentation and for free."

The officials believe it would have taken the beavers just over a day to build the dam.

Jaroslav Obermajor, head of the Central Bohemian office of the Czech Nature and Landscape Protection Agency, told Radio Prague: "Beavers always know best."

"The places where they build dams are always chosen just right – better than when we design it on paper."

Ecologists say the dams the beavers have built should last a long time and create good conditions for the crayfish, frogs and other wildlife that thrive in the wetlands.