Former mine in North Bohemia filled to create country’s largest pit lake
A new water reservoir created by filling a former brown coal mine has officially opened in North Bohemia, near the town of Most. With a surface of over 300 hectares, Lake Most is the Czech Republic’s largest pit lake to date. The project, which cost some CZK 2.5 billion, took nearly 12 years to complete.
The newly opened Lake Most is located at the site of a former historic town of the same name, which was demolished in the 1970s and 1980s to make way for a brown coal mine. When the operation of the Ležáky mine ceased in 1999, efforts began to revitalize the landscape, ravaged by giant coal diggers.
Miroslav Seidl is from the fuel processing plant in Ústí nad Labem, which is in charge of reclaiming the former lignite mines.
“In October 2008, we started filling the pit with water. It took altogether six years, with a two-year break, during which the banks were strengthened.
“Because we didn’t have sufficient water supply, the water was taken from the River Ohře, from a source near the Nechranice water reservoir.
“Today, the lake has a surface of 309 hectares and there are over 70 million cubic metres of water.”
Before filling the pit with water, the lake bed had to be sealed with clay to ensure it wouldn’t leak, while bulwarks were built to prevent the waves from breaking the banks, built on the spoil heaps.
Today, there are over a two dozen bird species nesting in the area and various fish species living in the crystal clear water. Miroslav Seidl says it is being constantly monitored to make sure it is safe for swimming.
“The lake is up to 70 metres deep, which creates a self-cleaning effect. There is also a controlled fish stock, which prevents the overpopulation of carp-like species.
“To keep the composition of species stable, fishing won’t be permitted in the area. And since there is no inflow or outflow, there is also a ban on using motorboats.”
At the moment, the lake features several beaches and a children’s playground. In the future, when the banks become more stable, there is a plan for more recreational facilities and a marina.
A smaller lake, called Milada, has already been created at the site of the former Chabařovie mine near the town of Ústí nad Labem.
It opened in 2015 and has since become a popular destination for local people, offering opportunities for swimming, water sports, in-line skating and cycling.
The two lakes are part of a larger effort to reshape the North Bohemian landscape destroyed by decades of mining. Part of the plan is to create a network of lakes stretching from the city of Chomutov to Ústí nad Labem, which would be interconnected by canals.
One of the mines that could be turned into a water reservoir in the future is the ČSA mine, currently still in operation, which would be 20 times larger than Lake Most.