A new pond will be created in Prague’s Letná park to help combat drought

A tunnel built by Rudolf II will supply water to a new pond that was part of Letná park's original design

Raymond Johnston

Written by Raymond Johnston
Published on 07.05.2020 12:20 (updated on 07.05.2020)

Prague City Hall will start building a new pond in Letná park this year. It will be located near the Hanavský pavilon and will be supplied with water from the Vltava by a pump. The project will in part rely on a 16th century irrigation tunnel built by Emperor Rudolf II.

A building permit has not yet been issued, but the city has a zoning decision. The costs have not yet been calculated, but are estimated to exceed 10 million CZK.

“If everything goes according to plan, construction will start in September. The Letna orchards are relatively dry and there is a problem with water; we do not even have lawn irrigation. The slope is completely dry and the plain is not the best. When we looked at history, [landscape architect František Josef] Thomayer counted on a water surface there, but no one ever got around to building it,” Dan Frantík, the head of the municipal department for green care, said, according to press reports.

Thomayer was active in planning Prague’s parks in the late 19th century. He also worked on planning Karlova náměstí, Vrchlického sady and Čelakovského sady, among other spaces.

The new lake’s area will be about half a hectare. Water will be pumped into it through one of the three working shafts of Emperor Rudolf’s tunnel from the 16th century. “There will be a pump below, which will pump water and then it will go down the pipes by gravity into the water surface,” Frantík said. The city does not count it being fed from the surface, as lawns in the vicinity absorb water.

Hanavský pavilon
Hanavský pavilon in Letná park / via Raymond Johnston

The construction will be quite difficult. “It has to be sealed relatively well so that the water, which we pump up in a relatively difficult way, does not flow back again. The biggest costs will be for sealing,” Frantík said.

The pond in Letná will also be built to combat drought. In April this year, the capital struggled with the driest period in the last six years. The average monthly flows at all monitored sites reached approximately one-quarter of the usual amount for this month.

The current drought situation in the Czech Republic is the worst in 500 years, according to the Czech Environment Ministry.

In addition to lakes, Prague wants to build underground water reservoirs inside the city, repair ponds and expand the number of trees on streets in the fight against drought.

The 16th century tunnel that will help supply the water was built to create ponds in Stromovka park, and is still in use. It was briefly open to the public at the turn of the 21st century, but closed after the floods of 2003.

rudolf tunnel
House under Letná at the entry to Emperor Rudolf II’s tunnel; / via Raymond Johnston

Parts of the infrastructure such as a house to control the entry, ventilation shafts, and an entry portal in Stromovka with Emperor Rudolf II’s seal can still be seen. The lakes in Stromovka were renovated recently as part of an ongoing project to revitalize that park.

Letná park began as a military camp in middle ages, and was later a vineyard. It did not become a park until the 19th century. Recent renovations in Letná include the restoration of a landing platform for a former cable car system that went up to the top of the hill. Work has also started but stalled on renovating a historical carousel.