Prague Signs Off CZK 359 Million to Watch the Ground Under the Eastern City Ring

Prague's city council has approved the contractors who will watch the ground while the first holes are dug for the eastern half of the City Ring Road. The contract covers geotechnical monitoring and a condition survey of buildings along two sections, Pelc/Tyrolka – U Kříže and Balabenka – Rybníčky, and is worth just under 359 million crowns including VAT. It went to SG Geotechnika and Pudis, Zdopravy.cz reported on 20 October.

It is the first money committed to physical work on the ring's completion, and it is not yet for the road. It is for what comes before the road: exploratory adits driven along the lines of three of the future tunnels — Bílá skála, Jarov and Malešice — to find out what the rock is actually like.

What the money buys

The contract is split in two. Monitoring on the Pelc/Tyrolka – U Kříže section comes to roughly 126.3 million crowns, and on Balabenka – Rybníčky to roughly 232.6 million. The report does not say which of the two firms took which part.

Three things are being paid for. Geotechnical monitoring tracks how the rock behaves as the adits are driven, and feeds the next stage of design. Groundwater is monitored alongside it. And the buildings around the works are surveyed and their condition documented in detail, before the adits are started and again after they are finished. The city presents that last part as a guarantee to the people living above: if something cracks, there is a record of what it looked like beforehand.

The monitoring is not a one-off. It runs for as long as the adits are being driven and continues until the main tunnels are started; the hydrogeological part explicitly carries on after the adits are complete. Given the durations set out in September — four years for Bílá skála, about 42 months for Jarov, 30 for Malešice — that is a contract measured in years.

The bigger tender is still to come

The monitoring is the smaller of two contracts. The survey itself, which includes driving the adits, is estimated at 2.47 billion crowns including VAT, and Zdopravy.cz reports that the city plans to advertise it this year. Driving the adits should then start at the turn of the second and third quarters of next year.

The timing has moved a little. When the designers presented the schedule in September, Zdopravy.cz reported that the survey tender was due to be called within a month, that the monitoring winner had already been chosen and awaited councillors' approval, and that contracts were to be signed in November. The approval has now come. The survey tender, a month and a half later, is still described as planned for this year.

Where the scheme stands

The eastern section is the last missing part of the inner ring, and its completion has been in preparation for decades. After the redesigns of recent years it is 10.5 kilometres long, 8.5 of them in tunnel, with a design speed of 70 km/h. The latest date for starting the first part of construction is 2029.

The paperwork is moving on a parallel track. The environmental decision was updated in August, with the changes to the scheme and new conditions for building it. The documentation for the permit was finished in September and is now being consulted on; the application to DESÚ is due in December, and a permit — not yet final — is expected next year.

Read together, the two tracks show what kind of project this is. Before the city can apply for permission to build the road, it is already paying to drill into the hill under Bílá skála, because four fifths of the route is tunnel and nobody can price a tunnel without knowing the ground. The 359 million crowns now approved buy the record that makes that drilling defensible to the people who live on top of it.