Powisle station: photo - Warsaw Metro
“Building a tunnel of this type is not simple,” Hanna Gronkiewicz-Waltz, Thursday morning.
Last week, water flooded into the tunnel at the planned Powiśle station, which will become part of an east-to-west metro line.
Police closed off roads and a major bridge across the River Vistula, which the tunnel must go under, as a precaution.
“Fortunately, nobody was hurt,” Mayor Gronkiewisz-Waltz said.
An investigation into where the water came from has proved inconclusive.
Builders have had to submerge the site still further to even out the water pressure.
Because of the uncertain situation regarding the leak, road authorities closed have neighbouring tunnel on one of the Polish capital's busiest boulevards.
Traffic has been redirected, causing considerable transport problems in the already gridlocked city.
Since the leak happened, the construction consortium has been trying to locate the source and re-route of the problematic water. Simultaneously, appraisals of the situation are being carried out by the local government investor.
Yesterday, constructors announced that drilling work would continue on the right bank of the river to minimalise delay. However, Warsaw Metro authorities have said that no binding decision has yet been taken and that any conclusions are not expected until the middle of next week when the results of the surveys are known.
The two giant drilling machines have already dug almost 1050 metres and 670 metres of tunnel respectively.
According to the plans, the tunnel under the Vistula was to be 600 metres long and lie 7 to 8 metres below the river bed. Apart from the submerged site at Powiśle, to be one of the deepest-situated stations, work continues on all remaining sites of the second line of the Warsaw metro away from the affected area. (ek/pg)