LRT tunnel flooded after sinkhole to take 'at least' a week to pump out

It will take "at least a week" to pump out the water that flooded into the light rail tunnel last week after Rideau Street collapsed, according to the city official in charge of implementing Ottawa's LRT system.

At its deepest point, the water stands at 2.5 metres, according toSteve Cripps, the directorof the city's rail implementation office. A roadheaderin that exact areais also likely to be partly submerged in water, Cripps said.

Last Wednesday, the Rideau Streetwatermainabove the LRT tunnelburst. On Friday, Rideau Transit Group confirmed there was some flooding in about 300 metres of the tunnel.

RTG is estimating that it'll be at least a week of pumping water out before it's completely drained...- Steve Cripps, director of rail implementation office

Crews spent the weekend pumping out the water. Before they began, the waterstretched across more than 300 metres of the tunnel.

There's now only about 200 metres of the tunnel affected by water a sectionbetween Elgin Street and the sinkhole in front of the Rideau Centre.

Water must be pumped more than 1 km

"Since the tunnel slopes down, the farther in you go, it will get deeper," said Cripps. "And its deepest point will be where the tunnelexcavationended. The water would be 2.5 metres at that point. And that would represent about half the tunnel."

Cripps said RTG can't say yet whether the tunnel was completely flooded, but "we're confident the tunnel was not compromised because of the water."

Still, pumping the water out of the tunnel presents "a couple of challenges," he said.

"First of all, it's a fair distance to pump it back to the west portal. The west portal is close toLeBretonFlats. So that's actually a distance of over a kilometre. So that alone takes some time."

And when the water arrives, it has to be treated inRTG'swater treatment plant near LeBretonbefore being poured into the sanitary sewers, adding more time to the procedure.

"So right now, RTG is estimating that it'll be at least a week of pumping water out before it's completely drained and crews are able to get right to the face of the excavation," said Cripps.

Rideau Street expected to be open in 2weeks

The cause of the sinkhole is still not known. And while Cripps said hedoesn't believe theLRT will be delayed by this setback, the completion of the tunnel digging only 50 metres remain will likely be later than expected.

Even if the roadheader is damaged from the flooding, Crippssaid it wouldn't cause any delays as RTG has three of the machines and the tunneling is almost finished.

Efforts to pump water out of the tunnel will not interfere with other work to repair water mains, sewers, gas and telephone connections, said Cripps.

The city is working to restore water services to the CIBC and Holtz Spa this week. A number of other business were reconnected Monday, although they are operating under boil-water advisories. The city wasn't sure how many businesses remain without telephone services.

He expects Rideau Street will be open in a couple of weeks.

"As it stands today,we don't see any challenges in meeting that timeline."