2016 Ottawa sinkhole
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A massive sinkhole, spanning four-lanes of traffic, unexpectedly appeared on June 8, 2016 on Rideau Street in downtown Ottawa just blocks from Parliament Hill. It was adjoined an excavation for the underground Rideau station on the Ottawa light rail Confederation Line, which was under construction. It halted the construction of the long-awaited underground Light Rail Transit. The sinkhole or the associated water main break caused a gas leak, forced the evacuation of several buildings in the heart of Canada’s capital, such as Rideau Centre shopping mall and a hotel where hundreds were attending a conference, swallowed a minivan, but spared a crowded bus that passed just minutes before the sinkhole opened. Time Magazine reported that the incident happened weeks before Barack Obama and other world leaders were scheduled to arrive in the Canadian capital for a summit .
The broken water-main flooded the sinkhole and 300 metres of the LRT tunnel. The 130-tonne roadheader opening that tunnel was submerged. A similar sinkhole had occurred elsewhere along the construction route in February 2014, but the 2016 event occurred as the tunneling effort was nearing completion with only 50 metres remaining.
The area of the collapse had long been identified as unstable, with "loose fill, silty clay and 'glacial till'" overlying a valley in the limestone below. Jim Watson, the city's mayor, said that the city had launched an investigation into the collapse.
On 10 June the Ottawa Sun reported that a boil-water advisory was lifted for the food court at the Rideau Centre, but remains in effect for others. Ottawa Health advises food businesses in the Rideau Centre to run the cold water for five minutes to clear the pipes before using the water.
On 13 June concrete was poured into the sinkhole which by then had swallowed three lanes of pavement. At that time, it was reported, Rideau Street remained closed, some of the buildings were still without water and others were under a precautionary advisory to boil water. Rideau was being used as a bus and taxi transitway while crews beneath were boring a tunnel for a new light rail transit line in the area. The cause of the sinkhole has yet to be determined. Three hundred truckloads of cement were used to stabilize the hole, which had been 40x28Template:Nbspmetres, to a depth of 5.5Template:Nbspmetres. Metro Ottawa reported that City manager Steve Kanellakos confirmed that "significant progress" has been made on repairing the sinkhole on Rideau Street near Sussex Drive.
On 14 June the boil-water advisory was lifted for some Rideau Street addresses, as the city continued to deal with the consequences of the sinkhole. Ottawa Public Health issued the water notice for six addresses along Rideau Street, but clear test results were received, so the advisory was lifted for those locations, permitting them to reopen. The boil-water advisory remains in effect for other businesses on Rideau Street.
On 17 June, Watson announced that the transitway was on track to re-open to bus and automobile traffic the week after. At the time water continued to be pumped from the city's light rail tunnel, where it had accumulated to a depth of up to 2.5 metres.
By 20 June, crews were still continuing to backfill and completing repairs to buried cables, while the city was forecasting a further week of road closure.
Investigation by the City of Ottawa
On 18 June 2016 the CBC reported that an investigation into the cause of the sinkhole would also look into why it took city crews two hours to stop water pouring from a watermain into the LRT tunnel.
- Austen, Ian (9 June 2016). "Sinkhole Opens Under Busy Street in Downtown Ottawa". The New York Times. ISSN 0362-4331. http://www.nytimes.com/2016/06/09/world/americas/ottawa-sinkhole-rideau-street.html.
- Pearson, Matthew (10 June 2016). "Packed bus passed over sinkhole site 'minutes' before road collapsed" (in en-US). http://ottawacitizen.com/news/local-news/ottawa-sinkhole-day-2-what-to-know-about-closures-causes-precautions.
- "'I can't believe the size of it': Ottawa sinkhole collapses road, forces evacuations". CBC News. 8 June 2016. http://www.cbc.ca/news/canada/ottawa/sinkhole-rideau-street-downtown-ottawa-1.3621949.
- Pfeffer, Amanda; Foote, Andrew (10 June 2016). "Sinkhole Day 5: Businesses remain closed while crews continue pumping out tunnel". CBC News. http://www.cbc.ca/news/canada/ottawa/rideau-sinkhole-tunnel-lrt-watermain-1.3632723.
- Chianello, Joanne (18 June 2016). "City to look into why water shutdown after sinkhole occurred took 2 hours". http://www.cbc.ca/news/canada/ottawa/rideau-sinkhole-tunnel-flooding-watermain-1.3640297.
- Steele, Alistair (9 June 2016). "Engineers flagged Ottawa sinkhole site as 'bad area' of unstable bedrock valley". CBC News. http://www.cbc.ca/news/canada/ottawa/ottawa-sinkhole-rock-valley-1.3623008.
- Kassam, Ashifa (8 June 2016). "Sinkhole spanning four-lane road swallows van in Ottawa". The Guardian. http://www.theguardian.com/world/2016/jun/08/sinkhole-ottawa-swallows-van.
- "Ottawa Sinkhole, Day 3: Boil water notice mostly over". 10 June 2016. http://www.ottawasun.com/2016/06/10/ottawa-sinkhole-day-3-boil-water-notice-mostly-over?utm_source=facebook&utm_medium=recommend-button&utm_campaign=Ottawa%20Sinkhole,%20Day%203:%20Boil%20water%20notice%20mostly%20over.
- "Concrete poured into Ottawa sinkhole that swallowed 3 lanes of pavement". 13 June 2016. http://www.680news.com/2016/06/13/concrete-poured-into-ottawa-sinkhole-that-swallowed-3-lanes-of-pavement/.
- "Infrastructure failure at Rideau and Sussex". City of Ottawa. http://ottawa.ca/en/infrastructure-failure-rideau-and-sussex. Retrieved 20 June 2016.
- Pearson, Matthew (14 June 2016). "Ottawa Sinkhole: Boil-water advisory now lifted for most Rideau Street addresses" (in en-US). http://ottawacitizen.com/news/local-news/ottawa-sinkhole-boil-water-advisory-now-lifted-for-most-rideau-street-addresses.
- Foote, Andrew (17 June 2016). "Post-sinkhole Rideau Street expected to open late next week, says Jim Watson". http://www.cbc.ca/news/canada/ottawa/rideau-street-sinkhole-repair-open-1.3640407.
- "City crews to resume LRT tunnel excavation this week". Postmedia News. Ottawa Sun. 20 June 2016. http://www.ottawasun.com/2016/06/20/city-crews-to-resume-lrt-tunnel-excavation-this-week.