The massive sinkhole that opened up on Rideau Street last year was likely caused by sandy soil and not a watermain, the City of Ottawa says.
The City released a final report on what likely caused the massive sinkhole to open up at the corner of Rideau Street at Sussex Drive on June 8th 2016. The engineers’ report, which was completed in December, was released Wednesday after repeated accesses to information requests were sent to the city.
According to the document, city engineers say the sinkhole likely started with unstable, “saturated soil” that led to the ground giving way forcing a south side watermain to burst.
"The loss of ground likely occurred very rapidly because the ground had previously been disturbed and loosened," the report says.
The report goes on to say that “water flowing from this rupture then caused erosion of the loosened, sandy soils below the watermain and the flow of a vast amount of soil into the west running tunnel, thereby creating the large sinkhole.”
As the sinkhole expanded to the north side of the road, another watermain gave way.
The report also says finding a root cause was complicated by the more than 3,000 cubic meters of concrete that was poured into the hole within 24 hours.
There have been 32 claims for compensation made by business and property owners affected by the sinkhole. A claim for $1.4 million has also been submitted by the city.
More to come.
