When disaster struck in a small Quebec community recently, the response was quick, and the decision to repair the dike an easy one to make. Ensuring that the community wouldn't face more problems called for very specific equipment use.
Two Gilbert Grizzly MultiGrip vibratory pile drivers were used in Sainte-Marthe-sur-le-Lac as part of the work to repair, raise and waterproof the dike.
Nearly five kilometres of sheet piling were driven during this work, which had to be completed as quickly as possible.
Urgent work needed
On April 27, 2019, a state of emergency was declared in Saint-Marthe-sur-le-Lac when a natural dike broke under the force of water, forcing the evacuation of 2,500 properties, or about 6,500 residents. These floods caused panic in this small municipality located in the Deux-Montagnes RCM in Quebec, which overnight evacuated nearly one-third of its population.
This disaster was a total surprise for the entire population, as they had trusted the dike for so many years. Within minutes after the breakage, several residents were able to see the water rising very fast on their property and were forced into an urgent evacuation.
Quickly, echoes of this disaster were felt across the country as several teams from Sûreté du Québec, the Canadian army and neighbouring municipalities were deployed to provide assistance to the victims.
Following this highly publicized disaster, the Quebec government authorized the municipality to carry out the necessary work to secure its land base in anticipation of the 2020 spring flooding season as well as to protect against the anticipated effects of climate change over the next 100 years.
More specifically, the work involved reinforcing, raising and waterproofing the dike using sheet piling and riprap placed on the embankments. Aware of the importance of completing the work as soon as possible in order to ensure the safety of the residents and allow them to finally regain a certain peace of mind, the contractor in charge, ETPO Geodex, chose the Gilbert Grizzly MultiGrip for installation of sheet piling.
In total, nearly 2000 AZ 14-770 type sheet piles from 6 to 8 metres long were driven in order to carry out work according to internationally recognized technical principles and respecting the highest engineering standards.
The sheet piling, erected using vibratory pile drivers, will provide resistance that will allow the municipality to easily face future spring floods.
Accessibility and deadline challenge
Due to the proximity of residences, it was necessary to work with equipment that ensured easy access to the site while minimizing inconveniences caused to residents.
The Gilbert Grizzly MultiGrip, which can be installed on a 22- to 45-ton excavator, proved to be the ideal equipment for the work.
Thanks to its great versatility, it was possible to quickly handle a large number of sheet piles while reducing ground vibration.
For Sainte-Marthe-sur-le-Lac's citizens, this disaster will undeniably leave its aftereffects for a long time. A large number of houses had to be completely destroyed after the floods and will take months or even years to be rebuilt.
The local population has faced low morale and many health issues due to concern over potential future flooding issues. Many of the residents have expressed that they are considering leaving the community entirely.
These human factors were drivers of the push to repair the dike as quickly as possible.
Thanks to the new high-quality design, which allows maximum protection against potential hazards from the water, the residents of Sainte-Marthe-sur-le-Lac are unlikely to face another disastrous flood in the future - allowing them to instead focus on healing of their people and the community itself.