A team of experts hired by Quebec's Transport Ministry says building a tunnel between Quebec City and Lévis is possible, but the project would cost around $4 billion.
Bruno Massicotte, a civil engineer and professor at Montreal's École Polytechnique, presented the results of the one-year feasibility study Tuesday, which cost the government $100,000.
Massicotte says building the 7.8-kilometre tunnel would take around 13 years. Maintenance over the next century would cost an estimated $2.3 billion, for a total cost of $6.3 billion.
"Technically, it's feasible. There are other tunnels of this size that have been built under the same conditions in other places," said Massicotte.
Sandy soil would drive up costs
The sandy soil of the northern bank of the St. Lawrence River where the tunnel would be located means construction crews would have to inject cement into the sand to solidify the tunnel's structure, and that would drive up the cost.
"The sand is full of water, so in case of a major earthquake it would liquefy and turn into water for a few seconds. That's why the tunnel has to be bigger, tougher," said Massicotte.
'In case of a major earthquake, [the sand] would liquefy ... That's why the tunnel has to be bigger, tougher.' - Bruno Massicotte, civil engineer and professor at the École Polytechnique
This technology is fairly new, and Massicotte says building the tunnel wouldn't have been possible a decade ago.
He says for a long time, people questioned if it would be safe to build over Logan's Line, a geological fault beneath the St.Lawrence.
"The fault hasn't been active for more than 250 million years. There can be earthquakes for other reasons, but the Logan's Line is not an obstacle," said Massicotte.
Quebec's next move
The study was handed over to the Quebec government last April, said Massicotte.
"Every morning I am reminded that we need to improve traffic fluidity on the region's two bridges, and we will continue to," said Minister of Transport Laurent Lessard in a statement.
Dominique Vien, the minister responsible for the Chaudières-Appalaches region, said she has asked the Ministry of Transport to look into different scenarios.
Meanwhile, a local non-profit organization which promotes urban planning and public transportation says building a third link to connect both shores would be the wrong way to go.
"We need to focus on the Rapid Bus Transit that is currently in the works," said Étienne Grandmont, the executive director of Accès transports viables.
"That is the best solution to improve traffic and diminish urban sprawl."