An aging water main beneath Stanley Park that's been a steady source of leaks and flooding will soon be replaced.

On Wednesday, Metro Vancouver held its first round of public consultations over a new drinking water supply tunnel that will run underneath Stanley Park, connecting downtown Vancouver to an existing water main in the Burrard Inlet.

The current water main, which carries potable water, was built in the 1930s and is nearing the end of its lifespan, according to Goran Oljaca, director of engineering for Metro Vancouver Water Services.

"We've been having minor leaks over the last 17 years," said Oljaca, adding that age and corrosion led to flooding near Vancouver's Lost Lagoon in 2016.

The pipes will also receive significant seismic upgrades, he said.

Goran Oljaca

Goran Oljaca stands in front of Vancouver's Lost Lagoon. The the proposed water supply tunnel will run beneath it. (Jon Hernandez/CBC)

Digging tunnels

The new 1.4 kilometre pipe system will cost upwards of $100 million. The plan is to dig a tunnel up to 50 metres beneath Stanley Park in order to limit the impact on green space, nearby businesses and residences.

However, Oljaca says the team will have to dig a centre shaft inside the park.

Stanley park tunnel

A cross section of the Stanley Park water supply tunnel project highlights three points that will be excavated to build the tunnel. (Metro Vancouver)

"All the excavation would happen from the centre of the park. We would build the tunnel to the two end points," he said, adding that the group is obligated to restore any reduced greenspace.

He says the new tunnel will also increase the overall volume of potable water flowing into Vancouver, anticipating future population growth.

Construction of the project is expected to begin in 2020, following other water main replacements near the Port Mann, Annacis Island, and Second Narrows.

Stanley Park

The new water tunnel would run from Chilco and Alberni, through Stanley Park, towards the Burrard Inlet. (Metro Vancouver)