Vancouver prepares for the flood
Vancouver looks at sea gate, dikes and raising roadways to prepare for increased flooding risk in a warmer future
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From a sea gate at the mouth of False Creek to raising the seawall to retreating altogether from low-lying coastal areas, the City of Vancouver is exploring a range of options to anticipate future sea level rise.
“We haven’t nailed down whether it’s going to be a dike or adaptation or a combination of those two things, but the fact that sea level will rise, we know it’s absolutely going to happen,” said Doug Smith, director of sustainability for the City of Vancouver.
“It’s just a question of whether it will be 50 years or 70 years or 150 years.”
While many of the options presented at a Nov. 2 council meeting would be years in the future, the city is preparing to go ahead with one project in 2017: raising a portion of NW Marine Drive by adding three inches of asphalt, near the Sasamat intersection near Jericho Park.
That project will replace the sandbagging the city does every year to protect Jericho Park from potential King Tide flooding, which the city fears could reach into residential areas.
The province has forecasted a sea level rise of one metre by 2100 as warmer temperatures cause sea and land ice to melt. But oceanographer John Englander recently estimated sea level could rise by 20 to 30 cm by 2050, said Tamsin Mills, senior sustainability specialist at the City of Vancouver.
The Lower Mainland Flood Management Strategy has estimated that direct losses from river and coastal flooding could exceed $30 billion by 2100. In 2013, flooding in Calgary and Toronto cost insurers $3.2 billion.
City staff have identified five areas that are particularly vulnerable to flooding, which would likely happen with a combination of high winter tides, a storm and sea level rise.
Fraser River industrial lands, Jericho Park, Kitsilano Park, False Creek and Waterfront Road near the Seabus terminal are all at higher risk.
A sea gate (similar to the gate in place in the Thames River in England) is one option for False Creek, although it would cost up to $800 million and be the highest-maintenance choice.
Dikes and raising the seawall are other options for most of the locations identified, Mills said, with shoreline dikes estimated to cost $90 million to $160 depending on the location. Flood gates that can be installed on the doors of businesses, vents that can reduce the water pressure during a flood and putting stricter building regulations in place are other things being considered.
Retreating from an area gradually over time is another option, involving buying up properties over time. That strategy would eventually result in loss of land, Mills noted.