Wednesday, December 07, 2011

Builders revise plans as higher sea levels predicted

By: Frances Bula From:  The Globe and Mail

City engineers and developers are beginning to revise building plans to allow for new projections for higher sea-level rises on the B.C. coast.

Park benches which in July would usually provide a serene place to sit and watch the placid Fraser River flow by Paddle Wheel Park, adjacent to Farrell Street, are now surrounded by the rising waters of the Fraser River which tears by in full flood. - Park benches which in July would usually provide a serene place to sit and watch the placid Fraser River flow by Paddle Wheel Park, adjacent to Farrell Street, are now surrounded by the rising waters of the Fraser River which tears by in full flood. | Dave Milne/ The Globe and Mail

Park benches which in July would usually provide a serene place to sit and watch the placid Fraser River flow by Paddle Wheel Park, adjacent to Farrell Street, are now surrounded by the rising waters of the Fraser River which tears by in full flood. Dave Milne/ The Globe and Mail

In Vancouver, the company building a significant development along the Fraser River in the southeast part of the city is planning to raise its land about two-thirds of a metre. Dikes along the river in Richmond are also being planned to go higher.

And city engineers are considering options like flood-control gates, “sacrificial” first floors, and more as they plan for a 200-year future where it's being conservatively estimated the ocean may rise at least two metres.

“We have to think about raising the land up in several areas,” said Vancouver's chief city engineer, Peter Judd, who has commissioned an extensive study to calculate exactly what new requirements the city should put in place. “You need to be able to build a floor level here so you can be confident it's not going to flooded at some point.”

Mr. Judd said he is hoping to set new guidelines by mid-2012 that will help developers and the city plan buildings, roads, sewer lines and more to be workable as the ocean rises.

Buildings are typically estimated to have a 50- to 100-year life, so buildings already up around the Vancouver shoreline will meet new guidelines as they are torn down and redeveloped.

Other coastal communities around B.C. are going through the same exercise as Vancouver, as they slowly come to grips with a report from the provincial government six months ago that projected a significantly higher sea-level rise than it had set out in earlier years.

Those cities are also working through their own assessments to figure out what the province's very general and bare-bones projection – a one-metre rise by 2100, a two-metre rise by 2200 – means for them with their different terrain near the ocean.

Those that have low, flat land near the shore or along rivers near the ocean, which can be affected by incoming tides, have the most planning to do.

For Vancouver, affected areas mean all of the land around False Creek and the False Creek Flats, a formerly marshy area filled in 100 years ago. New plans will specifically affect development on either side of the just-completed Olympic Village, and a new Concord Pacific project planned on the opposite shore.

As well, it affects all the land along the Fraser River, with immediate impacts for a massive new 10,000-resident development in the southeast corner of the city that has been years in the planning by ParkLane Homes.

ParkLane has already commissioned its own study to get exact details about the impacts, said the company's development vice-president, Norm Shearing.

“This has pushed everyone forward,” he said. “The modelling is hugely complex ... but we know we need to raise our site's habitable floor level up by 0.6 metres.”

Mr. Judd said the city lands near the Olympic Village will likely be raised well over a metre. Concord Pacific is waiting to hear the outcome of the city's study before making any decisions.

Mr. Judd said that the city's more detailed projections could go two ways. The water-level rise will likely be lower than the province's projections at shorelines that extend inland.

But he noted that the provincial projection is conservative one, significantly lower than the highest predictions.

He wouldn't be surprised if that has to be revised upward again within a few years, given the historical pattern.

“It was a pretty constant increase starting in the 1970s. But it's accelerated since the mid-1990s.”

In Richmond, the province's new guidelines came as less of a jolt because that municipality, which is essentially a delta of the Fraser River, does constant updating of its projections on sea-level rise.

“This is one more step for us in a continuum of flood-protecting planning,” said city engineer John Irving. “We already require builders to build higher in the West Cambie area, getting completely lifted up by a metre and a half.”

Around the new River Green complex being built on the river near the Olympic Oval, the city is asking the dikes to be built up to as high as 4.7 metres.

Like Vancouver, Richmond has a $200,000 study in the works to flesh out the province's study.

“Their guidelines are premature. To establish meaningful guidelines, we need to do much more detailed work.”

Mr. Irving said the toughest aspect of the new guidelines is for the smaller communities and diking associations that don't have a lot of money to do their own studies.

They need additional help from the province, as well as financial support to contribute to building up dikes.

© 2011 The Globe and Mail Inc. All Rights Reserved.

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