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Municipalities need billions to bolster Lower Mainland dikes

Jean Sorensen
Municipalities need billions to bolster Lower Mainland dikes

This is part one of a two-part series exploring issues facing municipalities when it comes to critical dike upgrades in the Lower Mainland and beyond. In this article, stakeholders describe the importance of preparing for the next big flood or earthquake.

Dike authorities surveyed in a 2015 Lower Mainland assessment report, which found only four per cent of dikes were high enough to contain a major flood, have made “negligible” progress in making necessary upgrades, said a B.C. government spokesperson.

“Some municipalities (authorities) may have undertaken small-scale, structural upgrades, but the extent to which these upgrades have bettered the regional state of the dikes is negligible,” said Vivian Thomas, media relations officer for the Ministry of Lands, Forests, Natural Resource Operations and Rural Development, in an email.

“The cost of the upgrades to the existing dike network is estimated to be in the billions of dollars.”
The 2015 assessment was used in Phase 1 of the Lower Mainland Flood Management Strategy with Phase 2 underway through to 2018.

“Phase 2 is focused on developing regional priorities for dike upgrades and other mitigating measures and developing a secure, sustainable funding model for implementation,” said Thomas.

Phase 3 is implementing a strategy that evolves, which is not expected to occur until after 2018. But one action that has evolved as B.C. faces repeated river floods, global warming causing rising seas and the threat of a major seismic event, has been B.C.’s remapping of floodplains and new building restrictions.

Thomas said the ministry has amended its Flood Hazard Area Land Use Management Guidelines to incorporate sea level rise into the determination of building setbacks and flood construction levels in coastal areas. The effective date for the guidelines is Jan. 1, 2018. It sets the global sea level rise of half a metre by 2050, a metre by 2100 and two metres by 2200.

B.C. is also facing more river flooding and the 2012 report, Simulating the Effects of Sea Level Rise and Climate Change on Fraser River Flood Scenarios, warns large floods that used to occur once every 200 to 500 years will be more likely to take place once every 50 years.

The 2015 assessment report mainly utilizes information from the various dike authorities and lacks field work. Thomas said B.C. is still currently trying to pull together more information on the region’s diking system. The ministry estimates 100 dike authorities in the region, although some dikes are orphans with no authority.

Over the years, Lower Mainland dikes were built to differing standards with earthquake concerns not an issue. B.C. has commissioned the Fraser Basin Council to work on Phase 2 and consider seismic best practices and guidelines for engineers and geosciences when upgrading dikes, but those recommendations are several years away.

Fixing the Lower Mainland’s dikes is riddled with logistical and financial challenges and a subsequent 2016 report warns that municipalities should have back-up emergency plans in place until solutions can be found to mend the dikes.
The barrage of B.C. reports and studies is only telling government what municipalities already know. While the threat is there, the cupboard is bare, said Chilliwack Mayor Sharon Gaetz.

“There is absolutely no way that a city can provide diking to its citizens with the dollars generated from the local tax base,” said Gaetz, who has issued evacuation notices to residents in the past. “The Fraser came very close in 2007,” she said, as residents packed Chilliwack’s Coliseum seeking relief.

Chilliwack, like other cities, has been assuming the role of a once independent dike authority. The three levels of government all paid a one-third share of upgrading dikes, according to Gaetz. Currently, Chilliwack needs $30 million to upgrade a critical section of downtown dike.

“If you look at the community, there are about 40,000 in the downtown area and that area is not properly protected by dikes at this moment,” she said, adding that earthquake modelling also suggests the dikes would breach. The impact would not only be on housing but a major rail line, hospital, several schools and aboriginal lands that were never diked.

“It isn’t like we have not been shouting from the top of the roof,” she said. “The federal and provincial governments both are well aware of the issues facing Chilliwack.”

Currently, Chilliwack has upgraded half of its 40 kilometres of dikes. Gaetz isn’t alone.

Find out how other cities are being impacted by dike concerns and upgrades in part two of this series.

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