Frank Van Ninaton, assistant manager of the environmental services for the city of Chilivak, stands on the banks of the Fraser River, meters from the dike that protects the city from floods. DARRYL DYCK / The Globe and Mail
When rivers overflow their banks, the resulting damage is not simply the result of the vagaries of nature. It is also determined by how many homes, farms, roads and hospitals people have built along the flood.
A new analysis by The Globe and Mail found this out of 150 Canadian communities with a population of over 10,000, more than 30 have at least one-tenth of their buildings in floodplains. This analysis was facilitated by new nationwide flood maps published by the University of Western Ontario.
Chilliwack, BC, stands out: More than 18,000 buildings in this metropolitan area are located in the floodplains of the Fraser and Veder rivers. This is almost half of all buildings in the city – no other community we explored is approaching. High River, Alta, where thousands of homes were damaged by floods in 2013, is emerging as another community with extensive floodplain development.
Again and again, construction in floodplains is exposed as an expensive habit. It can doom cities to painful cycles of devastation and recovery, with high financial and psychological costs for affected residents.
Globe and Mail analysis of flood patterns from
The University of Western Ontario shows this
more than 30 communities in canada have
at least one tenth of their buildings in river floodplains. Chilliwack, BC had an unusually high exposure. The Community relies on safety net dikes.
15 CITIES WITH THE LARGEST PROPORTION
OF BUILDINGS IN 100-YEAR-OLD FLOATING RUBBER
Buildings 100 years old
floodplain
Border of the metropolitan area for census
MURAT YUXELIR / GLOSS AND POST, SOURCE: TILEZEN; OPENSTREETMAP CONTROLS; STATISTICS CANADA; MICROSOFT; UNIVERSITY OF WESTERN ONTARIO
Globe and Mail analysis of flood patterns from
The University of Western Ontario shows that more than 30 communities in Canada have at least one-tenth of
their buildings in the river floodplains. Chiliwak, British Columbia
there was an unusually high exposure. The Community relies on safety net dikes.
15 CITIES WITH THE LARGEST SHARE OF BUILDINGS
IN A 100-YEAR-OLD FLOWING LOWLAND
Buildings in a 100-year floodplain
Border of the metropolitan area for census
MURAT YUXELIR / GLOSS AND POST, SOURCE: TILEZEN; OPENSTREETMAP CONTROLS; STATISTICS CANADA; MICROSOFT; UNIVERSITY OF WESTERN ONTARIO
The Globe and Mail’s analysis of flood patterns from the University of Western Ontario shows that more than 30 communities in Canada have at least one-tenth of their buildings in floodplains. Chilliwack, BC had an unusually high exposure. The Community relies on safety net dikes.
15 CITIES WITH THE HIGHEST PROPORTION OF BUILDINGS IN 100 YEARS OF FLOOD
Border of the metropolitan area for census
Buildings in a 100-year floodplain
MURAT YUXELIR / GLOSS AND POST, SOURCE: TILEZEN; OPENSTREETMAP CONTROLS; STATISTICS CANADA; MICROSOFT; UNIVERSITY OF WESTERN ONTARIO
This was demonstrated dramatically just west of Chiliwak, in the Sumas prairie, a famous floodplain that flooded last November after a dike broke. The federal government and British Columbia expect to bear the cost of recovering $ 3.9 billion from the November floods, almost all of which will eventually be paid for by federal taxpayers. This is the largest disaster recovery fee in Canada’s history – and in addition to what homeowners, farmers, businesses and municipalities have to pay out of pocket.
Additional public funds are sometimes spent on massive flood protection works to protect vulnerable neighborhoods after the fact. The federal government is also considering a program to facilitate the relocation of homes and businesses from high-risk areas, which may require even more public spending.
And yet, despite official policies at many levels of government that seek to limit the development of floodplains, some cities continue to allow it. Meanwhile, as the Earth’s climate warms, the footprints of many floodplains are expected to expand.
How to protect or abandon such places can become an increasingly pressing dilemma for all levels of government – as well as the question of who has to pay when past permits lead to tragedy.
Bumper gaps
Maps of the city of Chiliwak in the floods largely confirm those of the University of Western Ontario. In fact, the 2007 municipal map shows a significantly larger floodplain, mainly because the Chilivak maps show more severe flooding than the Western ones. But there is a significant difference: the municipal map classifies most of the scattered floodplain as “protected.”
It is a reference to the 50-kilometer-long dikes surrounding the city, protecting tens of thousands of residents, businesses, water mains, railways, the Trans-Canadian highway and a hospital.
The official Chilliwack Community Plan only discourages development in a handful of areas considered “unprotected”. This is part of a pattern observed in cities across the country: Dikes are attracting more development, thus increasing exposure to floodplains. DARRYL DYCK / The Globe and Mail
Burial began in the 1860s, when settlers flooded the area. The impetus for greater construction and upgrading of dikes was provided by major floods from the Fraser River in 1894 and 1948 and in 1975 from the Veder River.
These dikes provided confidence, which was crucial to Chilliwack’s growth. The development originated on the northern side of the current Trans-Canadian Highway, but spread south to cover the former communities of Sardi and Veder and up the surrounding hills.
Recently, Chiliwak is one of the fastest growing cities in Canada, with a 12 percent increase in the 2021 census compared to 2016. The total number now exceeds 113,000, and municipal officials expect growth to continue in the coming decades. .
Daryl Moniz, a real estate broker and president of the Chilliwack and District Real Estate Board, said affordability is pushing home buyers to Chilliwack. “They want a detached house with a white fence, the dream of their family, as opposed to housing, which is a reality for many first-time buyers in the Vancouver area,” he said.
However, finding a place for this growth is a challenge. Chilliwack is surrounded by provincially protected agricultural lands and neighboring first nations. The demand for many thousands of new homes has led to an intensification of existing neighborhoods at the bottom of the valley, as well as some development in the nearby hills.
The official Chilliwack Community Plan only discourages development in a handful of areas considered “unprotected”. This is part of a pattern observed in cities across the country: Dikes are attracting more development, thus increasing exposure to floodplains.
DARIL DICK / The Globe and the Mail
Above are new two-story houses under construction in Chilliwack this month. Below, a home in Chiilwack’s Yarrow neighborhood was flooded in November 2021. JESSE WINTER / Reuters
In Chilliwack, Mr Moniz said the floodplain was a “minor to inappropriate” consideration in real estate transactions. “It’s just a way of life, more or less, in the western part of BC.”
The problem is that flood defenses can fail and their maintenance is often neglected.
The history of Chilliwack proves this. As severe floods broke out in 1948, locals east of the city belatedly realized that their dikes needed to be built. According to a modern story, they “put into operation their own trucks, turned a 10-acre pasture into gravel and formed the core of an army of 3,500 people.”
These last-minute efforts spared Chilliwack and its environs from total flooding. However, the dikes failed and several neighborhoods were flooded, most notably in the Mennonite community of Greendale on the Sumas Prairie, west of Chilivak, which became a 34-foot-deep lake.
“After the Greendale break,” the account notes, “Chliwack has taken stock of its own defenses and found they don’t need it.”
And not for the last time. An estimate from 2015, published by the British Columbia Department of Forestry, Land and Natural Resources, notes that many dikes around Chilliwack are “currently too low” or have other shortcomings.
People run and walk on the dike on the north arm of the Fraser River, in Vancouver, Friday, April 22, 2022. Daryl Dyke / The Globe and MailDARIL DICK / The Globe and the Mail
Over the last decade, work has continued to upgrade the dikes, starting in eastern Chiliwak and moving downstream on the Fraser River. Officials told The Globe that the work could take another decade or more to complete, and depends in part on federal and provincial funding.
Officials are fully aware of what is at stake. A 2009 study by engineering firm BGC Engineering estimated the potential damage from a major flood at about $ 1 billion. “The consequences of a breach in the city’s flood protection system would be far-reaching,” the 2016 municipal report said.
“We do not start with a blank page and we have to work with the city as it has been developed for years …
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