How Digital Twins Safeguard Cities Against Natural Disasters
Experts say the recent floods in Canada are a reminder to other cities about using digital twins to protect residents from natural disasters
Digital twins have a role to play in helping cities better plan ahead and minimize damage as emergencies related to natural disasters become more frequent, according to experts.
This comes as three days of torrential rainfall battered parts of Atlantic Canada earlier this week. Residents in Cape Breton had to contend with 10 to 15 cm of rainfall, while the same storm dumped 20 cm of precipitation on residents in Victoria County, N.S., prompting officials to declare a state of emergency.
The situation wasn’t much better in Port aux Basques, a town in the southwestern region of Newfoundland. The town is expecting 30 cm of rainfall by the time the storm passes on Thursday. It usually sees an average of 160 mm spread out over all of November.
The rain has already washed out roads, flooding the main part of the Trans-Canada Highway and a smaller secondary highway along the southern coast, effectively cutting off the town of 4,000 from the rest of the island, according to the Canadian Press.
Out west, cleanup efforts continue in British Columbia, which saw historic flooding mid-November and a summer where record-breaking temperatures created a deadly heat dome and the third-worst season for forest fires in the province.
What Happened In B.C.?
A natural phenomenon known as an atmospheric river swept over the province, dumping over 10 cm of rain in 24 B.C. communities from Nov. 14 to Nov. 15, according to Environment Canada.
The town of Hope, B.C., smashed previous records and endured over 25 cm of rain over the weekend. To put things in perspective, the town’s average rainfall in all of November is 34.4 cm.
Atmospheric rivers are when bands of moist air travel from the tropics to the poles. In this case, the one passing over B.C. was carrying lots of moisture, and when it passed over the cooler mountain regions, turning that excess moisture into rain. They typically pass over a coastal region in 20 hours. The one in B.C. took close to 72 hours, according to the Globe and Mail.
What Were The Repercussions?
Flooding and landslides triggered by the sudden and heavy rainfall turned deadly, killing at least four people and leaving one person missing. It also wreaked havoc for communities located on low-level land and for anyone transporting or receiving goods.
The B.C. government entered a two-week state of emergency on Nov. 17 to help manage the distribution of food, supplies and fuel due to damaged roads making transporting goods near impossible. It says 17,775 people have been displaced by evacuations related to flooding. Over 9,000 more properties are either on evacuation order or evacuation alert.
For farmers, many had to abandon their livestock in order to get to safety and dramatic footage emerged of some trying to guide cattle on jet skis and canoes to higher ground. It’s the latest blow to dairy and livestock farmers as the brutal heatwave in the summer killed off many crops and animals. Farmers fortunate to have animals after the flood now face logistical nightmares about restoring power, keeping animals fed and healthy and transporting their goods to distributors.
At the Port of Vancouver, Canada’s largest seaport, shipping delays began piling up due to washed-out railroads, impacting deliveries from Canadian Pacific Railway Ltd. and Canadian National Railway Co. The delays meant nearly 1,000 rail carts carrying grain sat idle, Bloomberg reported.
Where Do Digital Twins Fit In?
While observers have described the weather conditions behind the flooding as something that only happens once in a century, other cities should take heed now, if you ask Ali Asgary.
“Other cities should realize that we are entering a phase of climate change when the past data may not sufficiently describe the frequency and severity of natural hazards events,” said the associate professor of Disaster & Emergency Management at York University in Toronto.
“It is imperative that cities update their risk assessment, treatment and communication models and approaches, and cost-benefit analysis to consider the new realities. More investments in risk mitigation and adaptation, as well as emergency preparedness, are needed if we aim to reduce the cascading and catastrophic impacts,” he added.
A 2019 white paper by Bentley Systems, a U.S.-based software company, specifically highlighted digital twins as a tool that cities should adopt to reduce flooding damage.
“Predicting floods in a city is challenging because “compound” flooding can result from a combination of origins, such as a river, rainfall, storm surges, sea level rise, and soil sealing. It is only possible to face these types of flood events with a holistic approach with software capable of integrating the different flood origins, such as flood modeling and simulation solutions. The results that these solutions generated can then serve as a simulation input to a city’s digital twin.”
It’s worth noting that B.C.’s flooding could be classified as a pluvial or rain-related flood but remains unique in the sense that it was hit with a double whammy of cause factors: intense rain as well as run-off, due to the summer’s forest fires that created a waxy top layer preventing the soil from absorbing some of the rainfall, according to experts quoted by the CBC.
For Asgary, there are additional benefits for cities to adopt digital twins: education as well as hazard and risk analysis.
“Using 3D models and digital twins, it’s possible to better measure the effectiveness of various hazard mitigation and adaptation measures. Such information is also more appealing and effective for communicating the risk and risk mitigation to the general public,” he said.
“The real world is a 3D world. 3D modelling and visualization is the best way to [view] reality.”
Flood evacuees seeking more information can head here for the latest details from the B.C. government