Nova Scotia

How a new tool can predict coastal flooding in Nova Scotia down to the metre

A web tool developed by researchers at the Nova Scotia Community College aims to help emergency planners decide precisely where roads should be closed and to develop specific evacuation plans before flooding hits.

Project aims to give emergency officials precise information so they can plan up to 10 days ahead of time

NSCC's Tim Webster is using LIDAR to get a highly accurate picture of Nova Scotia's coastline and tidal region. (Applied Geomatics Research Group, Nova Scotia Community College)

The developers of a made-in-Nova Scotia web tool say it can predict the flow of coastal flooding right down the metre, precise information that will give provincial emergency officials days to prepare for incoming seawater from storm surges.

As concerns increase about flooding along the province's shoreline, and billions have already been spent dealing with similar problems on the U.S. Eastern Seaboard, a group at the Nova Scotia Community College has researched a way to better prevent damage and save lives.

A big part of the solution is to more accurately predict flood pathways using an online mapping tool, something Tim Webster in NSCC's Applied Geomatics Research Group in the Annapolis Valley has been working on for more than a year and a half.

"We're in our final stage of tweaking and wrapping it up now," he said.

A model of what a three-metre rise in sea level would look like for downtown Halifax. (Applied Geomatics Research Group, Nova Scotia Community College)

10 days of advanced warning 

Advanced notice would give emergency planners up to 10 days to decide precisely where roads should be closed and to develop specific evacuation plans.

The issue right now, Webster said, is Nova Scotia's Emergency Management Office receives imprecise information from Environment Canada, which makes planning more difficult. 

"Typically a very broad-scale map with big circles on it that say, 'Predicting storm surge along the eastern coast. High surf could cause flooding and a storm surge may cause flooding.' That's it," said Webster.

'Unprecedented detail'

Webster's team uses a light detection and ranging (LIDAR) sensor on board an aircraft to get "unprecedented detail" of the coastline and tidal region beyond the coastline for high-risk coastal flooding areas.

There's LIDAR data for the Halifax Regional Municipality, the Minas Basin, Lunenburg, Yarmouth, Amherst, Pugwash, Antigonish, the Sydney area, communities in New Brunswick along the Northumberland Strait and the coastal Charlottetown area on P.E.I.

That information is then combined with tidal data and storm surge predictions from Environment Canada plugged into Webster's software, giving an extremely accurate prediction of the path of floodwaters. 

The tool predicts what parts of the coast may be inundated, including which roads and emergency depot locations — such as fire, ambulance, and hospitals — may be affected. 

A screen shot of the map looking at Nova Scotia's Minas Basin. (Applied Geomatics Research Group, Nova Scotia Community College)

The system will launch March 31 as a tool for the Emergency Management Office and other government officials.

Sea level rise predictions due to climate change

The tool also has implications for predicting sea level rise as a result of climate change, said Webster, even decades down the road.

"Town planners could look at, 'Well, we're building some infrastructure, where are we planning to build it?' Does that flood now? What about in 50 years time, would it flood? What about in 100 years time?" said Webster.

The National Oceanographic and Atmospheric Administration released a report earlier this year predicting oceans could rise by as much as 2½ metres by the year 2100.

Currently, the software is only being used to predict the impact of coastal flooding. Webster said the tool could also be adapted to complicated river patterns in an effort to predict floods such as those in Cape Breton last Thanksgiving, Truro in 2012 and Alberta in 2013.

"This type of system could be built for inland flooding, as well, but it's typically a more complicated problem and one needs to have more information to do such a prediction system," he said. "But it is possible if we had the information."

The project is funded by the Canadian Safety and Security Program, a federally funded program led by Defence Research and Development Canada's Centre for Security Science, in partnership with Public Safety Canada. It is locally managed by the Nova Scotia Department of Natural Resources.

The owner of this vehicle in Sydney arrived to find her truck under water during the Thanksgiving 2016 flood. (Brett Ruskin/CBC)