Polar View River Ice Monitoring Service Improves Flood Prediction in Canada

Polar View’s river ice monitoring services, when used in conjunction with sea ice models, help local authorities in Canada make better predictions about when flooding events might occur on the island of Newfoundland.

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Since 2003, the Water Resources Management Division of the Newfoundland and Labrador Department of Environment and Conservation has been using Polar View’s river ice monitoring services to help them make better predictions about when floods might occur.

The monitoring services is of particular use to the residents of Badger, a small town located in the centre of the island of Newfoundland at the confluence of Newfoundland’s largest river, the Exploits River, and two smaller brooks. Badger has a long record of frequent flooding dating back to 1916, the first time a flood was witnessed. Flooding occurs when ice builds up in the Exploits River – or other rivers feeding it – and blocks the normal flow of the water, causing the river to overflow its banks.

Predicting the floods

The Water Resources Management Division of the Newfoundland and Labrador Department of Environment and Conservation has provided a flood monitoring service to the island of Newfoundland since 1977. In order to predict how much ice might form in the Exploits River on a given night, the Hydrologic Modelling Section of the division developed an ice progression model (IPM) for a large section of the river.

Every year between December and March, surfaces of rivers in Newfoundland becomes covered in ice, which means this is the most important time of the year to monitor river ice. Since surface ice usually starts to appear downstream from Badger and gradually makes its way upstream throughout the winter until the spring thaw begins in March, the ice progression model divides the Exploits River into 32 separate segments to facilitate modelling river ice cover. The model predicts whether river ice will form in a given section based on temperature and other weather conditions in each segment.

However, even models are not able to tell you everything. No one was able to predict the sudden collapse of the ice on the Exploits River on the morning of February 15, 2003. The sudden collapse created an ice dam, which blocked the normal flow of the river just downstream from Badger. This led to a record 2.3-metre rise in water levels in the area around Badger, which completely inundated the town, resulting in large-scale damage.

The Ice Progression Model is not able to predict the condition of the river ice or the location of the ice front along the Exploits River. It can only tell whether or not there should be ice at a given location based on certain meteorological conditions in the area. Only having much better information on the condition of the river ice prior to the flood could have given a clearer picture of what was about to happen.

In the aftermath of the February 2003 flood, Dr. Amir Ali Khan, who manages the Hydrologic Modelling Section, looked into ways of improving the capabilities of the flood prediction service. He considered making use of satellite imagery to get a regularly updated overview of ice conditions on the Exploits River. There are several places along the river where ground observations can be made. However it is impossible to observe from the ground all 50 kilometres of the river being monitored.

Earth observation makes the difference

Earth observation technology turned out to be the solution. Mr. Thomas Puestow, who manages Polar View services provided by member organisation C-CORE, contacted Dr. Khan and offered to provide him and his team data and images from earth observation satellites. C-CORE was able to create from scratch an entirely new service that uses data taken from satellites equipped with synthetic aperture radar (SAR), which can take images even through cloud cover and bad weather. The new service was at the time the first of its kind in the world (prior to this SAR data had not before been used to look at river ice specifically).

Dr. Khan is very happy with the improvements to the flood prediction service he and his team provide at the Water Resources Division thanks to the river ice monitoring services C-CORE has been providing.

“The satellite data have been a great help in improving the accuracy of our predictions, since we can now monitor things like where the ice front is and factor this into our models,” said Dr. Khan.

The Water Resources Management Division has been using the river ice monitoring service C-CORE provides every year since the winter of 2003-04. During the first season the Polar View service was in operation, it was able to monitor the location of the ice front along the Exploits River. In the following years, the service began looking at the stability of the river ice (using various change detection algorithms along the river). A third and new ice classification service able to classify the kind of ice it can detect (whether the ice is loose, jammed or packed) was added in 2009.

The information and images the river ice monitoring service provide on the Exploits River are readily available to local residents on the website of the Water Resources Management Division. This allows residents, business owners and authorities in Badger and elsewhere to keep abreast of any important developments.

“The river ice monitoring service has always been very, very popular,” Dr. Khan mentioned. “The user community seems to be growing as more and more people get to know about it.”

A number of other water management authorities in Canada and even some in Russia have adopted similar river ice monitoring services provided by Polar View in recent years.

“The most useful aspect comes when we have severe weather conditions and we can’t send out observation flights. Satellite images come through regardless of weather.”