High water mark

As insurers work with Canadians to reduce flood damage, the shores of Ontario’s Great Lakes are higher than they have been in 30 years, putting properties at risk.

“We are well above where we typically are for water elevations in Lake St. Clair and the Detroit River,” reports Andrew Dowie, executive initiatives coordinator for the City of Windsor. As a result, officials are concerned about potential flood risk in the Windsor area. The same is true further north along the Canadian shore of Lake Huron. On the Huron shore, a boardwalk in the Town of Goderich was badly damaged this past October after a storm caused 10-foot waves, the Signal-Star newspaper reported at the time. “The concern right now is our water treatment plant,” Larry McCabe, chief administrative officer for the Town of Goderich, told Canadian Underwriter a month after the incident. At the time, there was no actual damage to the plant but town politicians approved a project to help protect the plant. The project includes placing armour stone of various sizes along the waterfront to stop waves from damaging the treatment plant.

There is risk to private property as well. On a 50-kilometre stretch of shore north of Goderich, more than 700 properties have at least one structure at risk from a sudden collapse of bluffs, according to the London Free Press, quoting the Maitland Valley Conservation Authority.
As of press time, the surface of Lake Huron was the highest it has been since 1986. “There are anticipated rises of levels in 2020 that we are hearing about,” McCabe reports.

Insurers contacted for this story declined to comment about claims arising from higher-than-normal Great Lakes levels. But it seems intuitively obvious that higher water levels and faster-running watercourses elevate flood risk in certain areas of the province, potentially leading to higher claims costs.

As of Nov. 29, 2019, the Great Lakes were 18 to 33 inches above their average monthly level, the U.S. Army Corps of Engineers reported at the time.

Lakes Michigan and Huron were four feet above the “chart datum,” which Fisheries and Oceans Canada defines as a low water level agreed upon by Canada and the United States for the purpose of making charts for ships and boats. Lake Erie was three feet and 10 inches above chart datum, while Lake Ontario was two feet and nine inches above chart datum on Nov. 29. “Lake Ontario is the only Great Lake that has a chance of getting near or returning to its long-term average by spring 2020,” the International Lake Ontario-St. Lawrence River Board said Nov 22.

The spring timing is key. Catastrophe Indices and Quantification Inc. (CatIQ), which keeps track of the Canadian property and casualty insurance industry’s losses, reports that the occurrence of weather-related catastrophes has shifted from summer to spring.
And it’s not simply a simple matter of lowering the water levels via lock systems. The International Lake Ontario-St. Lawrence River Board is one of several organizations falling under the International Joint Commission, which regulates bodies of water straddling the border with the United States. Among other responsibilities, it regulates the flow of water through the Moses-Saunders Power Dam and nearby locks.

The Moses-Saunders dam crosses the St. Lawrence River near Cornwall, Ont. and Massena, N.Y., between Kingston and Montreal. Almost all water from the Great Lakes eventually passes by the dam before flowing further downstream, eventually draining into the Atlantic Ocean. The dam is controlled by Ontario Power Generation on the Canadian side and the New York Power Authority on the American side.
The faster the water flows through the Moses-Saunders dam, the quicker Lake Ontario can drop. But that in turn increases water velocity in narrow watercourses, which could lead to public safety issues. For this reason, the authorities must exercise caution when they change water levels.