Toronto swimmers using real-time sensors to get data on changing lake conditions

Open water swimmers have been deploying sensors in popular swimming spots in Toronto and Lake Ontario to get information on changing water conditions. Nick Westoll has more on why some swimmers say the data is needed.

With the hotter and more humid weather we’ve seen in the Greater Toronto Area, it might be tempting to head down to Lake Ontario for a swim.

However, an open water swimmer and competition organizer along with a few other enthusiasts have turned to sensors to gather real-time information on changing water conditions. They’re carrying out the effort to help prevent people from getting into trouble.

“I’ve long had an itch to scratch, which is why can’t we get real-time water temperature?” Steve Hulford said at Humber Bay Park West on Saturday.

“Water temperature is a difficult thing to get. You might come and check the temperature at the shore and it could be two or three degrees cooler, you know, 20 yards out.”

He said it’s information that’s vital year-round for swimming recreationally or planning competitions.

“Do I need to wear a wetsuit today or do I not? And this is why it is a danger to a lot of people who are not aware of what’s going on. They may go on the lake, it could be four or five, six degrees,” Hulford said.

Sudden cold water changes can even happen on a hot summer’s day, especially after a storm, he added.

“We have this effect that takes place where the water will turn over, the water column will literally flip and the bottom water will come to the top, and the top will disperse and the water temperature can go from 20 or 23 C to 4 C in a matter of 12 hours,” Hulford said.

“If you’re not properly dressed for it … you could certainly get in trouble.”


RELATED: Ontario app helps users find beaches with the safest water


Should someone exposed to unexpected colder water, it could impact their body.

“Immediately when you get into the water, like there’ll be a shock, and that’s your body’s response to the cold water,” he said.

“All the blood rushes to your heart, your organs, your brain and away from your legs and arms.”

During the pandemic, Hulford and a few others began setting out buoys using technology that has become cheaper and more accessible. Using your phone or your desktop computer and visiting Open Water Data, you can get lots of data quickly. It also keeps historical readings too.

The devices are at Ontario Place, Cherry Beach, Woodbine and Kew-Balmy beaches. In mid-June, the technology came to Humber Bay. Readings are pumped out online every half hour.

“The water temperature sensors down here and this is in the water,” Hulford said, holding up one of the devices during an interview with CityNews.

“It does its readings, it goes back to sleep. The battery in here can last three to four years and we just put a chain in a cinderblock on it and it just sits at the water level.”

The plastic device is roughly the size of a large juice container, but Hulford emphasized it can withstand harsh conditions. He said they want to expand the technology to Toronto Islands, Scarborough and Mississauga while building awareness.

“It potentially could save lives, sure. You know its purpose … is to provide a combination of water temperature data, e.coli levels …combine it all and track it by beaches.”

Regardless of the water conditions in Toronto, make sure you take precautions such as dressing appropriately and telling people where you’re going.

“Stay in shallow water, know your skill level, know what the water temperature is, stay in the swimming boundaries, and have fun and take care,” Hulford said.

Links to sensor data in Toronto

Humber Bay
Ontario Place
Cherry Beach
Woodbine Beach
Kew-Balmy Beach

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