Water Log

As I paddled into Kingston last September, after a six-day traverse along the north shore of Lake Ontario, I spotted a pair of neoprene-covered heads bobbing in the harbour. Val Hamilton and Mary Ann Higgs, septuagenarian best friends, were testing their brand new wetsuits. They wanted to continue swimming as the weather turned cold. Hamilton was in the midst of radiation therapy for cancer. Immersing herself in the water every day, she explained, could help reduce swelling. A few years earlier, she added conspiratorially, detecting my interest in all things lacustrine, she had spent a month swimming across more than twenty of the region’s lakes. Each one smelled different.

How well can anybody know a lake? My stand‑up paddleboarding voyage down the length of Lake Ontario, from the Golden Horseshoe to Kingston — the second-to-last leg of a wider waterborne circuit, starting in and returning to Ottawa via Montreal, New York City, and Toronto — revealed a thin slice...