Low Lake Ontario water level turns Cootes Paradise marsh into mudflats

Have you visited the Cootes Paradise mudflats recently?

It's not your imagination: spring water levels in the normally paddle-friendly marsh, Hamilton Harbour and the rest of Lake Ontario are much lower than in recent years.

Specifically, Lake Ontario is sitting at 74.48 metres above sea level. That's about two-thirds of a metre lower than this time last year and the lowest March level since 2015, said Frank Seglenieks, the secretary for the international board that controls outflow from the lake into the St. Lawrence River.

That's still nowhere near" the historic lows of 1936 when spring levels dropped below 74 metres, he noted, and only 21 centimetres lower than the 100-year average. But the receding waters may look jarring because we've become used to flood conditions.

Lake Ontario busted through two record highs between 2017 and 2019, drowning trails, beaches and basements along the way before cresting at 75.92 metres. That flood risk was enough to convince regulators to open the taps at the Mose-Saunders dam last winter to allow months of very high outflow" from the lake into the St. Lawrence River, said Seglenieks.

That safety-valve decision, combined with abnormally dry" conditions in the Great Lakes basin over six months, resulted in the low levels you see today. Whether that's good or bad depends on your point of view.

On the upside, the risk of shoreline flooding and wet basements is down substantially - a relief to low-lying beach strip homeowners and taxpayers staring down tens of millions of dollars in shoreline protection due to past damage.

In muddy Cootes Paradise, the Royal Botanical Gardens is eyeing redoubled efforts to replant native wetland plants - something recent floods have made difficult, said natural lands head Tys Theijsmeijer. We will see a lot of plant recovery this year," he predicted.

But if you're a regular Cootes kayaker or canoeist in the city's most popular paddling spot, your options have shrunk considerably" this spring, said Theijsmeijer.

Still, it's always possible lake levels will bounce back to or above average if spring is wetter than normal, cautioned Seglenieks. It's the time of year when we can see a lot of variability," he said.

Matthew Van Dongen is a Hamilton-based reporter covering transportation for The Spectator. Reach him via email: mvandongen@thespec.com