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Laskosky is hoping a University of Alberta research project on the storm water ponds will indicate if residents can someday safely skate again. Results are expected later this year.

In the meantime, many people still make rinks on the ponds. They can be fined $500 under the drainage bylaw, which prohibits going on storm-water ponds except where allowed by the city manager.

The recent controversy is linked to a $100 ticket handed out just before New Year’s Eve. Resident Brian Tomlinson checked online — where the city had forgotten to update its information — and saw skating on storm-water ponds was allowed. He started to clear and flood a small rink on Poplar Lake, a fenced, environmentally sensitive wetland, and was stopped by park rangers. He was fined under the Parkland bylaw.

Laskosky said she thinks the holes are being caused by complicated flow patterns between the 160 interconnected ponds. She didn’t see the same issues when there were only 25 ponds two decades ago.

Mark Loewen, the civil engineering professor leading the research project, said preliminary results indicate road salt is also causing some of the issues. His students studied four ponds for two winters, taking photos every 15 minutes and monitoring ice thickness both manually and with ground-penetrating radar.

Loewen said ice tends to be thinner near the inlets. Each pond typically has three or four of the inlets submerged about 20 metres off shore, where local residents wouldn’t see or necessarily expect them. Every time Edmonton gets a warm spell, salty run-off from surrounding roads and parks enters the ponds through these submerged pipes and weakens the ice above. The low freezing temperature of salt water accentuates that process.