May has already seen a month’s worth of rain

WATERLOO REGION — Parts of Waterloo Region have already received as much rainfall in May as would fall in an entire month.

But the very wet start to May has not broken any rainfall records, and hasn’t resulted in any severe flooding, thanks to timely management of water flows through the network of dams and reservoirs in the Grand River watershed.

The region endured steady rain from Thursday until Saturday evening, filling area waterways to just short of flood levels.

Anywhere from 45 to 60 millimetres of rain fell during that period, said Rob Kuhn, a severe weather meteorologist with Environment Canada. Waterloo Region actually got off fairly lightly. Areas north and south of us got more rain, and many parts of Canada, including western Quebec and the Maritimes, are coping with floods.

“It’s been a wet week,” Kuhn said, noting that the average rainfall for May for the area is 81 mm. “Since the beginning of May we basically had close to a month’s worth of rainfall.”

All that rain causes river flows to swell. In a typical summer, about 15 cubic metres of water flows through the river in downtown Cambridge each second, said Cam Linwood, a spokesperson for the Grand River Conservation Authority. But by late Saturday, peak flows through the Galt area of Cambridge had reached 370 cubic metres a second. Lowerlying areas of Galt typically flood when flows hit 400, Linwood said.

The lack of flooding “is a testament to what was happening upstream,” he said.

The authority uses the watershed’s seven dams and reservoirs to regulate the flow and reduce the likelihood of flooding. Water was released from reservoirs earlier in the week before the rains hit so that reservoirs would be able to store more of the rain.

Some flood-prone areas were affected. High water closed at least three roads over the weekend: the Black Bridge Road and Rogers Road, as well as Riverside Park in

Cambridge, and the Three Bridges Road where it crosses the Conestogo River upstream of St. Jacobs. Kitchener closed Rockway and Doon golf courses as well as sports fields.

Water levels and flows in the river system are still quite high and will remain so for about a week, Linwood warned. “And the water is still very cold,” he said. “We want to make sure people stay well back from the river.”

Residents awoke Sunday to the first glimpse of sunshine in many days, a portent of the drier, cooler weather forecast for most of this week.

There is no rain in the forecast until Wednesday night, when there is just a 40 per cent chance of showers. But the temperatures are expected to stay cooler than normal for the next several days.

Normal highs at this time of year are 18C, with a normal low of 6C, but the highest the mercury is expected to climb is 14C on Friday, with lows as chilly as -2C forecast for Sunday night. Environment Canada issued a frost advisory for Sunday night, with widespread frost expected over most of the region into Monday morning.