A rainy day was Monday for some homeowners

Along Charles River, yards flood after ‘rare’ summer breach

WELLESLEY, Mass. — At the end of River Road, the river met the road. Not that it was supposed to. But after an hour or two of torrential rain Monday morning, the Charles River, already swollen from tropical rainfall last Friday, breached its banks, flooding nearby yards and basements.

One homeowner said he had seen the Charles flood during late winter and early spring when snow melted, but never in July. Perhaps he should get used to it.

“The current pattern that we have here is part of a trend of generally getting wetter in the Northeast,” said Dr. Upmanu Lall, an engineering professor at Columbia University, who studies climate.

Lall said part of it may be due to global warming. But the Atlantic and Pacific oceans are also having an influence on the jet stream. Unfortunately, most of the water that falls over the Northeast has nowhere to go, since bedrock and granite provide aquifers of a fractured nature, Lall said.

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“And these fractures may be several centimeters or inches to several meters wide,” he said. “So sort of like a cave structure.”

Water easily flows into these caves but also easily flows out. Lall said along the coasts, aquifers are sandy and water seeps in more slowly and stays in the ground longer.

That lack of natural, long-term storage may be influencing decisions on mandatory water-use restrictions, which stay in place in many Massachusetts communities during the hottest months of the year. At present, 122 cities and towns are under mandatory orders and three are under voluntary restrictions.

The Massachusetts Department of Environmental Protection told Boston 25 News that, technically, water suppliers could ease up on use restrictions if the flow rate of a nearby river exceeds an established minimum for seven days. At present, the Ipswich, Concord, Taunton and Charles rivers, among others, are well above their minimums.

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But that does not mean restrictions will come off anytime soon. The DEP said suppliers feel consistency creates compliance. So some have chosen to go with the simple message of tightening water use from May to September. Lall said, additionally, water suppliers tend to plan for the worst-case scenario.

And finally, weather is unpredictable, especially if climate change is a factor. July’s heavy rains could just as easily be followed by drought conditions in August.