Huge increase in sewage bypasses this summer
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The thunderstorms that rolled over Niagara this summer have been a worst-case scenario for Niagara’s sewer infrastructure.
As a result, Niagara Region’s associate director of waste water operations Jason Oatley said 1.167-billion litres of partially-treated sewage went into Niagara’s watercourse in May, June and July.
That’s an 8,000 per cent increase over the 14.4 million litres of sewage bypassed during the same three months, a year earlier.
Most of the sewage bypasses occurred in May, although an additional 73 million litres of sewage was dumped in the months that followed.
“It’s been an unusual year. We had a lot of small, intense storms,” Oatley said.
“Very localized areas would have brief events of 15 or 20 minutes.”
Although the storms that hit Niagara this summer were shortlived and isolated, he said they often dumped a great deal of water on relatively small areas. And when it comes to water and sewer infrastructure, he said that’s a worstcase scenario.
Oatley said Niagara had 43 rainy days this summer, compared to 18 from May to the end of July in 2016.
And the sudden influx of stormwater spilling into sanitary sewers during storms exceeded the capacity of treatment plants, forcing the region to dump partially-treated sewage into watercourses.
The increase in rainy days this summer “meant that the ground around the sewers and pumping stations stayed wet and didn’t have much time to dry out before the next rain event occurred,” Oatley said. “This would increase the amount of infiltration and inflow into the wastewater system during rain events. Couple with the number of storms and intensity of rainfall this year, it produced this abnormal amount of bypasses at our plants.”
Oatley said isolated storms normally cover half the region at a time. But this year, he said there could be torrential rainfall in one community, and “it might not rain at all just a few kilometres away.”
He recalled one such storm in Fort Erie earlier this week.
“It was just an unbelievable torrential rainfall, and yet it was nothing in other places,” Oatley said. “It’s just picking and choosing where it’s going to rain, and it’s very unusual.”
In addition to the sewage bypasses, he said Niagara’s plants also treated nearly 20-billion litres of sewage — about 700-million litres more than the in the same time period a year earlier.
The same problems with sewage overflows have been plaguing communities on the U.S. side of the border, too, after a sewage discharge into the Niagara River in late July, attributed to human error on the U.S. side, has increased public awareness about the issue.
But sewage bypasses have continued to occur in the U.S. as a result of the weather.
“I think they have a lot of attention being paid to those overflows,” Oatley said. “Those (sewage bypasses) would be normal for extreme events.”
The Niagara Region publicly reports sewage overflows on its website niagararegion.ca. ABenner@postmedia.com Twtter: @abenner1