This spring's heavy rain in the Lake Ontario region had quite an impact on homeowners, but it also affected the water offshore. The rainfall overwhelmed sewage systems in cities around the lake, and pushed millions of gallons of raw sewage into the water.
Mike Garland is director of environmental services for Rochester and the rest of Monroe County, N.Y., which means he's in charge of showing off the county's wastewater treatment center.
“It’s a dirty job, but someone’s gotta do it,” he says, as he walks through the center.
Garland says this facility treats about 100 million gallons of sewage per day. Most days, everything works as it should, and no untreated sewage winds up in Lake Ontario.
But when a big rain floods the sewage pipes, the center can't always keep up.
“The system wasn’t designed to handle every storm event," Garland says. "We know we can have very intense storm events."
One such event occurred on May 1. That day, five U.S. and Canadian cities dumped nearly 90 million gallons of untreated sewage into Lake Ontario.
Emergency overflows in Rochester and Oswego, N.Y., as well as Hamilton, Toronto, and Kingston, Ontario, were all caused by record amounts of rainfall.
Such a huge amount of sewage can be harmful, says Gary Pettibone, professor of biology at Buffalo State College.
Sewage carries bacteria and organisms that can harm people when released into public waterways, he says. “If you ingest this water, you run the risk of ingesting pathogens which can cause disease."
Pettibone says it can also hurt the environment. Sewage can feed clusters of bacteria that suck up all the oxygen in the water.
“And in some cases where it gets severe, you end up with fish kills,” he says.
May 1 was a particularly bad day for sewage overflow into Lake Ontario, as were a few other days this spring.
But this isn’t a new phenomenon.
The Alliance for the Great Lakes reports that tens of billions of gallons of untreated sewage make their way into the Great Lakes every year. A big part of the problem comes in older cities, where storm water and sewage flow through the same pipes.
Some municipalities are taking steps to curb the issue. Years ago, Monroe County built giant holding tanks to store runoff during rain storms. In a lot of ways, it’s working -- Rochester’s contribution to sewage runoff this spring was less than the other cities.
Toronto, by comparison, has not upgraded its infrastructure in that way. It contributed more than 85 percent of the total sewage released into Lake Ontario on that day in May.
Jim Howe, director of the Nature Conservancy for Western New York, says besides costly infrastructure improvements, there are other ways cities can improve. One is by helping rain stay out of the sewer.
“If we can let it get into the ground and naturally percolate, we won’t have to deal with things like combined sewer overflows," he says. "And you can do things like green roofs, you can do swales along roadways, street trees."
And all that, he says, will help keep Lake Ontario clean.