Sewage overflows not only after rain, but snow, too

When talking about pollution from combined sewer systems, which carry sewage and storm water runoff in the same pipes, and overflow into waterways, we often talk about “wet weather” overflows, rather than rain overflows. Sunday night’s snow storm explains why. As snow melts, the melt water infiltrates the same combined pipes, triggering overflows.

Both New York City and the City of Newburgh reported sewage overflows this morning as temperatures rose after a night of rain and a morning of road plowing. In Newburgh, the flow of combined sewage and streetwater was estimated at 5,000 gallons per minute.

These episodes also serve as a reminder that urban stormwater – streetwater, as we call it – is itself full of pollutants, even if it doesn’t cause sewage to overflow. Imagine all that salt spread to keep roads free of ice, and know that much of it just washed off into the Hudson and its tributaries this morning, along with automotive oils, trash and whatever else was on the street.