Sewer Overflows: Heavy Rain, Old Pipes, More People Make A 'Perfect Storm'

In the middle of last month's record heat wave , New York City warned its residents against cooling off in their local waterways. A four-alarm blaze had just shut down the North River Wastewater Treatment Plant in Harlem and raw sewage was spewing straight into the Hudson River.

But what may have appeared a freak situation that was resolved in a few days is actually fairly commonplace, according to experts. More than 27 billion gallons of untreated sewage and polluted wastewater spill into New York Harbor every year, often after as little as one-tenth of an inch of rain overloads the city's antiquated plumbing system that combines waste from homes and businesses with normal stormwater. What's more, the public is often left unaware of these sewer overflows, and sight or smell is not always enough to decipher water quality.

Such news may be particularly unsettling to the thousands of triathletes that braved the Hudson's waters on Sunday, after about half an inch of rain fell on the city the night before. Fortunately, as the New York City Department of Environmental Protection informed The Huffington Post, the Hudson's largest sewer outfalls did not discharge in the hours before the race.

"This is a sleeper issue that the public assumed was solved 20 years ago," Judith Enck, regional administrator for the U.S. Environmental Protection Agency (EPA) Region 2 in New York City, told The Huffington Post. "Larger volumes of sewage, a crumbing infrastructure and heavier rains have created the perfect storm."

New York City is not alone. Older communities across the U.S. sit atop aging combined sewer and stormwater systems, and are subject to increasingly frequent extreme rain events that come with the changing climate .

The federal Clean Water Act has balanced much of this wear and tear over the last 40 years. Required treatment of sewage before it is discharged, for example, means that the effluent coming out of the treatment plants is often cleaner than the water it flows into. Overall, the Hudson River is actually far cleaner today than it was a few decades ago.

"This is an environmental success story. People are using the waterways more than before," said Andrew Juhl, a marine biologist at Columbia University's Lamont-Doherty Earth Observatory in New York. Restaurants today actually advertise waterfront dining, he added, whereas in years past many wouldnt even have had windows facing the unappetizing water.

But as Juhl also noted in an interview with HuffPost, this good news necessitates greater precautions. As water quality improves, more people use the resource and potentially put their health in danger if a plant goes out of service, such as during the recent shutdown, or if rains spark a sewage overflow.

Shortly after raw human waste began spilling into the Hudson, the water watchdog group Riverkeeper went out on the river to test for levels of Enterococcus, a bacterium normally found inside the guts of warm-blooded animals (including people) which indicates the presence of more harmful but less easily measured bacteria, viruses and parasites.

Not surprisingly, the team found "ridiculously high" levels of Enterococcus near where the untreated sewage had been diverted into the Hudson, noted Juhl. On the day after the plant's shutdown, Enterococcus counts reached greater than 24,000 per 100 ml of water. EPA recommends closing beaches for counts greater than 104 to protect public health.

At least three of those with the Riverkeeper expedition got sick that day from exposure to the dirty water.

A few days later, the plant was back to treating sewage and Enterococcus counts in the vicinity fell back to below 10 per 100 ml, well within the federal guidelines. Officials told New Yorkers that they were safe to enjoy their waterways once again.

Meanwhile, that same day, Enterococcus counts in water samples taken near Yonkers, north of the revived Harlem plant, reached nearly 20,000. Rain had fallen around the city the night before, noted Juhl.

"But no one said a peep," he added. "There was no notification to anyone in Yonkers."

Swimmers, kayakers and anyone else in or on the water can't necessarily tell when the water is safe: looks and smells of sewage can be deceiving. Juhl recalled collecting samples of sewage effluent after the Harlem treatment plant went back on-line and noticing that the water looked "kind of nasty." So, he was later surprised when results came back with Enterococcus levels below 10. (He noted that the plant might not yet have been fully operational.)

Juhl contrasted that with a "lovely little creek" that flows through residential neighborhoods and into the Hudson north of the city. Despite looking clear and lacking any odor, Sparkill Creek's water has shown unacceptable levels of Enterococcus at least 85 percent of the time over the last five years.

In other words, the public's safety is highly dependent on the citys or states sampling and reporting, which Juhl suggested is typically "not helpful at all."

The New York Department of Environmental Protection, for example, distributes annual water quality reports a couple years after collection and testing.

"You can find out three years after you were in the water, if that summer, the average indicator of contamination was okay," said Juhl, adding that the department samples in the middle of the river, where the water is much less frequently contaminated and less frequently inhabited by people.

"Given that the city is now encouraging people to use the water system as a recreational resource -- endorsing swim events, giving you a kayak to use for free -- they should do more water quality testing," Juhl noted.

Riverkeeper is helping to fill in gaps by providing information on when and where unhealthy water is most likely to be found. Other independent groups are testing strategies including a network of sensors that keeps tabs on the sewer system and sends text messages to area residents when the need to conserve water is most critical.

"There needs to be more effective communication, alerting the public not to swim in some of these waterways after a heavy rain, Enck said. But more importantly, we need to get to root of the problem and make substantial investments so that at some point in the future we will achieve the Clean Water Act goals of fishable and swimmable water."

The EPA is cracking down on sewers , according to Enck. Two weeks ago, they reached a settlement with Jersey City over violations of the Clean Water Act . The local utilities authority is now required to invest more than $52 million in repairs and upgrades to its existing infrastructure, as well as pay a civil penalty of $375,000. Meanwhile, the cities of St. Louis and Honolulu each agreed on $4.7 billion settlements in recent weeks.

Sewer systems in the Great Lakes region have also been under the EPA's increased scrutiny after this year's severe flooding caused major combined sewer overflows (CSOs) -- sending raw sewage into residents' basements and banning swimmers from beaches. "This appears to be a trend that is only getting worse with increases in precipitation and extreme storms," Joel Brammeier, president and CEO of the independent group Alliance for the Great Lakes, told The Huffington Post.

Like the Hudson River, overall water quality in the Great Lakes as well as in the region's rivers and streams is much better than it was before the Clean Water Act. But "flare-ups of old problems" are particularly troublesome here, added Brammeier, as people often have to "turn around and drink" the water from polluted lakes.

Sewage discharges aren't the only causes of polluted waterways. Surface runoff can sometimes play an even larger role, as evidenced by an ongoing debate in Seattle after last month's proposal to spend more than $1 billion to contain CSOs. Local experts argue that the regions issue is predominantly pet waste , fertilizers and other pollutants that flow into local waterways when it rains.

"Is the pollution from sewage or from dog waste or from gull droppings? There's a whole other tier of activity that agencies are going to need to get into in the future to make the best management decisions," said Patricia Holden, director of the University of California at Santa Barbara's Natural Reserve System.

While sewage and stormwater flow through separate pipes in Santa Barbara, Holden noted that her city also faces challenges due to cracks in aging pipes .

Regardless of the underlying problem, Brammeier suggests that common "grey and green" solutions exist -- from expanding the capacity of wastewater treatment plants to creating green roofs.

But until cities have fully cleaned their dirty water , Juhl recommends that residents avoid going into the waterways after it rains.

Enck added the importance of conserving water at home: "When you flush your toilet on a day with heavy rain, there's a real risk that the human waste will wind up in a river."