Recreational use of the Delaware River and other waterways in its basin are threatened by combined sewer overflows, a new report says. Photo by Chris Mele
Recreational use of the Delaware River and other waterways in its basin are threatened by combined sewer overflows, a new report says. Photo by Chris Mele

15 billion gallons of raw sewage yearly is released into Delaware River watershed, report says

| August 7, 2023

Overflows from Philadelphia’s combined sewer system send an average of 15 billion gallons of raw sewage and polluted stormwater each year into local rivers and streams, including the Delaware and its tributaries, according to a new report by the PennEnvironment Research & Policy Center.

Those overflows diminish recreational opportunities on the waterways, expose paddlers, anglers and swimmers to pathogens that can make them sick, and subject fish and wildlife to toxic substances, the report found.

“From the tiniest tributaries of the Schuylkill to the mighty Delaware, people love to walk, hike, boat, fish and sometimes even swim in and around Philly’s amazing waterways,” Stephanie Wein, the clean water advocate at PennEnvironment, said in a news release. “While the city has made efforts to address the massive flow of raw sewage, this problem still puts public health at risk on far too many days of the year.”

However, in a written rebuttal that was even longer than the PennEnvironment report itself, the Philadelphia Water Department suggested that there was not a magic plunger it could wave to make the pollution disappear all at once. 

The department highlighted the strides it’s made over the years in reducing the overflows and said PennEnvironment report’s recommended remedies were unrealistic, noting that replacing the entire combined sewer system “would be prohibitively expensive and infeasible.”

Read more: Efforts to improve dissolved oxygen in the Delaware and make life better for the Atlantic sturgeon hinge on better wastewater treatment

Why overflows happen

Roughly 60 percent of Philadelphia is served by a so-called combined sewer system.

That is a setup in which stormwater (what is collected in street drains from rains) and sewage (what is sent from toilets and other sources) flow through the same pipes to a wastewater treatment plant.

When rainfall overwhelms the treatment systems’ capacity, as can happen in periods of intense localized storms and flooding, raw sewage mixes with stormwater and flows untreated into waterways. 

In an era of climate change, immense storm events, like the July flooding in Houghs Creek in Bucks County, Pa., that claimed the lives of seven people, can be expected to become more frequent.

This video was shot at the combined sewer overflow outfall T7, at Tabor Road, west of Tacony Creek, on July 8, 2019. Video courtesy of Tookany/Tacony-Frankford Watershed Partnership.

Lost recreational opportunities

Sewage and runoff pollution often contain pathogens that can pose health hazards for people playing on the water, including nausea, diarrhea, ear infections and rashes, according to the report, which was released last month. 

Contaminated overflows can linger in waterways for up 72 hours after a storm, meaning that the amount of time lost for recreational use extends beyond just the immediate contamination event, the report said. 

PennEnvironment researchers, relying on combined sewer overflow data from the Philadelphia Water Department from fiscal years 2010-2022, calculated an average of 64 overflows per year. The report conservatively estimated a loss of recreational access, per overflow event, of 24 hours, which, in turn, translated to a loss of at least 128 days a year.

The report said water recreation points among waterways were the frequent sites of the overflow pollution, including Bartram’s Garden, Tacony Creek Park and several locations along the Delaware.

“Unfortunately, because of the CSOs that impact the river around us, the sewage and pollutants create unsafe river conditions and require us to cancel on a frequent basis —about a quarter of our programs,” said Valerie Onifade, the river program director at Bartram’s Garden. 

Researchers could not qualify when those overflows and losses occurred. It was unclear whether those lost days fell exclusively during the spring, summer and fall, when recreational use would be at its highest, or whether some of them happened in the winter.

Well ahead of modern regulations, untreated raw sewage was regularly discharged into the Delaware. 

A 2022 exhibit, “We All Live Downstream,” at the Science History Institute in Philadelphia, noted that centuries ago, industrial wastes from making candles, soap and leather were routinely dumped into the Delaware. In the 1700s, Philadelphia’s bustling port “reeked of rotting garbage at low tide,” it said. 

Decades ago, combined sewer systems were the standard operating plans of their times. It wasn’t until the advent of the Clean Water Act in 1972 that consistent strides were made to improve water quality. The Delaware River Basin Commission has been engaged in a yearslong effort to raise the levels of dissolved oxygen in the Delaware to benefit fish and wildlife.  

Read more about the water quality of the Delaware River watersheds in Pennsylvania. 

Call for action

PennEnvironment called for “bolder action” to make local waterways consistently clean for recreation. 

Among its recommendations: Expand the deployment of netting to capture sewage solids and other waste from combined sewer overflows; more rapidly deploy green infrastructure to capture stormwater; and aggressively go after clean water funding that is now available.

PennEnvironment acknowledged that the Philadelphia Water Department “has reduced sewage pollution to a degree,” but added that at the department’s current rate of progress, “Philadelphians will, under the best of circumstances, be waiting for decades before their rivers and creeks are clean enough for full recreation.”

Read more: The cost for the Delaware River to be as clean as possible goes from $1.5 million for Trenton to as high as $3 billion for Philadelphia, according to a report.

PWD responds

The Philadelphia Water Department acknowledge PennEnvironment’s “continued passion for our mission to achieve clean and healthy rivers and streams.” Having said that, the department pushed back against the group’s report, saying it overlooked or minimized initiatives already in place.

For instance, the PWD noted that it has projects under construction to reduce combined sewer overflows by an additional 600 million gallons each year in the next three years. Further, the department said, the report does not consider the complexities of the PWD’s “Green City, Clean Waters” initiative, an ambitious, multi-year effort. 

“It is simply not realistic to move the goalposts on a massive, 25-year initiative at the halfway point to dramatically increase the implementation pace or add new projects,” the department wrote. “Even if funds were unlimited, the resources to support acceleration are not. It would likely take more than a decade to plan, design and implement the drastic changes to Green City, Clean Waters that are being alluded to.”

The department said it has already committed more than $4.5 billion to infrastructure improvements through fiscal year 2029, with $1 billion of that earmarked for combined sewer overflow mitigation.

The department added that funding alone would not solve everything, noting that projects can be complicated by regulations, changing real-world conditions and the economic climate. 

“Even if we were to receive the entire state-wide allocation Pennsylvania is expecting for sewer investments from the Bipartisan Infrastructure Law over the next four years, it would still only be a fraction of the funding needed for the magnitude of improvements required to mitigate all combined sewer overflows stemming from our aging sewer system,” the department wrote.

Chris Mele

Chris Mele

Chris Mele is a reporter and editor with more than 30 years of experience in news, specializing in investigative and enterprise reporting.

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