‘An upward direction’ for the Delaware River: UPenn researchers recommend ways to make swimming safer

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Many older cities, such as Philadelphia and Camden, struggle to meet the federal Clean Water Act requirements of having “swimmable” waterways because of outdated sewer systems.

The Delaware River often contains fecal bacteria levels that make it unsafe to swim, fish or even kayak. That’s because stormwater and sewage often flow through the same underground pipes. During heavy rain, the system can overflow, spilling sewage into the region’s rivers and streams.

Researchers at the University of Pennsylvania’s Water Center have evaluated fecal bacteria levels in the Philadelphia, Chester and Camden region of the Delaware River. The study found that costs to upgrade this older infrastructure are a significant barrier to achieving swimmable water, and offered recommendations to improve water quality in a cost-effective and timely manner.

“It’s important to know how far we’ve come, and how far we still need to go, to make the Delaware River fishable, swimmable and drinkable,” said Howard Neukrug, executive director of UPenn’s Water Center.

Prior to the federal Clean Water Act, the Delaware River between Trenton and Philadelphia supported virtually no life at all. More than 50 years ago, regulations changed what was once a “stinky, ugly mess” into a place where hundreds of thousands visit its urban shorelines each year. Treatment plants along the Delaware and Schuylkill rivers provide clean drinking water to about 15 million people. However, urban parts of the Delaware River and its tributaries, like the Schuylkill and Wissahickon, are still too polluted to swim in.

Swimming and kayaking is permitted in much of the Upper Delaware River, which is regulated by the Delaware River Basin Commission. However, for a 27-mile stretch along Philadelphia and Camden, the DRBC restricts residents to boating and fishing.

The UPenn study, which was done in collaboration with other academic institutions, nonprofits and regulatory agencies, found bacteria levels in the Delaware River varied across sites, and by month. Water quality conditions generally were worse during wetter months, and overall, the highest levels of fecal bacteria were found within 2,500 feet of a combined sewer outfall — large underground pipes that empty stormwater into streams like the Wissahickon, and rivers like the Schuylkill and Delaware.

The study found that fecal coliform levels are much higher along the shoreline than in the center channel. That’s partly because pollution gets caught along the edges, Neukrug said.

“Where you want to swim is also where the [bacteria] numbers are the highest,” he said.

More data is needed to determine where fecal bacteria comes from, where it’s going and how long it remains in the water, Neukrug said. Understanding these factors is challenging because the tide in the Delaware River shifts bacteria back and forth, he said.

Investing in stormwater infrastructure

State and federal regulations require cities to reduce 85% of stormwater and sewage overflow, and significant progress has been made, according to the report. The Camden County Municipal Utilities Authority, the Delaware County Water Quality Control Authority and the Philadelphia Water Department have set aside millions of dollars to make capital improvements to their sewer systems.

For instance, in 2011, PWD launched a 25-year plan, known as Green City, Clean Waters, to reduce the amount of sewage entering the city’s waterways by using green infrastructure and expanding stormwater treatment capacity. The department said it has reduced overflows by 3 billion gallons by utilizing technology composed of natural elements such as rain gardens to soak up stormwater.

PWD recently received $25 million in federal ARPA funds — the $1.9 trillion COVID relief bill President Biden signed nearly three years ago. PWD will use $15 million to fund a new pretreatment building at the Northeast Water Pollution Control Plant, which will reduce combined sewer overflows by an additional 600 million gallons annually in the next three years.

  • January 27, 2024
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