When it rains in New England, it pours. 

And when that rain falls in Providence — an urban community built over what used to be a wetland — it tumbles across the city’s wide-ranging impervious surfaces, picking up contaminants along the way. Some of the water sinks into the few absorbent grounds left — marshy lands and green spaces — and the rest flows into combined sewer systems that aim to keep the stormwater out of the rivers.

But when the land and sewers can’t contain surges from storms, the water rushes into the rivers, saturated with bacteria and heavy metals that it picked up along the city’s streets, rooftops, and parking lots. 

From Jan. 1, 2025 to mid-November 2025, Providence saw 41.53 inches of rain — an inch more than normal. In 2023, the city’s accumulated rainfall totaled 58 inches, a significant increase from the 44 inches that used to be the norm. It is scientific consensus that climate change is causing the Earth’s water cycle to become more intense, resulting in more severe single-day events, like pouring rainstorms that increase flood risk.

These rising levels of precipitation hold important implications for human health in the face of climate change — as stormwater runoff seeps into rivers, public health researchers in Boston, for example, have begun linking storm-induced sewage overflow to gastrointestinal illnesses and other issues, such as respiratory irritation and the ingestion of neurotoxins algae and cyanobacteria.

But with something as uncontrollable as a storm, how does monitoring, researching, and adapting to stormwater runoff in Providence work?

On what he calls his “storm sampling days,” Gavin Piccione, a Brown University postdoctoral researcher studying lead exposure in Providence, stakes out the bank of the Moshassuck River, one of two rivers that flow into the Providence River. Piccione stays at his post, outdoors, in the rain, under a tent, from 6:30 a.m. to the late afternoon — and he said he would stay even longer if the batteries in his tools didn’t die.

“The starkness of that change in those data is a motivating factor to keep going, because it’s so amazing to see the chemical data just match up so well with the rain event,” Piccione said.

Taking measurements before, during, and after a storm every 15 minutes, Piccione and his team assess the dynamics of the “chemistry of the river” — how much organic matter, heavy metals, and other materials are in the water at different points of the storm.

These measurements are not the only data point. On a stormy day, the river’s surface rises about 3 feet, the water’s flow accelerates, the metal readings increase about tenfold, and the amount of organic matter in the water dramatically spikes — a likely sign that the large surge in the river height comes from sewage overflow, Piccione said.

“The river gets a lot darker in color, and it starts to smell really bad, and you get essentially like, a hundredfold increase in the amount of trash coming down the river again,” he said.

When sewers overflow, the untreated, contaminated water that washes into the river likely accounts for the elevated bacteria numbers. According to data from the Narragansett Bay Commission (NBC), an organization that manages Providence and Blackstone Valley’s wastewater, higher precipitation has corresponded with increased presence of fecal coliform and enterococci bacteria in the Providence and Seekonk rivers.

For example, the most recent data from Dec. 3, 2025, noted 0.97 inches of precipitation — heavy rain — in the five days prior to the sampling event and overall higher bacteria counts than the previous sampling event on Nov. 19, 2025, which had 0.77 inches of precipitation in the five days prior.

Increased heavy metal concentrations — most notably for Piccione’s project, lead — are more directly attributable to stormwater runoff inundating the rivers than bacteria, but both of these measures are part of the journey of water from the cloud to the river, and eventually, to peoples’ lives.

On a stormy day, the first place water wants to go is pervious ground, what Piccione calls the “subsurface” — think soil, gardens, grass. Less urban areas feature more pervious grounds, so that water and any pollutants soak into the ground. When this subsurface layer becomes “saturated,” like a bucket overflowing, water “percolates” out and into nearby rivers. This overflowed water is usually less contaminated due to the subsurface acting as a “filter” that removes heavy metals.

But in a place like Providence, which “really just has a lot of impermeable surfaces” such as concrete, Piccione said, the process becomes a lot more difficult, and the water overflowing into the river doesn’t get this subsurface filtering treatment. In fact, he attributes the river’s dramatic, quick changes that he witnesses on storm sampling days to the dearth of pervious surfaces and vegetation that could soak up the stormwater. Without pervious surfaces, most stormwater simply skates across the surface.

This doesn’t mean that this water goes directly into the river, though.

When some of Providence’s first sewage systems were built in the 1800s, the norm was to install combined sewers that process stormwater from the street in addition to sewage. But with today’s dramatic influxes in stormwater — the NBC treats up to 300 million gallons of water on a rainy day — combined sewers are no longer the useful solution they once were, according to NBC public affairs manager Jamie Samons.

When more water comes down than these sewers can hold, there are only two options: “You either let that dirty water back up into the streets, into people’s basements, which is not ideal, or you provide a relief point into the closest river so that instead of backing up, it flows out into the river,” Samons said.

To help mitigate the negative effects, the NBC performs “aggressive, aggressive monitoring,” Samons said, of bacteria, nutrients, heavy metals, toxins, and phytoplankton, among other water quality scores. But the organization’s bigger initiative to stop these contamination levels in their tracks is a three-part combined sewer overflow abatement project, which is still in the works, according to Samons.

The first part of this project was a 3,000-feet deep, 3-miles long rock tunnel with a 65-million-gallon capacity under the city, installed in 2008. This tunnel diverts water from combined sewers that would have otherwise overflowed into the river.

Bacteria levels and nutrient levels as well to the rivers in the bay have gone down dramatically. We see portions of the Providence River open to shellfishing that have been closed for over 70 years because the water quality has improved so much.”
— Jamie Samons, Narragansett Bay Commission

Phase two, completed in 2014, brought near-surface water interceptors along the Seekonk and Woonasquatucket rivers to funnel additional combined sewer overflow from those rivers to the tunnel under Providence. The final part is set to be completed in 2028: the installment of a tunnel in Pawtucket and Central Falls similar to the one under Providence.

According to Samon, the completion of the three-part project will facilitate the treatment of about 94% of combined sewage overflow.

“Water always wins,” Samons said. “You cannot build facilities big enough, especially in a time of climate change, that will hold everything.”

While people wait for increased stormwater overflow mitigation installations, people can still protect themselves through more mundane practices such as picking up pet waste, using less nutrient-rich fertilizers, and not feeding ducks and geese, Samons said.

When stormwater has exhausted all of its outlet options — unable to penetrate Providence’s extensive impermeable grounds, brimming to the top of the sewer systems, at capacity in the deep rock tunnels, filling the riverbeds until they have risen several feet — it has nowhere else to go but to flood.

A growing concern among public health scientists is how climate change will impact human health, especially along socioeconomic lines. Marianthi Anna Kioumourtzoglou, a Brown University professor of epidemiology, environment, and society, studies how “ambient environmental exposures impact our health,” including air pollution, severe weather events, and the built environment. According to Kioumourtzoglou, there are “so many different ways that climate change can impact our health,” including less obvious indirect effects.

For example, increased temperatures have a direct effect on human health as the body tries to respond to that environmental change. Sometimes the effects come more indirectly, like a flood that happened before a person even moved into their house leading to mold exposure years later.

But the effects can be even more hidden. Kioumourtzoglou noted that elevated anxiety levels — known to cause “oxidative stress” that has long-term damaging effects on the body — also result from the climate crisis.

For example, Kioumourtzoglou said imagine “there was a flood, there was a hurricane, there was a wildfire, and my property got damaged.” The stress from that, she said, can become even more compounded if “I live in an area that gets frequent wildfires or frequent hurricanes, and then these are becoming more intense, so my stress levels overall are higher.”

Kioumourtzoglou said marginalized communities experience “double whammy” impacts from climate change due to “structural racism, which means they “historically have not been allowed to have a voice in these issues.” This lack of representation causes these communities to have fewer green spaces — which mitigate runoff impacts, as Piccione explained — and more exposure.

“The more disadvantaged communities, because of all the additional stressors that they’re experiencing, which unfortunately means stress about making … ends meet,” Kioumourtzoglou said. The environmental exposures work with the additional stressors to exacerbate health effects “in a synergistic way.”

When devising strategies to help communities navigate climate change, Kioumourtzoglou said a top priority should be understanding how the community interacts with the river.

“You do want the community to have the contact with the river that they want and they need, and that helps the community, and depending on the use you want, to reduce exposure there,”  Kioumourtzoglou said. “So that would be important to bring together water pollution experts, epidemiologists and health scientists, public health experts and community members to understand, what are the exposures in general, what are the exposures that are most relevant for the community?”

Although physical changes like the deep rock tunnels can make sweeping improvements to Providence’s rivers and community health, community education is at the heart of environmental justice. Socially disadvantaged neighborhoods are known to bear the brunt of climate change, but community initiatives like Nuevas Voces, a program run by the Woonasquatucket River Watershed Council to provide education about environmental concerns at a local level, strive to redress some of these harms. 

“Providing people with the information is a really important first step in developing leadership, because once you know about an issue, you can advocate for it,” said Nicole Wright, the community action program coordinator for Nuevas Voces.

Providence neighborhoods such as Olneyville were once hotbeds in the Industrial Revolution — developed as neighborhoods with few trees, dense housing, and legacy contamination from the mills that once dominated the town’s ecosystem. These neighborhoods beg important questions about how the city’s history lives on: “How did each sort of wave of colonization, industrialization, immigration, impact the river and the people that live along the river?” Wright said.

According to Wright, many of the people living in these communities live with flooding as a normal part of life.

“So we talk about how flooding is being made worse by climate change, both due to changing weather patterns,” Wright said. “We have more rain, we have more storms, we have a lot more development of the area and a lot more impervious surfaces. … How that impacts people, and people’s experiences really are related to that,” Wright said.

One of the key goals of Nuevas Voces is to empower those who go through the program by providing them the tools to make positive change — and indeed, according to Wright, Samons, and Piccione, remediation efforts in Providence to lessen the impact of stormwater have proven that when people invest in an issue, it is not for naught.

“What we can see is that Providence was once a poster child for industrialization,” Piccione said. “Of course it takes generations to affect positive change after that. But once those practices are regulated, things can change for the better really quickly.”

This story was published as part of a collaboration between ecoRI News and students in Brown University’s Science Journalism class. The stories examine the science, history, and human experiences connected to the Ocean State’s rivers — from water quality and wildlife restoration to flooding, pollution, social justice, and the communities working to protect them. To read more of these stories, click here.