From ecoRI News (ecori.org)

When driveways, highways, rooftops, patios and parking lots cover 10 percent of a watershed’s surface, bad things begin to happen. For one, stormwater-runoff pollution and flooding increase.

When impervious surface coverage surpasses 25 percent, water-quality impacts can be so severe that it may not be possible to restore water quality to preexisting conditions.

This where the Seekonk River’s resurgence runs into a proverbial dam. Impervious-surface coverage in the Seekonk River’s watershed is estimated at 56 percent. It’s tough to come back from that amount of development, but the the urban river is working on it, thanks to the efforts of its many friends.

The Seekonk River, from its natural falls at the Slater Mill Dam on Main Street in Pawtucket, R.I., flows about 5 miles south between the cities of Providence and East Providence before emptying into Providence Harbor at India Point. The river is the most northerly point of Narragansett Bay tidewater. It flows into the Providence River, which flows into Narragansett Bay.

While it continues to be a mainstay on the Rhode Island Department of Environmental Management’s list of impaired waters, the Seekonk River is coming back to life.

“I started rowing at the NBC [Narragansett Boat Club] 10 years ago when I realized that I was on the shores really of a 5-mile-long wonderful playground,” Providence resident Timmons Roberts said. “I just think it’s a magical place, and seeing the river come back to life has meant a lot to me.”

The Narragansett Boat Club, which has been situated along the Seekonk River since 1838, recently held an online public discussion about the river’s recovery.

Jamie Reavis, the organization’s volunteer president, noted the efforts that have been made by the Blackstone Parks Conservancy, Fox Point Neighborhood Association, Friends of India Point Park, Institute at Brown for Environment and Society, Providence Stormwater Innovation Center, Save The Bay, and Seekonk Riverbank Revitalization Alliance, among others, to restore the beleaguered river.

“Having rowed on the river for over 30 years now, I can attest to their efforts,” Reavis said. “It was practically a dead river. It almost glowed in the dark back in the day. It is now teaming with life. Earlier this summer, a bald eagle flew less than 10 feet off the stern of my single with a fish in its talons. Watching it fly across the river and up into the trees is a sight I will not soon forget, nor is it one I could have imagined witnessing 30 years ago.”

Decades of pollution had left the Seekonk River a watery wasteland.

In the late 18th and early 19th centuries some of the first textile mills in Rhode Island were built along the Seekonk River. The river, and one of its tributaries, the Blackstone River, powered much of the early Industrial Revolution. Mills that produced jewelry and silverware and processes that included metal smelting and the incineration of effluent and fuel left the Seekonk and Blackstone rivers polluted.

There are no longer heavy metals present in the water column of the Seekonk River, but sediment in the river contains heavy metals, including mercury and lead.

Swimming in the Seekonk River, which doesn’t have any licensed beaches, and eating fish caught in it aren’t recommended because of this toxic legacy and because of the continued, although declining, presence of pathogens, such as fecal coliform and enterococci. The state advises those who recreate on the river to wash after they have been in contact with the water. It also advises people not to ingest the water.

But, as both Roberts and Reavis noted, the Seekonk River is again rich with life and activity. River herring, eels, osprey, cormorants, gulls and the occasional seal and bald eagle can be found in and around the river. The same can be said of kayakers, fishermen, scullers, and birdwatchers.

The river’s ongoing recovery, however, is threatened by rising temperatures, sewage nutrients and runoff from roads, lawns, parking lots, and golf courses in two states that dump gasoline, grease, oil, fertilizer, and pesticides into the long-abused waterway.

The Sept. 30 discussion was led by Sue Kiernan, deputy administrator in the Rhode Island Department of Environmental Management’s Office of Water Resources. She has spent nearly four decades, first with Save The Bay and the past 33 years with DEM, working to protect upper Narragansett Bay.

She spoke about how water quality in upper Narragansett Bay, including the Seekonk River, has improved through efforts both large and small, from the Narragansett Bay Commission’s ongoing combined sewer overflow (CSO) abatement project to wastewater treatment plants reducing the amount of contaminants being dumped into the waters of the upper bay to brownfield remediation projects to the many volunteer efforts, such as the installation of rain gardens and the planting of trees, conducted by the organizations that sponsored her presentation.

She noted that nitrogen loads, primarily from fertilizers spread on lawns and golf courses, that are washed into the river when it rains, lead to hypoxia — low-oxygen conditions — and fish kills. Since 2018, six reported fish kills that combined killed thousands of Atlantic menhaden have been documented by DEM’s Division of Marine Fisheries in the Seekonk River.

Kiernan said excessive nutrients, such as nitrogen, stimulate the growth of algae, which starts a chain of events detrimental to a healthy water body. Algae prevent the penetration of sunlight, so seagrasses and animals dependent upon this vegetation leave the area or die. And as algae decay, it robs the water of oxygen, and fish and shellfish die, replaced by species, often invasive, that tolerate pollution.

While these nutrient-charged events remain a problem, she said, the overall habitat of the Seekonk River is improving. Kiernan noted that in recent years some 20 species of fish, including bluefish, black sea bass, striped bass, scup, and tautog, have been documented in the river.

The Seekonk River is still a stressed system, but Kiernan said the river is seeing a positive trend in its recovery.

“We’re not in a position to suggest that its been fully restored, and honestly I don’t think that we’ll be in a position to do that until we get the CSO abatement program further implemented,” she said. “But I think you can take some satisfaction in knowing that there are days where things look OK out there.”

Frank Carini is editor of ecoRI News.