Why is Providence’s Largest Pond Invisible?

Mashapaug Pond, Providence’s largest, a deserted idyll in need of love

On Saturday mornings between April and October, a group of volunteer URI Watershed Watch “citizen scientists” collect water samples from Mashapaug Pond in Reservoir Triangle. Mashapaug Pond, the largest freshwater pond in Providence, is part of a complex ecosystem, receiving outflow from Spectacle Pond in Cranston and, in turn, discharging water into the ponds at Roger William Park one mile away.

The pond felt a bit lonely this year. The dragon boat team that used to be a Mashapaug regular apparently has found another place to practice. Occasionally, we pass someone fishing from a rowboat, but most Saturdays the citizen scientist kayakers are alone on the water.

Laura Maxwell taking a water sample    photo: Holly Ewald

Despite the signs that warn, in three languages, that Mashapaug Pond is Sick, and despite the industrial park that butts up against the western shore, the pond nearly always provides what one of our number describes as “our moment of Zen.” I live only a block away, but the pond is another world entirely: swans gliding across the water surface, gentle waves against the kayak. Even the weather feels different, the sun brighter, the breeze cool against your face.

However, the sign warnings are all too true. Mashapaug Pond is on the RI Department of Environmental Management’s (RIDEM’s) list of impaired waters. Fish caught in the pond may be contaminated with PCBs and shouldn’t be eaten. Due to high phosphorous levels, the dissolved oxygen concentration in the water tends to be low, making the pond a poor habitat for fish and wildlife. The phosphorous also contributes to blooms of blue green algae (cyanobacteria), which can affect the health of people and pets who come into contact with or ingest pond water. RIDEM and the RI Department of Health issue cyanobacteria advisories for Mashapaug virtually every summer or fall.

The signs were designed by Holy Ewald, the artist activist behind UPP Arts. UPP Arts has worked with a wide range of artists, scientists, environmentalists, Indigenous communities, and young people on projects aimed at improving the health and vitality of urban waters and the surrounding communities. For ten years (2008-2018), UPP Arts held an annual Urban Pond Procession, complete with fish costumes, rousing bands, and Big Nazo puppets. The Processions often started at Mashapaug Pond, and like, the pond’s water, wound their way to Roger Williams Park, where participants shared food, music, and environmental information, as well as pond-inspired art projects produced in the months leading up the Procession by artists and local youth.

Urban Pond Processions brought attention to Mashapaug Pond. Alvarez High School and Reservoir Avenue Elementary School students learned about the Pond and participated in the processions.

UPP Arts, in collaboration with Brown University’s John Nicholas Brown Center for Public Humanities and Cultural Heritage, conducted a series of oral history interviews to document the history of Mashapaug Pond and nearby neighborhoods. Interviewees described the pond as a center of neighborhood activity in the mid-1900s, with boating, fishing, and even, some say, swimming in the summer and hockey in the winter. This was particularly true before the early 1960s, when West Elmwood, a reportedly close-knit racially mixed neighborhood on the west side of the pond, was razed in the name of urban renewal, to be replaced by the current industrial park.

Some of those recreational activities, like swimming and eating fish caught in the pond, were not a good idea, even then. Industrial facilities, including Gorham Manufacturing on the northeast end of the pond,  had been in operation since the late 1800s, steadily discharging pollutants, including a number of heavy metals; those discharges went largely unregulated until the passage of the Clean Water Act  in 1972. Some of the oral history interviewees remember the pond water as having a green color, even when they were young.

Many Reservoir Triangle residents, including some who live very near Mashapaug, are only vaguely aware of the pond’s existence, or see it only as a danger. But many of the pond’s neighbors are interested in its recreational possibilities. In 1996, the Trust for Public Land helped the City purchase land on the southeast border of the pond, including a building which was used for a community boating program in the early 2000s. The program was reportedly discontinued in 2006, due to concerns about exposure to toxic algae blooms. The building is now used by the Providence Parks Urban Wildlife Refuge Partnership, a collaboration between the U.S. Fish and Wildlife Service, the RI National Wildlife Refuge Complex, the City of Providence Parks Department, and the Partnership for Providence.

Although it is very unlikely that the pond will be safe for swimming in our lifetimes, we citizen scientists are heartened by recent actions to improve the water quality. After Gorham Manufacturing closed in 1985, extensive site remediation was required to clean up or contain the contamination left behind by a century of industrial discharges. Remediation efforts included, in 2015, the excavation of 1-2 feet of contaminated sediment from the floor of Mashapaug Pond cove, the area of the pond adjacent to the factory buildings.

In 2007, RIDEM finalized Mashapaug Pond’s Total Maximum Daily Load (TMDL) for Dissolved Oxygen and Phosphorus. The TMDL is the maximum amount of phosphorus that the pond can receive without causing cyanobacteria blooms that preclude swimming, and producing dissolved oxygen levels that are too low to support fish propagation and other animal life. The report concluded that, at the time of that analysis, 47% of the phosphorous entering the pond was from Spectacle Pond, 22% from six storm drains that convey stormwater into Mashapaug, and 13% from direct overland runoff. The City of Providence is responsible for implementing measures towards achieving the TMDL goal.

In 2014, the US Environmental Protection Agency (EPA), the City, and RIDEM partnered to construct a bio-infiltration system at J.T. Owen’s Park, on the west side of Mashapaug Pond. Bio-infiltration is a green infrastructure best management practice that uses natural processes to capture and treat stormwater volume and pollutants. EPA estimates that, in the first three years of operation of the green infrastructure, the project prevented the inflow of 10.5 million gallons of surface runoff and 16 pounds of phosphorus. It also reduced the inflow of other pollutants, including sediment, bacteria, heat, and nitrogen.

The pond still has a long way to go before it can support unrestricted recreational use and provide a robust habitat for fish and other wildlife. The green infrastructure project has been a success, but it only captures and treats runoff from one side of the pond. And, since almost half of the phosphorus entering the pond is from Spectacle Pond in Cranston, a multi-City approach is needed. On many sampling days this season, water samples taken four meters (about 13 feet) below the surface had 0% dissolved oxygen; an indication that most life cannot be sustained at that depth.

Mashapaug cynobacteria bloom

Here are some ways that you can contribute to better water quality in the state, whether or not you live in the watershed that drains into Mashapaug Pond:

  • Pick up after your pet.
  • Don’t feed ducks and geese.
  • Put waste and litter in trash cans.
  • Don’t pour motor oils, paints, or cleaning products down the street drains.
  • Avoid using pesticides and fertilizers on your lawns.
  • Plant trees, gardens, and grass to absorb and filter runoff – remove asphalt and other non-permeable surfaces where possible

GET INVOLVED: If you would like to become a volunteer water monitor, fill out the form on the URI Watershed Watch website. That site says volunteers must supply their own kayaks or boats, but some established teams, including the Mashapaug groups, have kayaks available for use by monitors. URI provides training and, since the volunteers share the sampling responsibilities, the commitment is limited to a few times in the season. I highly recommend that you consider joining this effort, especially if, like me, you could use a “moment of Zen” on certain Saturday mornings.

Barbara Morin worked for many years for the RI Department of Management and the RI Department of Health. She currently is an Environmental Analyst at the Northeast States for Coordinated Air Use Management. She lives in Reservoir Triangle, near Mashapaug Pond.