It has been called “Rhode Island’s Big Dig” – a $359 million, 3-mile-long underground tunnel buried more than 250 feet below downtown Providence, the largest infrastructure project in the state’s history.
But that’s where the similarities end between the Narragansett Bay Commission’s Combined Sewer Overflow Abatement Project and Boston’s notorious redirection of Interstate 93 – because Rhode Island’s Big Dig has been completed on time and on budget.
And, unlike Boston’s tunnel, Rhode Island’s is not for people. Ray Marshall, the Bay Commission’s executive director, describes it as “a giant underground subway for sewage.”
The huge new tunnel is the linchpin of the commission’s efforts to curtail the amount of pollution flowing into the state’s waterways from Providence’s 140-year-old combined sewer system, which uses one pipe underneath the streets to catch both residential and commercial sewage as well as rainwater from the streets.
The original system, which will remain in use, works fine in dry weather and wet weather, as long as the rain falls in a slow and steady drizzle. But when more than half an inch of rain falls over the course of 24 hours – which happens about 30 times a year – the Fields Point Sewage Treatment Plant can’t keep up and the sewer pipe gets filled.
To deal with that problem, the city decades ago constructed 66 combined sewer overflows in Providence, Pawtucket and Central Falls. Rather than flow to Fields Point, the untreated waste and rainwater is discharged at those 66 points into Narragansett Bay and the Blackstone, Moshassuck, Providence, Seekonk, Woonasquatucket and West rivers.
Each year, an estimated 2.2 billion gallons of untreated sewage are released into the Bay and the rivers from the antiquated sewer system, according to the commission. That pollution forces officials to close beaches and shellfisheries, and also causes environmental damage – and in 1972, the overflow system was declared illegal under the federal Clean Water Act.
After years of wrangling, the commission decided to construct a new system of underground storage tanks and tunnels that can contain about 65 million gallons of excess sewage during heavy rainstorms. When the storm is over, electric motors will pump the sewage back into the sewer pipes to continue on for treatment at Fields Point. This will reduce by an estimated 40 percent the untreated sewage now dumped into the state’s waterways.
The storage tanks and tunnels were completed last month, and the commission began testing the pumps, gates and other parts of the system on Oct. 31. The plan is to phase the new system in over the next several rainstorms in order to gauge how it works.
Jamie Samons, the commission’s spokeswoman, said the first noticeable impact of the project should be a reduction in the amount of “floatable” pollution, such as toilet paper, plastic bags and condoms, that collect in the water and on the shore after a rainstorm. It also should lead to less street flooding because there will be a place for excess storm water to go.
Eventually, the reduction in pollution should lead to a reduction in the annual number of closures for beaches and shellfisheries. It could allow for an expansion in how much of the Bay is available for public and commercial use, as well.
John Torgan, Save The Bay’s baykeeper, said completion of the tanks and tunnels is an important moment in the long effort to clean up Narragansett Bay. In honor of what it calls “the biggest project you’ll never see,” Save The Bay is holding a celebratory fundraiser – “The Bay Bash: The Light at the End of the Tunnel” – at The Foundry in Providence on Saturday, Nov. 15. (A 6 p.m. “VIP Pre-Reception” will be followed by a 7 o’clock dinner reception, silent auction and the presentation to Narragansett Bay Commission executives of a special Light at the End of the Tunnel Award, Save The Bay said. The main party, which begins at 9, will feature a dessert buffet and dancing to the music of The English Beat and The Cobra-Matics.)
Jody King, vice president of the Rhode Island Shellfishermen’s Association, which has vocally advocated for the project, said it would have an enormous impact on his industry. For years, Upper Narragansett Bay has been closed to fishing about 70 percent of the time, he said. By the summer of 2010, he expects to see that number fall substantially.
“This is the best thing in the world to happen for shellfishing,” King said. “It’ll spread guys out. It’ll give you time to look for product. Now you go to specific little spots, and you never venture off to go look for other ones because you know you’ll only be there for a couple of days” before another closure.
Not everyone agrees that such an enormous project was necessary. Caroline Carp, a senior lecturer in the Center for Environmental Studies at Brown University who has followed the process closely, said that although the result is impressive and will benefit the Bay, better above-ground management practices also could have reduced the amount of overflow sewage during storms. And she questions whether fishing should be expanded in the upper Bay.
“It’s hard not to be excited about it,” Carp said. “On the other hand, it’s important to have somebody voicing some skepticism about whether it’s necessary to go down this path. And I hope we think about it again before we go to the next stage.”
She recommends that a citizens’ group be formed to raise questions and study potential costs of future phases.
Although the now-completed construction of the three-mile tunnel and storage tanks makes up the lion’s share of the Combined Sewer Overflow Abatement Project and are expected to reduce pollution by about 40 percent, they comprise only the first of an envisioned three phases.
Phase II of the project, which is currently being designed, will build two smaller pipes, one along the Seekonk River and one along the Woonasquatucket River, that will be used to transport more overflow sewage into the big tunnel and the storage tanks. Its cost is estimated at about $200 million. Construction is expected to begin in the second half of 2010 and take four years to complete.
Phase III of the project, which would extend pipes and tunnels into Central Falls and Pawtucket at an estimated cost of $350 million to $400 million, is still up in the air. Marshall, the commission’s director, said he hopes a more economical alternative will be found during the next decade.
If all three phases of the project were to be completed, the commission estimates that the 2.2 billion gallons of sewage pollution now being forced into the state’s waterways would be reduced by 98 percent.
The Narragansett Bay Commission had to find multiple funding sources to finance the first phase of the project. Although the state kicked in $26 million and the federal government granted $9 million, the rest was borrowed on the open market and from the R.I. Clean Water Finance Agency.
That means the bulk of the project’s cost will have to be paid back by business and residential ratepayers in their sewer bills. The project already has nearly tripled the average annual sewer bill for a single-family home over the past decade, from $130 in 1996 to $370 this year. The commission says it will take several more years to pay off the debt for the first phase, and then the second phase will need to be paid back, as well.
“Clean water is expensive,” said Samons. •
