It’s a measure of just how far the Merrimack River has come that it is news that raw sewage still flows into the river and other New England waterways.
A new report by the New England Center for Investigative Reporting, published in the Sunday Eagle-Tribune, found that 7 billion gallons of a mix of raw sewage and storm drain runoff was discharged into New England rivers and other bodies of water during 2011.
That includes 823 million gallons that flowed into the Merrimack that year, the most recent for which statistics are available.
There was a time, and not that long ago, when the Merrimack was an open sewer. A few more hundred million gallons of sewage and storm water would have made no difference.
The same was true of other rivers that flowed through New England cities, picking up industrial and other waste and emptying it into the sea. The Charles River more than lived up to the title of the ‘60s-era rock song-turned-Red Sox anthem, “Dirty Water.”
But after four decades of work and billions in spending for clean water projects, sewage pollution is now rare enough that it can be quantified.
That’s what NECIR did, using reports required by the federal government to compile the first comprehensive look at the continuing discharges of wastewater.
It found 65 New England cities and towns reported 7,748 discharges through 450 “outfall” pipes in 2011.
Waste spewed into the Merrimack from outfalls in Lawrence, Haverhill and Nashua and Manchester, N.H.
Most of the discharges are the result of a system that collects both sewage and storm runoff in the same network of pipes that deliver the waste to the Greater Lawrence Sanitary District treatment plant in North Andover.
In heavy or prolonged storms, the plant can’t handle the flow and discharges it untreated into the Merrimack.
Significant progress has been made to minimize the pollution.
A series of upgrades costing $17 million increased the capacity of the Greater Lawrence treatment plant more than 40 percent, to 135 million gallons of day, allowing the district to reduce its overflows by more than half.
A second phase of improvements that will cost up to $20 million is planned.
Haverhill has also upgraded its treatment plant to increase capacity, at a cost of $20 million.
The hundreds of millions of gallons of sewage and runoff that still runs into the Merrimack in a year is serious matter and a potential health threat.
But it’s worth nothing that before the sewage treatment plants began to open along the river in the 1970s, the river itself was the sewer system.
A 1963 engineering study concluded the Merrimack was polluted from the New Hampshire border to the sea.
“The pollution resulting from excessive bacterial counts makes any type of recreational use of the river hazardous to the public health,” said the report by Camp, Dresser & McKee.
Today recreational boaters, fishermen and even swimmers along stretches of the river enjoy the reclaimed waterway.
But the report by NECIR is a reminder that more work needs to be done.
“The most important thing for people to become more aware of is we are still using rivers and streams as sewage conveyances,” the executive director of the Mystic River Watershed Association, Ekongkar Singh Khalsa, told NECIR.
“What’s needed now is to look at the great work we’ve done, and redouble our efforts to complete the job.”