For more than a decade, nitrogen pollution has deteriorated water quality in Popponesset Bay, while the city of Mashpee continues to allow hundreds of sewer systems, which are the known source of pollution.
In a report earlier this month titled Cape Cod Polluted Bays: A Decade of Missed Opportunities, the Conservation Law Foundation counts 648 polluting systems in the Popponesset Bay watershed that have passed or been inspected in the past five to ten years Have received approval.
These 648 septic tanks fall in the town of Mashpee and the town of Barnstable. The CLF announced plans in September to sue both cities and the Massachusetts Department of Environment to halt the installation and inspection of wastewater treatment plants.
“At some point we have to draw a line in the sand and basically say that we are not going to continue doing what is causing the problem,” said Christopher Kilian, vice president of strategic litigation at CLF.
The environmental group alleges in the proposed lawsuit that the two cities and MassDEP violate Title V of the Massachusetts Environmental Act every time a sewer system discharging nitrogen-laden sewage is approved or inspected.
The data in the latest CLF report comes from public records that offer only a “mere snapshot” of the total number of wastewater treatment plants approved or inspected in Mashpee over the past decade, Kilian said.
Between November 1, 2018 and July 14, 2020, the city of Mashpee issued 151 septic building permits within the Popponesset Bay watershed, Kilian said. Between March 1, 2019 and July 14, 2020, inspectors passed 212 sewage treatment plants that are contributing to the pollution of the bay, he said.
The remainder of the total number of 648 septic tanks named by the CLF have been allowed or given the green light in Barnstable’s shared section of the watershed, which has provided the CLF with more years of data to date than Mashpee, Kilian said.
The city of Mashpee has long known that nitrogen-laden sewage from septic tanks ends up in the city’s bays and promotes excessive algae growth there. The excess algae overwhelm the aquatic ecosystem by blocking the light required by native plants and consuming oxygen from the water column as the algae break down.
“We see 2009 as a really pivotal turning point,” Kilian said, referring to the year Cape Cod cities and the MassDEP signed the Maximum Total Daily Loads (TMDLs), which are each the maximum allowable nitrogen inputs in the watershed.
The TMDL for Popponesset Bay was completed in 2006.
Today, Popponesset Bay is the most nitrogenous bay in southeast Massachusetts.
Nitrogen pollution has wiped out the growth of seagrass in Popponesset Bay, resulting in the complete collapse of the scallop population and the reduction of habitat for other shellfish species. A slime of rotting algae covers the bottom of the bay and its estuaries, and in early summer masses of macroalgae move with the tide.
“If we were serious about cleaning these bays in this 10-year period, we would hopefully have avoided a lot of pollution and would have been on our way to recovery,” said Kilian.
Instead, “these systems are being audited, allowed every year, year after year, resulting in thousands of opportunities to implement non-polluting systems and programs,” he said.
Mashpee has developed a comprehensive river basin nitrogen management plan over the past decade, the final draft of which was completed in 2015. City officials claim that pollution correcting efforts have grown significantly in importance in recent years.
At the town meeting in June, residents agreed to a debt exclusion for the design of a sewage treatment plant and sewer system to combat water pollution in the Popponesset Bay watershed. Town meeting residents this spring are expected to vote on an estimated $ 51 million package to get this project into construction.
The Mashpee Board of Selectmen discussed the proposed lawsuit in an executive meeting on Monday, 21st December.
“I’m disappointed. I think we’ve been doing the right things specifically in the past few years,” said John J. Cotton, Chairman of the Board of Selectmen, on Tuesday. “To punish us when we finally move forward, that’s what I find not fair.”
Mr Cotton said the CLF’s proposed lawsuit made more sense to him a few years ago when the fight against pollution had less momentum.
“I think the [proposed] The lawsuit has definitely ensured that it remains high on our priority list, “said Cotton of the implementation of the city’s nitrogen management plan. “If you hope so, we’ll do it. It’s high on our priority list. “
Mr. Kilian said: “It is critical and indeed legally necessary that the city move forward quickly.”
However, the city’s current nitrogen management plan “is not 100 percent of the need [nitrogen] Load reductions, ”he said.
Mashpee’s commitment to correcting nutrient pollution needs to be accelerated and further details established, Kilian said.
“I hope we can have productive discussions to avoid litigation,” he said. “But we can’t just ignore the facts and say,” Sure, use a different system like the old one. We know very well that it will pollute. “
Rodney C. Collins, Mashpee City Manager, declined to comment on the potential litigation.