State: Improved circulation is key to keeping Nantucket Harbor clean
BY PETER B. BRACE INDEPENDENT WRITER
Department of Environmental Protection officials told Nantucket on Oct. 9 how much more pollution Nantucket Harbor can handle and that increasing water circulation is the most efficient way to clean it up.

Environmental Analyst Michael T. Ackerman from DEP's Basin Planning Section told a crowd of islanders that included many town officials what Nantucket Harbor's total daily maximum load num- bers are, and that the town needs to reduce the amount of nitrogen entering the harbor by up to 53 percent.

Leaking septic system and runoff pollution also need to be curtailed, but increasing the force of water circulation in the harbor by around 15 percent could almost do the entire cleaning job without any reduction in the amount of pollutants entering the harbor, said Dr. Brian Howes, a professor at the University of Massachusetts School of Marine Science and Technology and leader of the Massachusetts Estuaries Project, an analysis of 89 estuaries, harbors and bays in Southeastern Massachusetts from which TMDL numbers were generated.

TMDL numbers (total maximum daily load) represent the highest amount of pollutants - primarily nitrogen, fecal coliform bacteria and runoff - a given water body can absorb and still comply with state, local and federal water quality standards for public health, drinking, swimming and fishing,

Although Dr. Howes did stress that reduction of fertilizer runoff and an educational component should be part of a watershed management plan for Nantucket Harbor, he said stronger tidal flow is key.

"If you can reduce the amount of time water is in there, flush it quicker, it has a directly proportional effect on the loading of the harbor," said Howes. "The number one thing the town should do to protect the harbor is increase the circulation."

Ever an advocate for keeping Nantucket Harbor's main channel and channels leading into the upper harbor and into Polpis Harbor deep and clear, Marine Superintendent Dave Fronzuto said that his plan to improve Nantucket Harbor's jetties by building them higher is already on the move. Last December, he took a step toward boosting circulation in Polpis Harbor by replacing the bulkhead at the apex of Polpis East and West. The bulkhead prevents sand from choking off the channel leading into the western lobe of Polpis Harbor.

Though Howes and Ackerman said Nantucket is looking at a clean-up effort that could take 10 to 15 years, Fronzuto is already working on circulation improvements that Howes said could negate the need for most land-based measures. These include dredging between the sand spits jutting out from the six points on Coatue; filling in the deeper parts of the harbor; the installation of a culvert between the ocean and harbor at the Haulover and building up the height of the jetties.

Having collected historical information on the jetties, Fronzuto said he still needs to meet with the Army Corps of Engineers to discuss rebuilding them. The other options are just ideas at this point.

"I've recommended to the Town Administrator that we need to have a core group of people looking at this: the Conservation Commission, health inspector and the Planning Board," said Fronzuto. "I think a watershed management plan ties into the coastal management plan that the selectmen have as a goal.

"Just like it's time we have a harbor plan and we're working to develop a shellfish management plan, I think a watershed plan is imminent."

Ackerman said that this plan must meet the standards of the Clean Water Act, which mandates the cleanup of all impaired water bodies.

Having broken Nantucket Harbor into four areas - Head of the Harbor, Quaise Basin, Town Basin and Polpis Harbor, Ackerman announced the TMDL numbers for these four quadrants of the harbor.

Ackerman said that the Head of the Harbor could handle 23.03 kilograms of pollutants per day, Quaise Basin could safely take in 64.28 Kg/day, Town Basin could deal with 24.60 kg/day and that Polpis Harbor would allow 30.82 kilograms of pollutants per day.

To get all four parts of Nantucket Harbor back to a clean, life-sustaining level, 57.5 percent of the aforementioned pollution flowing into the Head of the Harbor would have to be removed, 46.2 percent going into Quaise Basin, 32.6 percent running into the Town Basin and 38.1 percent of the bad stuff fouling Polpis Harbor.

Saying that Nantucket is lucky that only 29 percent of this pollution comes from septic systems, with the other 71 percent coming from what he termed land use, Ackerman said getting a plan together to clean up Nantucket Harbor will be easier for the island because there is just one municipality governing the harbor. Along with its completed Comprehensive Wastewater Management Plan, this could also give Nantucket an edge when it develops a clean-up implementation plan and applies for state DEP loans and grants federally funded by the Environmental Protection Agency.

"We look at this a little bit differently from other watershed plans because there is one governing unit," said Ackerman. "What makes things probably a little bit easier is we're not dealing with multimunicipal concerns, but it doesn't mean you don't have different watersheds within

the town itself." I