Restoring Great Salt Pond
The draft Massachusetts Estuaries Project report on the Edgartown Great Pond obtained by the Gazette last week is required reading for all who live on the Vineyard. The conclusions of the report may be obvious, but no less startling on an Island with a long history of strictly protecting its pristine environment, and they extend well beyond the sandy perimeters of the Edgartown Great Pond: encroaching development and nitrogen escaping from septic systems are polluting Island ponds.
In the case of the Edgartown Great Pond there is an added problem: a plume of nitrogen-rich water that comes from the old Edgartown sewage treatment plant has been creeping toward the pond for years. The plant was upgraded several years ago, so the problem has been corrected. But the old plume will not be fully dissipated until the year 2011, according to the estuaries report. This means the pond historically named Great Salt Pond that once harbored large beds of clams, oysters and scallops, will continue its inexorable march toward eutrophication unless something is done.
And something can be done.
More sewering is the easy answer, but sewering can also have unintended consequences by opening up more development. Sewering is also expensive and sends property tax bills soaring.
At this juncture the decision-makers in Edgartown must act in the broadest possible public interest. A moratorium on all new sewer hookups would be a wise step while the report is studied closely by the town board of health, the conservation commission, the selectmen and the Martha’s Vineyard Commission. The report found that one thousand more houses could be built around the pond at the current zoning rate, although this worst-case scenario does not take into account the braking effects of the Martha’s Vineyard Commission on development.
Nevertheless, limits on future building around the pond should be on the table for discussion. Existing houses around the Great Pond should be mapped with an eye toward upgrading septic systems to nitrogen removing systems. And the board of health has the power to adopt rules requiring any new houses built in the watershed for the Great Pond to use such systems.
This kind of rule-making now has the full weight and good science of the estuaries study behind it. And that has always been the goal of the project: to use sophisticated science and computer modeling to track the source of nitrogen coming into ponds and embayments, and then allow elected officials to use the information to set policy and make rules for environmental protection.
The Edgartown Great Pond report is just the beginning — the estuaries study involves thirteen other Island ponds from Edgartown to Aquinnah. The Great Pond report may be stalled in draft stage for some time, since the contract between the state Department of Environmental Protection and the University of Massachusetts at Dartmouth has expired and remains unsettled.
Meanwhile, it is not too late to save the Island ponds from nitrogen pollution, but it will take good leadership. Thankfully public involvement is high; the riparian owners around the Edgartown Great Pond, who have invested large sums of private money over the years to aid the town in study, are a shining example of such involvement.
More will be needed in the months and years ahead.