DEP will hold meeting on cleanup plan for Island ponds

The health of Sengekontacket Pond is threatened, state officials said. — File photo by Ralph Stewart

The Massachusetts Department of Environmental Protection (DEP) will hold a public meeting on Wednesday, Nov. 28, to seek comment on draft reports that identify the need to limit and reduce nitrogen pollution in Farm Pond, Sengekontacket Pond, and Lagoon Pond.

The meeting will begin at 4 pm in the Oak Bluffs Public Library meeting room.

The meeting follows the release of three reports in September that described what is needed to restore the health of the three popular salt ponds, and the grim results if Edgartown, Oak Bluffs, and Tisbury take no action.

State scientists say the ponds may deteriorate to the point where very little aquatic life can survive, boaters will have to navigate through an unsightly algae scum, and shoreline homeowners will have to endure awful smells.

DEP has suggested what action the three towns must take, and offered guidance on how to do it, based on years of scientific study of the three ponds.

The recommendations include a combination of sewering, stormwater management, natural wetlands filtering, and new town bylaws to limit fertilizer use.

Any solution, by necessity, will have to take a regional approach. The Farm Pond watershed is located entirely in Oak Bluffs, but Sengekontacket Pond straddles the border of Edgartown and Oak Bluffs, and Lagoon Pond straddles the border of Tisbury and Oak Bluffs.

According to DEP, aquatic plant and animal life is already affected by the amount of nitrogen getting into all three ponds from natural sources, as well as controllable sources such as septic systems, storm runoff, and fertilizer.

The effects are measured in the loss of eelgrass beds, periodic algae blooms, and lower numbers of aquatic animals.

After measuring and analyzing the ponds for a period of five years or more, state scientists have determined that nitrogen loading is already signficantly higher than levels in a healthy pond, and they have set specific targets that will restore the health of the salt ponds.

According to the Marine Estuary Program studies, an average of 58.8 kilograms (about 130 pounds) of nitrogen enter Sengekontacket Pond every day.

In August, DEP issued reports setting the target levels for Total Maximum Daily Loads (TDML) that would restore the ponds to healthy levels. The reports are in draft form, and they could change, based on public comment.

“The restoration plans for these estuary systems, formulated by MassDEP and the University of Massachusetts/Dartmouth School for Marine Science and Technology (SMAST), are proposed as part of a comprehensive multi-year, collaborative project called the Massachusetts Estuaries Project (MEP), intended to improve estuarine water quality in 70 embayments along the southeastern Massachusetts coastline,” read a DEP press release issued Monday.

“These three coastal water body systems — with watersheds in Martha’s Vineyard — have been found to be impaired for excess nutrients, mainly nitrogen, during the course of MEP technical studies conducted by SMAST. Nitrogen is the primary cause of eutrophication that can lead to: Loss of eelgrass beds, which are critical habitats for fish and macro-invertebrates such as sea worms, snails, clams and crabs; Undesirable increases in macro algae, which are much less beneficial than eelgrass; Periodic extreme decreases in dissolved oxygen concentrations that threaten aquatic life; Reductions in the diversity of sea-bottom-dwelling species such as worms and clams; andPeriodic algae blooms.”

DEP said the primary controllable source of nitrogen is wastewater discharged from septic systems, storm water runoff, leaching lawn fertilizers, and discharges from agricultural land uses.

At the public meeting, DEP staff will present drafts of Total Maximum Daily Loads (TMDLs) for limiting nitrogen to the amounts that each of the ponds can absorb without violating water quality standards and impairing uses such as fishing and recreational activities. The plans call for reducing watershed sources of nitrogen discharged to the three ponds by up to 35 percent. Most of the reductions will be from better treatment and handling of wastewater, but nitrogen from stormwater and fertilizer use should also be controlled wherever possible.

The public comment period ends at 5 pm, January 18, 2013. Written comments can be submitted to: Christine Duerring, Department of Environmental Protection, Division of Watershed Management, 627 Main Street, second floor, Worcester, MA 01608. Electronic format comments should be sent to