Sewering the Ocean Heights section of Edgartown could go a long way toward restoring Sengekontacket Pond, a prominent marine scientist told the Martha’s Vineyard Commission this week.

Vast stretches of eelgrass beds have disappeared from Sengekontacket in recent decades and portions of the pond face excess nitrogen loading, mainly from septic systems, said Brian Howes, technical director of the Massachusetts Estuaries Project. On Wednesday afternoon Mr. Howes, representatives from the state Department of Environmental Protection and the University of Massachusetts at Dartmouth-sponsored project presented their findings on the two-town estuary. In October the Gazette reported on a draft version of the report.

Mr. Howes said most parts of the pond were “very healthy” but due to the dramatic loss of historic eelgrass beds, the system was classified as significantly impaired by excess nitrogen. Eelgrass beds serve as a nursery for a variety of fish and shellfish.

Martha’s Vineyard Commission water resource planner Bill Wilcox said that in his monitoring of the pond he had seen promising eelgrass beds smothered by drift wrack algae in recent years. Historic maps dating to 1951 presented in the report show most of the pond was once carpeted by eelgrass. Only a tiny fraction of those beds remain in the very shallowest parts where sunlight is able sufficiently to penetrate the water. Areas of the pond most affected by nutrient overloading are Trapp’s Pond and Major’s Cove. Mr. Howes said the pond could meet its nitrogen threshhold with a 56 per cent reduction in septic load in the Major’s Cove watershed and a 100 per cent reduction of the septic load in the Trapp’s Pond watershed through centralized or decentralized sewering projects.

At the request of wastewater facilities manager Joe Alosso, Mr. Howes also prepared one scenario in which the entire Ocean Heights subdivision in Edgartown was sewered. Although the subdivision does not directly front a portion of the estuary classified as impaired, Mr. Howes said nitrogen from the subdivision eventually accumulated in Trapp’s Pond. Alleviating the nitrogen input from Ocean Heights, Mr. Howes said, could help nutrient loading at Trapp’s Pond and the overall health of the pond and would make sewering houses in the Trapp’s Pond watershed unnecessary. Although the Sengekontacket report is complete, Mr. Howes said his group could run additional scenarios for the two towns for $2,500 to $5,000 apiece.