For decades, Farm Pond in Oak Bluffs has been closed to shellfishing, as excessive nitrogen and bacteria accumulated in the salt water.

Largely cut off from the sea, the 42-acre pond, known to many by the sea serpent that floats there each summer, is murky and stagnant.

But salvation may not be far off.

The town has learned that it’s in the running for major federal funding to widen an existing culvert under Sea View avenue, and restore tidal flushing to the pond.

Oak Bluffs is eligible for about $1 million in funds under the Estuary Restoration Act, though a contract for the grant has not yet been awarded.

“It is very exciting to see that we are close to negotiating a potential award,” said Franz Ingelfinger, a restoration ecologist with the state who helped the town apply for the grant. “It would be a tremendous benefit to the project and to the community.”

The project would involve replacing the existing four-foot inlet with two eight-foot culverts, to accelerate the flow from pond to sea. Although it was identified years ago, lack of funds put this relatively easy fix out of reach.

Now, the town is looking for sources for a required 35 per cent local match, which may include grants, community preservation funds or bonding out of town coffers.

If funded, the project would be the culmination of decades of efforts to revitalize the pond. Shellfish constable David Grunden estimates that more than $300,000 has gone into Farm Pond in the last 10 years. “We have done quite a bit of work, and our funding sources have been numerous,” he said.

The pond’s major problems began in 1984, when a storm pushed washed sand over the Harthaven harbor footbridge, stifling the only channel. Today, while recreational activity flourishes in neighboring Sengekontacket Pond, Farm Pond is quiet, even in the height of summer.

“You go past Farm Pond and there is nothing going on there, there is one small dock, and that’s it,” said Mary Carman, research scientist at the Woods Hole Oceanographic Institution, who has been studying the pond since 2011. “There is no recreational activity and no shellfish activity.”

Excessive amounts of nitrogen, which came mostly from nearby septic systems, has triggered dense plant growth through a process called eutrophication. “It’s very murky, very soupy,” Ms. Carman said. “If you try to stand up, your feet just sink in the soupy mud.” She is in the midst of a study that will track the health of the pond over five years.

Another indicator of the pond’s ailment is the decline of eel grass, an underwater plant that prefers clear water. In 2004, Farm Pond won designation on the state’s wetlands priority list, and with it, Mr. Inglefinger’s expertise.

Since then, the pond has been studied from all angles. An ever-growing body of knowledge about Farm Pond saw contributions from the town, the Martha’s Vineyard Commission, National Oceanic and Atmospheric Administration, the state environmental trust and the Community Preservation Act, among others.

In 2010, the Massachusetts Estuaries Project released a study that showed moderate nitrogen loading and pointed to a decline in the eel grass and marine life. The report said water quality would be improved with the installation of wider, larger culverts.

“The computer modeling that has been already done is predicting that with a greater tidal flushing, we will have the nitrogen levels well below the critical threshold,” Mr. Grunden said. “That should eliminate any need for the town to sewer over at the Farm Pond watershed.”

The estuaries act is one of the last large opportunities for funding to finance the project, Mr. Ingelfinger said, adding that the town had exhausted some other federal alternatives. “If the funding is awarded, it would be a tremendous benefit to the town and the community, and that would be quite exciting,” he said.

When scientists peer into that future, they see good things for Farm Pond, they said. The eel grass population will grow back, the water will run clear and the pond may even open again to shellfishing.

Then, David Grunden can check a major item off his to-do list.

“My wife told me I couldn’t retire until I got Farm Pond fixed,” Mr. Grunden said with a laugh. “Now there is a light at the end of the tunnel.”