The restoration of Farm Pond in Oak Bluffs is underway as last week engineers from two firms began initial survey work on what is hoped will become a widened culvert and a revitalized pond.
On the heels of a Massachusetts Estuaries Project report which calls for a significantly widened culvert to better flush the 42-acre salt pond, last week’s survey work is the first step in a process that Oak Bluffs shellfish constable David Grunden said he hopes will restore this one-time haven for oysters and blue crabs. Over the past few decades the pond has seen nitrogen loading from sources as varied as septic systems, lawn fertilizer and geese. When excess nitrogen, a plant nutrient, enters an ecosystem it can fuel explosive algae growth which robs the water column of oxygen, and fish and shellfish-rearing eelgrass of light.
The estuaries project report on Farm Pond will be presented to the public at the Martha’s Vineyard Commission next Friday, April 29, at 3 p.m. in the Olde Stone Building in Oak Bluffs.
Last week’s work by CLE Engineering and Lloyd Environmental Services, which involved detailed surveys of water depth, salinity, salt marsh monitoring, the dimensions of the current culvert as well as the use of a water jet to determine what sort of sediment lay beneath the pond’s sandy and silty bottom, was in preparation for the construction of a new 16-foot culvert which will replace the current four-foot one. That work will be put out to bid this fall and Mr. Grunden hopes that it will be completed by the end of 2012. The work is being spearheaded and funded by the Massachusetts Ecological Wetland Restoration Office which views the pond as a priority restoration site.
“Back in the 1960s and 1970s the pond was known for oysters,” said Mr. Grunden. “In our monitoring we’ve found a lot of oyster shells but no live oysters. The pond still has a very diverse community now but we’re seeing the stresses of nitrogen loading.”
Those telltale signs include a dense phytoplankton community, epiphtyes on the pond’s plants, and a few invasive species. One species that has become a nuisance in recent years is the Island’s increasingly residential population of Canada geese.
“They stick around all year,” said Mr. Grunden. While one method of restoring the pond is dilution through better flushing, another strategy, unpopular with geese, is eliminating the source. To that end Mr. Grunden said he has been able to get permits to perform egg addling. The method involves coating the birds’ eggs in corn oil so that oxygen can not diffuse through the shell.
“To date we’ve found eight nests around the pond and we’ve addled 38 eggs,” he said. “We’ll be going back in a week or so to addle some more.”
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