Georgica Pond: Climate Change Indicator?

Fertilizers, septic seen as culprits in cyanobacteria bloom
The trustees have advised people who use Georgica Pond to keep children and pets away from algae blooms and scum and to rinse with clean water if they are exposed. Morgan McGivern

Multiple causes and conditions are responsible for the poor health of Georgica Pond, and multiple measures must be taken to improve water quality there. This was the conclusion of a meeting last Thursday that brought together representatives from East Hampton Town and Village, including the East Hampton Town Trustees, as well as the Nature Conservancy, a research scientist, and an environmental consultant.

The trustees, who manage most town waterways on behalf of the public, closed the pond to crabbing and the harvesting of other marine life on July 24 after the discovery of cyanobacteria, or blue-green algae, which can be harmful to people and animals. They advised against swimming or wading near blooms or surface scum, drinking the water, or allowing children or pets near blooms and surface scum. At their meeting on Aug. 12, the trustees unanimously voted to extend the closure through Tuesday. 

Cyanobacteria blooms typically form in nutrient-rich waters during hot, calm weather, according to the New York State Department of Environmental Conservation. In 2012, a dog died after it was believed to have ingested water from the pond. Its owners were among the shoreline property owners that attended the trustees’ Aug. 12 meeting to voice their concerns about the pond’s health.

East Hampton Town Supervisor Larry Cantwell said that one result of last Thursday’s meeting was a decision to prepare an outline of management measures that the town, village, trustees, and private property owners should take. A draft document will be prepared and circulated “within the next several weeks,” Mr. Cantwell said.

Also at the meeting was Pio Lombardo of Lombardo Associates, an environmental consulting and engineering firm that is preparing a comprehensive wastewater management plan for the town. Mr. Lombardo pointed to fertilizers and septic systems as the likeliest primary factors contributing to the cyanobacteria bloom in the pond. He described his assessment as preliminary, but said, “the issue is excess nitrogen or phosphorus getting into the pond, as best as we can tell. There’s also a question regarding the influence of bottom sediments that needs to be scientifically determined.”

On large lots, Mr. Lombardo said, landscape fertilization “can bemuch greater than even the wastewater contribution. We’ve done that type of footprint analysis in terms of the likely discharges of nitrogen from properties based on lot size and typical fertilization rates. As the lots get bigger . . . it becomes the significant factor — not to diminish that dealing with wastewater is critical as well.”

Diane McNally, the clerk of the trustees, who also attended the meeting, said that an excavation permit from the D.E.C. to allow dredging was the “largest and most obvious project” to mitigate the environmental injuries to the pond. “When you dredge the channel, you want to go from deep water to deep water in any body, so when the pond is open it can really drain.”

Mr. Cantwell said that an expedited excavation permit-renewal application was discussed at last Thursday’s meeting. “Apparently, the D.E.C. is requesting more information than in the past, a lot more information . . . requiring study and analysis in order to qualify for the permit,” he said. “We’re going to work our way through that.” Another challenge, said Mr. Lombardo, is cost. “Disposal of dredge material can be quite expensive,” he said.

The trustees open the pond to the Atlantic Ocean on a biannual basis, on or around April 15 and Oct. 15. “But we have noted of late that the spring opening has been getting earlier,” Ms. McNally said, based on water temperature and fish migration. “It’s been earlier than April 15 in the last few years, and a bit later in October. Our weather patterns are changing a bit.”

“In general, we are seeing that climate change is having an influence,” Mr. Lombardo said. “Water temperature is important: At higher temperatures, one sees higher algae growth rates, and less desirable algae species.”

“We need to move as quickly as possible,” Mr. Cantwell said. “There may be multiple methods to mitigate, but that doesn’t mean we should be overwhelmed by it.