Southampton Village Details Lake Agawam Cleanup Plan

During the Village of Southampton Board of Trustees meeting on July 23, experts from Stony Brook University and engineering consultant firm CDM Smith unveiled a new proposal to combat the increasing pollution and lethal toxicity of Lake Agawam.

Lake Agawam has for decades suffered from rising levels of microcystin, a potent liver toxin produced by certain species of blue-green algae known as microcystis that have given the lake a distinctive green color. During the recent board meeting, Christopher Gobler, director of the Stony Brook University Center for Clean Water Technology, expressed concern over the rising levels of algae in the lake.

“Just last week, we saw a bloom of nearly 1,000 micrograms per liter of microcystis,” Gobler stated during the trustees meeting. “In 2024, that is the high mark for blue-green algae across the entire state, and we have monitored over 300 other samples. This is a clear and present danger.”

Gobler added that the cause of these harmful algal blooms, according to a variety of studies, appears to be increasing nitrogen levels in the lake, which contributes to the growth of algae and the increased production of microcystin from these blooms. An increase of nitrogen within a lake is usually attributed to outside sources like sewage and fertilizers.

Gobler pointed out that the village has taken measures to reduce nitrogen contamination, such as by combating runoff from roads, but he emphasized that more action needs to be taken. Due to the nitrogen contamination of the lake from groundwater, New York State and village officials have proposed the funding and construction of a Permeable Reactive Barrier (PRB) near Lake Agawam.

“Permeable reactive barriers have been around for decades, so they are not a new technology,” CDM Smith Project Manager Daniel O’Rourke said at the meeting. “They have been used to remove different contaminants from groundwater. Over the past 20 years or so, people have been looking at PRBs to remove nitrate from groundwater.”

The construction of a PRB underground near Lake Agawam will aim to ensure that nitrogen levels within the groundwater are safely reduced before the water enters the lake. As O’Rourke explains, preliminary studies at other PRBs on Long Island, namely in Hampton Bays and Tanbark Creek, have shown promising results in reducing the input of nitrogen from groundwater at lakes. This massive project to help protect Lake Agawam will be funded entirely through the Town of Southampton’s capital project fund.

The proposed project is part of a larger trend to reduce the impact of algal blooms at Lake Agawam, including multiple projects underway to harvest the existing algae at the lake.