Today at a regional Water Quality Summit hosted by Suffolk County, New York State Department of Environmental Conservation (DEC) Commissioner Basil Seggos announced the drilling of a new monitoring well in Freeport, Nassau County. The monitoring well is the first of 25 being drilled throughout the region to support the comprehensive groundwater study along Long Island’s sole source aquifer. DEC was directed by Governor Andrew M. Cuomo to install the network of wells and is working in partnership with the United States Geological Survey (USGS) to develop a groundwater model that will help Long Island government officials and water district personnel to make crucial, long-term decisions relating to the preservation of Long Island’s sole source aquifer.

DEC Commissioner Seggos said, “The installation of this well marks a critical step in obtaining the necessary data for the Long Island Groundwater Sustainability Study. This strategically placed network of monitoring wells will help lead to the development of solutions to improve the quality of Long Island’s groundwater and ensure Long Islanders will have plentiful and safe drinking water for generations to come.”

In February 2016, Governor Cuomo announced a series of water quality initiatives, including $6 million to support the development of the Long Island Groundwater Sustainability Study. To execute the study, New York State is partnering with the USGS to examine concerns of over-pumping, saltwater intrusion, plume migration, changes in groundwater outflow to surface waters, and sustainable yield for changing hydrologic stress conditions. The data will help create a groundwater flow model, the international standard for understanding and managing groundwater impacts, for use by the USGS, DEC, Nassau County, Suffolk County, New York City, and other key water-resources management partners in the region. It will enable water managers to collaboratively manage the region's groundwater resources.

The first well, located in Nassau County’s Brookside Preserve along the Freeport and Baldwin border, is being drilled to a depth of 1,300 feet by Delta Well and Pump Company. Drilling at the site began in August, and at least 24 additional wells will be drilled in the future in Nassau, Suffolk, Kings, and Queens counties.

This study aligns with the goals of the Long Island Nitrogen Action Plan, which is a multiyear initiative to reduce nitrogen in Long Island's surface and ground waters by DEC, the Long Island Commission on Aquifer Protection, Suffolk County Comprehensive Water Resources Management Plan, and other partners.

Senator Todd Kaminsky, Chair of the Senate Environmental Conservation Committee, said, “Long Island’s aquifers are an essential part of our Island. The start of this study signals an important step toward understanding our aquifer system so that it can be preserved for future generations.”

Suffolk County Executive Steve Bellone said, “Suffolk County is taking an active role to protect water quality and preventing potential threats from harming our critical aquifer system. I applaud Governor Cuomo and DEC for continuing to work with us and implementing this study to further improve our understanding of our groundwater resources and safeguard the region’s water supply.”

Nassau County Executive Laura Curran said, “Drinking water is a precious resource. The new well in Freeport will enable the USGS to comprehensively study groundwater to test the quality and assess the health of our aquifer.  I thank Governor Cuomo and the DEC for continuing to work to protect our drinking water on Long Island.”

Importance of Groundwater on Long Island

Most of Long Island is entirely dependent on the underlying sole-source aquifer system, which currently supplies more than 400 million gallons a day (MGD) of freshwater from more than 1,500 public supply wells to over 2.8 million people in Nassau and Suffolk counties.

Long Island’s aquifer system is comprised of several freshwater zones, or “aquifers,” generally ranging in increasing depth from the upper glacial, North Shore, Jameco, Magothy, and the Lloyd aquifer. Several major clay layers are also present and influence the aquifer system in several ways:

• They act to confine and isolate the underlying freshwater zones;
• They limit the rate of recharge to the units below;
• They protect the underlying freshwater from surface contaminants; and
• In coastal areas they influence the formation, location, and movement of the freshwater/saltwater interface.

In some areas of Long Island, freshwater pumping has resulted in saltwater intrusion into the aquifer system and has also impacted streams, ponds, and coastal wetlands and estuaries that rely on groundwater discharge to sustain them. Additional human-related activities, such as urban runoff and septic systems have also affected the water quality of the aquifer system. One of the main concerns facing the aquifer and that this study seeks to better understand is saltwater intrusion. Long Island is surrounded by saltwater at the surface and at varying depths below ground. The freshwater that replenishes the aquifer system slowly flows through it and eventually exits the aquifer system at the coast, keeping saltwater in the sediments that are offshore from pushing landward beneath Long Island.

The area where the fresh groundwater flowing seaward to the coast meets the salty groundwater flowing landward toward the shore is referred to as the freshwater/saltwater interface. If too much fresh groundwater is pumped from an aquifer near this interface, salty groundwater will move inland, affecting the water quality in wells near the interface. If a pumping well pulls in salty groundwater by the process referred to as saltwater intrusion, that water is no longer safe to drink. Once intruded, an aquifer cannot provide drinking water until the saltwater is flushed out naturally by freshwater, which can take decades to as much as centuries.

The island-wide groundwater model will also be a powerful tool in addressing legacy and emerging contaminant water quality issues. For example, a focused version of the USGS Long Island regional groundwater flow model was used to support the development of remedial alternatives for the proposed plan announced by Governor Cuomo for the full hydraulic containment of the Navy Grumman groundwater plume in Bethpage.

For more information about the study, please go to the USGS Groundwater Sustainability of the Long Island Aquifer System website.