Simulation of the Shallow Ground-Water Flow System at Fire Island National Seashore, Long Island, New York

Fire Island National Seashore (FIIS) is located on the barrier island along the extreme southern shore of western and central Suffolk County, New York. Interspersed throughout FIIS are seventeen residential beach communities that in the summer months greatly increase in population due to the arrival of summer residents and vacationers. Wastewater from the numerous homes and businesses in the barrier island communities generally is discharged directly into the shallow ground-water system through use of private septic systems. Contaminants entering the ground-water system can pose a threat to coastal habitats, as they are transported by ground water that discharges to ocean and estuary shorelines.

In October 2004, the U.S. Geological Survey (USGS) and National Park Service (NPS) undertook a comprehensive data collection and modeling program for the shallow ground-water system. This study will increase our knowledge of barrier island hydrogeology, determine the amounts of freshwater discharge and estimate nutrient loads from the shallow ground-water system to estuary and ocean shorelines, and provide a critical tool needed for management of park natural resources.

The objectives of the shallow ground-water study at FIIS are to (1) delineate the boundaries of the shallow aquifer system, (2) identify ground-water flow patterns and rates within this system, (3) determine the amount of freshwater discharge from the shallow ground-water system, (4) evaluate the quality of water in the shallow ground-water system and estimate nutrient loads from this system to coastal waters, and (5) assess current water use and ground-water withdrawal from each aquifer underlying the barrier island.

A USGS Scientific Investigations Report will be produced containing ground-water model-simulation results for FIIS and estimates of nitrogen loading to the ocean and back-barrier estuaries. It also will present a discussion of these results and identify additional research that would contribute to a better understanding of park natural resources needed to evaluate development and management alternatives. Ground-water-level and water-quality data will be compiled and summarized in the USGS' annual Water-Data Reports and be available online through the USGS webpage https://ny.water.usgs.gov/archived_files/annualdata/annualdata.html.

 Project Location by County

Suffolk County, NY