Groundwater Monitoring on Long Island, New York and the Five Boroughs of New York City

Science Center Objects

The groundwater data-collection network of the USGS New York Water Science Center, Coram Program Office encompasses data collection from approximately 600 groundwater-monitoring wells on Long Island and in the five boroughs of New York City. Data from these stations are collected in varying frequencies to supply our cooperators, stakeholders, and the public with mission critical information.

The USGS collects groundwater data needed by Federal, State, and local agencies for planning and operating water-resources projects and regulatory programs. On Long Island and in the five boroughs of New York City the USGS operates over 600-groundwater data-collection stations that provide long-term, accurate, and unbiased information that meets the needs of many diverse users.

All project data are served through the USGS National Water Information System: Web Interface (NWISWeb). Graphs and data for each parameter can be displayed or downloaded as needed from NWISWeb. Data are also compiled annually in report form and can be accessed from the USGS Annual Water-Data Reports web pages.

Data-collection frequencies for groundwater stations in southeastern New York generally are: (1) annual-synoptic, which provides data needed for base-line statistical studies and groundwater-model calibration; (2) monthly, which in addition to the above, provides data needed for water-availability and saltwater-intrusion studies, groundwater/surface-water interaction studies, seasonal-trend analysis, and drought and flood monitoring; and (3) continuous-recording or real-time, which provides additional data needed for short-term trend analysis, recharge and tidal variation studies, local groundwater-withdrawal monitoring, and real-time drought and flood monitoring.


Ground water is the sole source of water supply for more than 3 million people on Long Island, New York. Large-scale ground-water pumpage, installation of sanitary-and storm-sewer systems, and frequent variations in precipitation all have significant effects on regional groundwater levels and streamflow. The U.S. Geological Survey (USGS) has operated and maintained a hydrologic-data-collection program on Long Island and in the five boroughs of New York City since the early 1900’s. This program is needed so that a consistent, long-term, islandwide hydrologic data set is available for scientists to properly manage the region’s water resources.

Groundwater data are the primary focus of the USGS data-collection program on Long Island and in the five boroughs of New York City; however, because most streams, ponds, and lakes in the region are hydraulically connected with the shallow groundwater system, the USGS monitors stream discharge and lake levels as part of its hydrologic-surveillance network. Groundwater-level, lake-level, and stream-discharge data are all needed to accurately assess seasonal fluctuations and long-term trends in groundwater storage and climate change.


  • Collect long-term hydrologic data using nationally consistent standards and techniques to provide the information needed to evaluate water availability, salt-water intrusion, drought and flooding susceptibility, wetlands health, and other hydrologic concerns.
  • Supply prompt dissemination of collected data by the USGS online on NWISWeb and in the USGS Annual Data Report.
  • Allow for the production of USGS regional water-table, potentiometric-surface, and depth-to-water maps, used extensively by local agencies, water managers, engineers and consultants, and the public to assess groundwater flooding, contaminant movement, over-pumping, and saltwater intrusion issues across the region.
  • Provide the data needed for other regional and National hydrologic studies.
  • Allow for continuing long-standing ties and exchange of scientific data between the USGS and other Federal, State, and local agencies.

Interactive Groundwater Data Maps for Long Island and New York City

Additional links to regional and statewide groundwater data