The foundation of any groundwater analysis, including those analyses whose objective is to propose and evaluate alternative management strategies, is the availability of high-quality data. Some, such as precipitation data, are generally available and relatively easy to obtain at the time of a hydrologic analysis. Other data and information, such as geologic and hydrogeologic maps, can require years to develop. Still other data, such as a history of water levels in different parts of groundwater systems, require foresight in order to obtain measurements over time, if they are to be available at all.
A key starting point for assuring a sustainable future for any groundwater system is development of a comprehensive hydrogeologic database over time. These data ideally, should include depths and thicknesses of hydrogeologic units from lithologic and geophysical well logs, synoptic and historic water-level measurements to allow construction of pre-development water-level maps for major aquifers (as well as water-level maps at various times during development), groundwater quality analyses to document pre-development and post-development water quality, and simultaneous measurements of streamflow and stream quality during low flows to indicate possible impacts of discharging groundwater to surface-water quality (Alley and others, 1999).
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Table of Contents
State of the Aquifer, Long Island, New York - Introduction
- Precipitation
- NWIS - the USGS Data Archive
- Surface Water - Streamflow
- Groundwater Levels
- Water Table and Surface Maps
- Water Use
- Groundwater Budget
- Inflow to the Groundwater System
- Outflow from the Groundwater System
Below are other science projects associated with this project.
NWIS - the USGS Data Archive
As part of the U.S. Geological Survey's (USGS) program for disseminating water data within USGS, to USGS cooperators, and to the general public, the USGS maintains a distributed network of computers and fileservers for the acquisition, processing, review, and long-term storage of water data. This water data is collected at over 1.5 million sites around the country and at some border and...
Long Island Surface Water - Streamflow
Surface water current conditions are based on the most recent data from on-site automated recording equipment. Measurements are commonly recorded at a fixed interval of 15 to 60 minutes and transmitted by satallite uplink or telephone telemetry to the USGS every hour. Values may include "Approved" (quality-assured data that may be published) and/or more recent "Provisional" data (of unverified...
Long Island Groundwater Levels
Water-level measurements from observation wells are the principal source of information about the hydrologic stresses acting on aquifers and how these stresses affect groundwater recharge, storage, and discharge (Taylor and Alley, 2001). Water-level measurements are made by many Federal, State, and local agencies.
Long Island Water Table and Surface Maps
The depth to the water table can be determined by installing wells that penetrate the top of the saturated zone just far enough to respond to water table fluctuations. Preparation of a water-table map requires that only wells that have their well screens installed near the water table be used. If the depth to water is measured at a number of such wells throughout an area of study, and if those...
Long Island Water Use
The U.S. Geological Survey's National Water-Use Information Program (NWUIP) is responsible for compiling and disseminating the nation's water-use data. The USGS works in cooperation with local, State, and Federal environmental agencies to collect water-use information. USGS compiles these data to produce water-use information aggregated at the county, state, and national levels. Every five years...
Long Island Groundwater Budget
A groundwater system consists of a mass of water flowing through the pores or cracks below the Earth's surface. This mass of water is in constant motion. Water is constantly added to the system by recharge from precipitation, and water is constantly leaving the system as discharge to surface water and as evapotranspiration. Each groundwater system is unique in that the source and amount of water...
Long Island Inflow to the Groundwater System
Precipitation that infiltrates and percolates to the water table is Long Island's only natural source of freshwater because the groundwater system is bounded on the bottom by relatively impermeable bedrock and on the sides by saline ground water or saline bays and the ocean. About one-half the precipitation becomes recharge to the groundwater system; the rest flows as surface runoff to streams or...
Long Island Outflow from the Groundwater System
The flow of water leaving, or discharging, the groundwater system of Long Island occurs naturally through streams, as base flow, at the coastline as shoreline discharge and sub-sea discharge, and through pumping wells as withdrawals. Estimates of each component of outflow from the groundwater system is presented and summarized in this section using streamflow measurements, and a compilation of...
Long Island Water Suitability
Groundwater quality may be affected by natural and human factors (Johnston, 1988). Although the vulnerability of groundwater to contamination from the land surface is influenced by many factors, the degree of aquifer confinement, the depth of the well, and the surrounding land use are primary key factors that influence shallow groundwater quality.
Long Island Water Suitability Case Studies
A collection of studies that focused on the quality of groundwater and surface water, are presented in this section. The reports associated with these areas of water quality concerns are linked as an online source for further reading.
Long Island Groundwater System Potential Hazards
Hazards which may impact the ground water system adversely are presented in this web page. The impacts of these hazards are only shown here as a topic for further discussion and may need to be investigated with further details.
Below are other science projects associated with this project.
NWIS - the USGS Data Archive
As part of the U.S. Geological Survey's (USGS) program for disseminating water data within USGS, to USGS cooperators, and to the general public, the USGS maintains a distributed network of computers and fileservers for the acquisition, processing, review, and long-term storage of water data. This water data is collected at over 1.5 million sites around the country and at some border and...
Long Island Surface Water - Streamflow
Surface water current conditions are based on the most recent data from on-site automated recording equipment. Measurements are commonly recorded at a fixed interval of 15 to 60 minutes and transmitted by satallite uplink or telephone telemetry to the USGS every hour. Values may include "Approved" (quality-assured data that may be published) and/or more recent "Provisional" data (of unverified...
Long Island Groundwater Levels
Water-level measurements from observation wells are the principal source of information about the hydrologic stresses acting on aquifers and how these stresses affect groundwater recharge, storage, and discharge (Taylor and Alley, 2001). Water-level measurements are made by many Federal, State, and local agencies.
Long Island Water Table and Surface Maps
The depth to the water table can be determined by installing wells that penetrate the top of the saturated zone just far enough to respond to water table fluctuations. Preparation of a water-table map requires that only wells that have their well screens installed near the water table be used. If the depth to water is measured at a number of such wells throughout an area of study, and if those...
Long Island Water Use
The U.S. Geological Survey's National Water-Use Information Program (NWUIP) is responsible for compiling and disseminating the nation's water-use data. The USGS works in cooperation with local, State, and Federal environmental agencies to collect water-use information. USGS compiles these data to produce water-use information aggregated at the county, state, and national levels. Every five years...
Long Island Groundwater Budget
A groundwater system consists of a mass of water flowing through the pores or cracks below the Earth's surface. This mass of water is in constant motion. Water is constantly added to the system by recharge from precipitation, and water is constantly leaving the system as discharge to surface water and as evapotranspiration. Each groundwater system is unique in that the source and amount of water...
Long Island Inflow to the Groundwater System
Precipitation that infiltrates and percolates to the water table is Long Island's only natural source of freshwater because the groundwater system is bounded on the bottom by relatively impermeable bedrock and on the sides by saline ground water or saline bays and the ocean. About one-half the precipitation becomes recharge to the groundwater system; the rest flows as surface runoff to streams or...
Long Island Outflow from the Groundwater System
The flow of water leaving, or discharging, the groundwater system of Long Island occurs naturally through streams, as base flow, at the coastline as shoreline discharge and sub-sea discharge, and through pumping wells as withdrawals. Estimates of each component of outflow from the groundwater system is presented and summarized in this section using streamflow measurements, and a compilation of...
Long Island Water Suitability
Groundwater quality may be affected by natural and human factors (Johnston, 1988). Although the vulnerability of groundwater to contamination from the land surface is influenced by many factors, the degree of aquifer confinement, the depth of the well, and the surrounding land use are primary key factors that influence shallow groundwater quality.
Long Island Water Suitability Case Studies
A collection of studies that focused on the quality of groundwater and surface water, are presented in this section. The reports associated with these areas of water quality concerns are linked as an online source for further reading.
Long Island Groundwater System Potential Hazards
Hazards which may impact the ground water system adversely are presented in this web page. The impacts of these hazards are only shown here as a topic for further discussion and may need to be investigated with further details.