Groundwater is among the Nation's most important natural resources. Nationwide it provides half of our drinking water and is essential to the vitality of agriculture and industry, as well as to the health of rivers, wetlands, and estuaries throughout the country. On Long Island groundwater is the sole source of fresh water for over 2.6 million people.
The use of groundwater on Long Island for supply is affected by local geology and water quality. Natural groundwater discharge sustains the flow of streams, lakes, wetlands, and stabilizes the salinity of estuaries. When large amounts of water are withdrawn from the ground, however, the water table is locally depressed and can reduce the amount of ground water that discharges to streams and salt-water bays. Large-scale sewering practices have also reduced stream baseflow and discharge to salt-water bays. Therefore, water-supply strategies must evaluate the availability of groundwater by considering the corresponding effects of withdrawal on aquatic ecosystems. The suitability of groundwater for human consumption is determined by (1) the quality of water that recharges the aquifer system, (2) the presence of nearby potential sources of groundwater contamination, (3) the presence or absence of saltwater encroachment, and (4) the continual geochemical evolution of groundwater along flow paths.
The purpose of the State of the Long Island Aquifer System web page is to provide a web page devoted to Long Island groundwater resources. This web page gives background and conceptual information about the Long Island aquifer system and also gives a general description of groundwater conditions across Long Island. The tools and resources detailed in each section also include publication citations that guide users to further information.
This web page will be periodically updated to provide an online clearinghouse of Long Island groundwater resources to assist others in evaluating Long Island's groundwater system. As such, the web page gives a general synopsis of groundwater availability and suitability conditions across Long Island. An effort to quantify flow amounts under current (2005-2010) conditions are presented when available and selected case studies of groundwater contamination are shown for several different constituents.
Considerable information is available about the water resources of Long Island as a result of more than 100 years of research by the U.S. Geological Survey (USGS) in cooperation with many other Federal, State, and local partners. Much of this past research was designed to provide the information needed for specific water resource problems on Long Island. However, continued investigations of the islandwide hydrologic system, and the relations between the various components of the system, will help provide the information needed for continued management and stewardship of this important aquifer system.
Other References
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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
Long Island, the eastern-most part of New York State, extends east-northeastward roughly parallel to the Connecticut coastline. It is bounded on the north by Long Island Sound, on the east and south by the Atlantic Ocean, and on the west by New York Bay and the East River.
Long Island - Location and Physical Setting
Long Island Topography
Long Island Population
Long Island Land Use and Land Cover
Long Island Freshwater
Hydrologic Cycle
Long Island Precipitation and Recharge
Long Island Surface Water
Long Island Groundwater
Long Island Hydrogeologic Units
Long Island Fresh and Saltwater Relations/Interactions
Long Island State of the Aquifer System
- Overview
Groundwater is among the Nation's most important natural resources. Nationwide it provides half of our drinking water and is essential to the vitality of agriculture and industry, as well as to the health of rivers, wetlands, and estuaries throughout the country. On Long Island groundwater is the sole source of fresh water for over 2.6 million people.
The use of groundwater on Long Island for supply is affected by local geology and water quality. Natural groundwater discharge sustains the flow of streams, lakes, wetlands, and stabilizes the salinity of estuaries. When large amounts of water are withdrawn from the ground, however, the water table is locally depressed and can reduce the amount of ground water that discharges to streams and salt-water bays. Large-scale sewering practices have also reduced stream baseflow and discharge to salt-water bays. Therefore, water-supply strategies must evaluate the availability of groundwater by considering the corresponding effects of withdrawal on aquatic ecosystems. The suitability of groundwater for human consumption is determined by (1) the quality of water that recharges the aquifer system, (2) the presence of nearby potential sources of groundwater contamination, (3) the presence or absence of saltwater encroachment, and (4) the continual geochemical evolution of groundwater along flow paths.
The purpose of the State of the Long Island Aquifer System web page is to provide a web page devoted to Long Island groundwater resources. This web page gives background and conceptual information about the Long Island aquifer system and also gives a general description of groundwater conditions across Long Island. The tools and resources detailed in each section also include publication citations that guide users to further information.
This web page will be periodically updated to provide an online clearinghouse of Long Island groundwater resources to assist others in evaluating Long Island's groundwater system. As such, the web page gives a general synopsis of groundwater availability and suitability conditions across Long Island. An effort to quantify flow amounts under current (2005-2010) conditions are presented when available and selected case studies of groundwater contamination are shown for several different constituents.
Considerable information is available about the water resources of Long Island as a result of more than 100 years of research by the U.S. Geological Survey (USGS) in cooperation with many other Federal, State, and local partners. Much of this past research was designed to provide the information needed for specific water resource problems on Long Island. However, continued investigations of the islandwide hydrologic system, and the relations between the various components of the system, will help provide the information needed for continued management and stewardship of this important aquifer system.
Other References
_______________________________
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
- Science
Long Island, the eastern-most part of New York State, extends east-northeastward roughly parallel to the Connecticut coastline. It is bounded on the north by Long Island Sound, on the east and south by the Atlantic Ocean, and on the west by New York Bay and the East River.
Filter Total Items: 27Long Island - Location and Physical Setting
Long Island, the eastern-most part of New York State, extends east-northeastward roughly parallel to the Connecticut coastline. It is bounded on the north by Long Island Sound, on the east and south by the Atlantic Ocean, and on the west by New York Bay and the East River. Long Island is joined to the mainland specifically, to the Borough of the Bronx, which is one of the five boroughs of New York...Long Island Topography
The present landforms of Long Island are the result of many geologic processes, some of which began many millions of years ago and some of which began only recently. Most of the major features of the present-day topography, however, are related to the last glaciation, which ended approximately 22,000 years ago.Long Island Population
About 7.56 million people lived on Long Island in 2010. Of these, about 2.50 million are in Kings County, 2.23 million in Queens County, 1.34 million in Nassau County, and 1.49 million in Suffolk County.Long Island Land Use and Land Cover
On Long Island, land use includes the human activities and management practices for which land is used. Land cover is a mosaic of developed, forest, agriculture, and wetlands areas. Both land use and land cover are usually discussed in similar environments. The National Land Cover Database (NLCD) serves as the definitive LANDSAT-based, 30-meter resolution, land cover database for the Nation. NLCD...Long Island Freshwater
Long Island is surrounded by an almost limitless amount of saltwater in the Atlantic Ocean, in the Long Island Sound, and in the many bays bordering Long Island. Although the salty water is important to the economy of the area and is of significant recreational value, this website is mainly concerned with the fresh water of Long Island, which from many standpoints, is even more important than the...Hydrologic Cycle
The water cycle has no starting point, but we'll begin in the oceans, since that is where most of Earth's water exists. The sun, which drives the water cycle, heats water in the oceans. Some of it evaporates as vapor into the air; a relatively smaller amount of moisture is added as ice and snow sublimate directly from the solid state into vapor. Rising air currents take the vapor up into the...Long Island Precipitation and Recharge
Precipitation is water released from clouds in the form of rain, freezing rain, sleet, snow, or hail. It is the primary connection in the water cycle that provides for the delivery of atmospheric water to the Earth. Most precipitation falls as rain. Water seeping down from the land surface and reaching the water table adds to the groundwater and is called groundwater recharge. Groundwater is...Long Island Surface Water
Streams either gain water from inflow of groundwater from the underlying aquifer or lose water by outflow to the underlying aquifer. Many streams do both, gaining in some reaches and losing in other reaches. Furthermore, the groundwater flow directions near any given stream can change seasonally as the altitude of the water table changes with respect to the stream-surface altitude or when rapid...Long Island Groundwater
Approximately 30% of the world’s water is stored as groundwater. Groundwater moves very slowly, on the order of feet per day, however it is still part of the hydrologic cycle. Most of the water in the ground comes from precipitation that infiltrates downward from the land surface.Long Island Hydrogeologic Units
Long Island’s aquifer system consists of a seaward-dipping wedge of mostly unconsolidated stratified sediments comprised of sand, gravel, silt and clay.Long Island Fresh and Saltwater Relations/Interactions
Because saltwater has a greater density than freshwater, fresh groundwater in coastal aquifers will overlie any saltwater that is present in the aquifer at depth (Figure 14).Long Island State of the Aquifer System
One of the most important concepts to understand is that volumes of water pumped from a groundwater system must come from somewhere and must cause a change in the groundwater system. Another important concept is that water table aquifers are hydraulically connected to the streams that drain them. Therefore, pumping water from aquifers that are hydraulically connected with surface-water bodies can... - Data
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