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.
Saltwater Occurrence and Intrusion in the Aquifers of Long Island, New York
Freshwater on the island discharges along most of the periphery of the island, which prevents saltwater from entering the aquifers. In western Long Island, however, saltwater wedges that are hydraulically connected to the sea are found in aquifers on the Atlantic Ocean side of the island. The saltwater wedge in the Lloyd aquifer extends seaward of the wedges in the overlying aquifers because of the relatively impermeable clays of the Raritan confining unit, and the high potentiometric head in the Lloyd Aquifer, which force freshwater in the Lloyd aquifer to extend seaward of the island (figure 29). The positions of the saltwater wedges have been attributed mainly to natural conditions that prevailed long before the start of groundwater development in western Long Island. Groundwater pumping, however, has caused a landward migration of the freshwater-saltwater interface in aquifers in western Long Island since the late 1890s (Lusczynski and Swarzenski, 1966; Buxton and Shernoff, 1999). Saline groundwater is also probably migrating downward into the Lloyd aquifer from the overlying Jameco and Magothy aquifers in areas of heavy pumping. In the Forks areas of eastern Long Island, saltwater underlies freshwater in lens-shaped reservoirs that resemble those that underlie outer areas of Cape Cod, Massachusetts (Nemickas and Koszalka, 1982).
Recent investigations which focused on saltwater concerns within public supply system are presented in Stumm (2001) and Stumm & others (2002).
Pesticide Occurrence
Pesticide-Related Chemicals Detected in Long Island Groundwater 1996-2010
by USGS, SCDHS, and SCWA:
Detailed water quality monitoring data, from monitoring conducted by Suffolk County and the U.S. Geological Survey, are available in a document titled “Water Quality Monitoring for Pesticides, Historical Monitoring Data for the Long Island Pesticide Pollution Prevention Strategy”. Datasets in that document indicate minimum, maximum and median concentration levels of pesticides and degradates detected from about 1997 to 2011.
Source: Link to Online Report
The U.S. Geological Survey (USGS) National Water Quality Assessment (NAWQA) program is designed to assess the status of the Nation's water quality, describe trends in water quality, and provide a sound scientific understanding of the primary natural and human factors that affect the quality of the Nation's water resources. One component of the NAWQA program is the study of pesticides to determine their occurrence, concentrations, and seasonal variability in surface and groundwater throughout the country. The study was conducted as part of the Long Island-New Jersey (LINJ) coastal drainages NAWQA project. The LINJ study area is one of 59 areas studied nationwide.
Source: Link to Online Report
The NAWQA Pesticide National Synthesis Project, which began in 1992, is a national-scale assessment of the occurrence and behavior of pesticides in streams and groundwater of the United States and the potential for pesticides to adversely affect drinking-water supplies or aquatic ecosystems.
Source: Nawqa report
Source: Nawqa fact sheet
Nitrogen Loading
Although nitrogen is abundant naturally in the environment, it is also introduced into aquifers through sewage and fertilizers. Chemical fertilizers or animal manure is commonly applied to crops to add nutrients. It may be difficult or expensive to retain on site all nitrogen brought on to farms for feed or fertilizer and generated by animal manure. Unless specialized structures have been built on the farms, heavy rains can generate runoff containing these materials into nearby streams and lakes. Wastewater-treatment facilities that do not specifically remove nitrogen can also lead to excess levels of nitrogen in surface or groundwater.
Several USGS investigations have evaluated the nitrogen loads and trends entering Long Island's surrounding estuaries from groundwater and surface water. Trends in nitrogen concentration and nitrogen loads entering the South Shore Estuary Reserve (Monti and Scorca, 2003) were evaluated on 13 major south-shore streams in Nassau and Suffolk Counties, Long Island, New York with adequate long-term (1971-1997) water-quality records. Furthermore, 192 south-shore wells with sufficient water-quality data, were selected for analysis of geographic, seasonal, and long-term trends in nitrogen concentration. An example of the long-term trend in one of the 13 streams is shown in figure 30.
Seasonal and long-term trends of nitrogen loads entering Long Island Sound from groundwater and streams on Long Island, New York were analyzed for four major streams on the north shore of Long Island that have long-term discharge and water-quality records for the period 1985-1996 (Scorca and Monti, 2001).
Volatile Organic Compounds
Volatile Organic Compounds (VOCs) "are organic compounds that can be isolated from the water phase of a sample by purging the water sample with inert gas, such as helium, and, subsequently, analyzed by gas chromatography. Many VOCs are human-made chemicals that are used and produced in the manufacture of paints, adhesives, petroleum products, pharmaceuticals, and refrigerants. They often are compounds of fuels, solvents, hydraulic fluids, paint thinners, and dry-cleaning agents commonly used in urban settings. VOC contamination of drinking water supplies is a human-health concern because many are toxic and are known or suspected human carcinogens — (U.S. Geological Survey, 2005).
Source: Nawqa Reports on VOCs analysis.
Pharmaceuticals Occurrence
In 2002, the U.S. Geological Survey (USGS), in cooperation with the Suffolk County Water Authority (SCWA), began a 4-year study to document the occurrence of pharmaceutically active compounds in groundwater wells throughout Suffolk County. Benotti and others (2006) collected seventy (70) water samples from 61 wells in the upper glacial and Magothy aquifers (9 wells were sampled twice) during 2002–2005 and analyzed for 24 pharmaceuticals. Wells were selected for their proximity to known wastewater-treatment facilities that discharge to the shallow upper glacial aquifer. Of the 70 samples taken, pharmaceuticals were detected in 28, of which 19 contained one compound, and 9 contained two or more compounds. The report summarizes the results from the study and relates the concentrations and frequencies of detection to those reported from a 1998–2000 nationwide study of streams that receive wastewater (Kolpin and others, 2002).
Perchlorate Occurrence
Perchlorate (ClO4-) is a common groundwater constituent with both synthetic and natural sources. A potentially important source of ClO4- is past agricultural application of ClO4-3- fertilizer imported from the Atacama Desert, Chile, but evidence for this has been largely circumstantial. Bohlke and others (2009), reported perchlorate was present in all samples collected in the study, and some concentrations exceeded the New York drinking-water guidance level of 50 nmol/L (5 μg/L). The highest concentrations were from the areas where fireworks disposal and military activities were potential sources.
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Table of Contents
Below are other science projects associated with this project.
Long Island Water Availability
Long Island Precipitation
NWIS - the USGS Data Archive
Long Island Surface Water - Streamflow
Long Island Groundwater Levels
Long Island Water Table and Surface Maps
Long Island Water Use
Long Island Groundwater Budget
Long Island Inflow to the Groundwater System
Long Island Outflow from the Groundwater System
Long Island Water Suitability
Long Island Groundwater System Potential Hazards
- Overview
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.
Saltwater Occurrence and Intrusion in the Aquifers of Long Island, New York
Freshwater on the island discharges along most of the periphery of the island, which prevents saltwater from entering the aquifers. In western Long Island, however, saltwater wedges that are hydraulically connected to the sea are found in aquifers on the Atlantic Ocean side of the island. The saltwater wedge in the Lloyd aquifer extends seaward of the wedges in the overlying aquifers because of the relatively impermeable clays of the Raritan confining unit, and the high potentiometric head in the Lloyd Aquifer, which force freshwater in the Lloyd aquifer to extend seaward of the island (figure 29). The positions of the saltwater wedges have been attributed mainly to natural conditions that prevailed long before the start of groundwater development in western Long Island. Groundwater pumping, however, has caused a landward migration of the freshwater-saltwater interface in aquifers in western Long Island since the late 1890s (Lusczynski and Swarzenski, 1966; Buxton and Shernoff, 1999). Saline groundwater is also probably migrating downward into the Lloyd aquifer from the overlying Jameco and Magothy aquifers in areas of heavy pumping. In the Forks areas of eastern Long Island, saltwater underlies freshwater in lens-shaped reservoirs that resemble those that underlie outer areas of Cape Cod, Massachusetts (Nemickas and Koszalka, 1982).
Sources/Usage: Public Domain.Figure 29. Generalized cross section on Long Island with estimated salty groundwater areas (Barlow, 2003).(Public domain.) Recent investigations which focused on saltwater concerns within public supply system are presented in Stumm (2001) and Stumm & others (2002).
Pesticide Occurrence
Pesticide-Related Chemicals Detected in Long Island Groundwater 1996-2010
by USGS, SCDHS, and SCWA:Detailed water quality monitoring data, from monitoring conducted by Suffolk County and the U.S. Geological Survey, are available in a document titled “Water Quality Monitoring for Pesticides, Historical Monitoring Data for the Long Island Pesticide Pollution Prevention Strategy”. Datasets in that document indicate minimum, maximum and median concentration levels of pesticides and degradates detected from about 1997 to 2011.
Source: Link to Online Report
The U.S. Geological Survey (USGS) National Water Quality Assessment (NAWQA) program is designed to assess the status of the Nation's water quality, describe trends in water quality, and provide a sound scientific understanding of the primary natural and human factors that affect the quality of the Nation's water resources. One component of the NAWQA program is the study of pesticides to determine their occurrence, concentrations, and seasonal variability in surface and groundwater throughout the country. The study was conducted as part of the Long Island-New Jersey (LINJ) coastal drainages NAWQA project. The LINJ study area is one of 59 areas studied nationwide.
Source: Link to Online Report
The NAWQA Pesticide National Synthesis Project, which began in 1992, is a national-scale assessment of the occurrence and behavior of pesticides in streams and groundwater of the United States and the potential for pesticides to adversely affect drinking-water supplies or aquatic ecosystems.
Source: Nawqa report
Source: Nawqa fact sheet
Nitrogen Loading
Although nitrogen is abundant naturally in the environment, it is also introduced into aquifers through sewage and fertilizers. Chemical fertilizers or animal manure is commonly applied to crops to add nutrients. It may be difficult or expensive to retain on site all nitrogen brought on to farms for feed or fertilizer and generated by animal manure. Unless specialized structures have been built on the farms, heavy rains can generate runoff containing these materials into nearby streams and lakes. Wastewater-treatment facilities that do not specifically remove nitrogen can also lead to excess levels of nitrogen in surface or groundwater.
Several USGS investigations have evaluated the nitrogen loads and trends entering Long Island's surrounding estuaries from groundwater and surface water. Trends in nitrogen concentration and nitrogen loads entering the South Shore Estuary Reserve (Monti and Scorca, 2003) were evaluated on 13 major south-shore streams in Nassau and Suffolk Counties, Long Island, New York with adequate long-term (1971-1997) water-quality records. Furthermore, 192 south-shore wells with sufficient water-quality data, were selected for analysis of geographic, seasonal, and long-term trends in nitrogen concentration. An example of the long-term trend in one of the 13 streams is shown in figure 30.
Sources/Usage: Public Domain.Figure 30. Annual mean nitrogen load calculated for Bellmore Creek, Nassau County, N.Y. (Monti and Scorca, 2003)(Public domain.) Seasonal and long-term trends of nitrogen loads entering Long Island Sound from groundwater and streams on Long Island, New York were analyzed for four major streams on the north shore of Long Island that have long-term discharge and water-quality records for the period 1985-1996 (Scorca and Monti, 2001).
Volatile Organic Compounds
Volatile Organic Compounds (VOCs) "are organic compounds that can be isolated from the water phase of a sample by purging the water sample with inert gas, such as helium, and, subsequently, analyzed by gas chromatography. Many VOCs are human-made chemicals that are used and produced in the manufacture of paints, adhesives, petroleum products, pharmaceuticals, and refrigerants. They often are compounds of fuels, solvents, hydraulic fluids, paint thinners, and dry-cleaning agents commonly used in urban settings. VOC contamination of drinking water supplies is a human-health concern because many are toxic and are known or suspected human carcinogens — (U.S. Geological Survey, 2005).
Source: Nawqa Reports on VOCs analysis.
Pharmaceuticals Occurrence
In 2002, the U.S. Geological Survey (USGS), in cooperation with the Suffolk County Water Authority (SCWA), began a 4-year study to document the occurrence of pharmaceutically active compounds in groundwater wells throughout Suffolk County. Benotti and others (2006) collected seventy (70) water samples from 61 wells in the upper glacial and Magothy aquifers (9 wells were sampled twice) during 2002–2005 and analyzed for 24 pharmaceuticals. Wells were selected for their proximity to known wastewater-treatment facilities that discharge to the shallow upper glacial aquifer. Of the 70 samples taken, pharmaceuticals were detected in 28, of which 19 contained one compound, and 9 contained two or more compounds. The report summarizes the results from the study and relates the concentrations and frequencies of detection to those reported from a 1998–2000 nationwide study of streams that receive wastewater (Kolpin and others, 2002).
Perchlorate Occurrence
Perchlorate (ClO4-) is a common groundwater constituent with both synthetic and natural sources. A potentially important source of ClO4- is past agricultural application of ClO4-3- fertilizer imported from the Atacama Desert, Chile, but evidence for this has been largely circumstantial. Bohlke and others (2009), reported perchlorate was present in all samples collected in the study, and some concentrations exceeded the New York drinking-water guidance level of 50 nmol/L (5 μg/L). The highest concentrations were from the areas where fireworks disposal and military activities were potential sources.
_______________________________
Table of Contents
- Science
Below are other science projects associated with this project.
Long Island Water Availability
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...Long Island Precipitation
The National Oceanic and Atmospheric Administration (NOAA) National Climatic Data Center (NCDC) offers several types of climate information generated from examination of the data in the archives. These types of information include record temperatures, record precipitation and snowfall, climate extreme statistics, and other derived climate products. A collection of statistical weather and climate...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 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.