Limits on the amount of water that can be pumped caps have been placed by New York State DEC in response to problems of saltwater incursion and the drying up of streams and lakes. Three sewer disposal districts handle MGD and this is discharged into surrounding saltwater bodies.
This compares to MGD of water that is pumped out of the system. The public supply wells are distributed evenly about the county. There are several water quality problems. The water is very acidic due to the low pH of rain. The water is neutralized by adding lime or caustic soda to prevent leaching of the pipes through which the water flows.
Another problem is nitrates. Six percent of the wells in Nassau exceed 10 mg per liter of nitrogen as nitrate that is the EPA minimum standard for drinking water.
Such wells are either abandoned or the water from the well is blended with that from a well that has a lower nitrate concentration. It is generally thought that the nitrate contamination resulted from septic systems used prior to the installation of the sewer system. Synthetic organic compounds from cleaning solvents, cesspool cleaners, etc.
Most of the contamination occurred prior to when testing first started because the contamination levels are remaining relatively constant. These organics in the water are treated by air stripping or passing the water over activated charcoal. High chloride concentrations for some wells are the result of salt water incursion or road salt. This problem is too expensive to treat. When high chloride concentrations appear in a well pumping is stopped. If the freshwater replaces the salty water in a well, pumping may be restarted.
The last problem is high iron concentration from natural iron within the aquifer system. Twenty-eight percent of the wells need to be treated to reduce the iron concentration to below 0.
This is done by filtering or chemically removing the iron. Suffolk County with an area of square miles covers a much larger area than Nassau County, but the population of 1. The recharge in the area is MGD. The total capacity of the aquifers underlying Suffolk County is about 70 trillion gallons. There are more than public supply wells in Suffolk County. Most of this water is returned to the aquifer with consumptive loss estimated to be 95 MGD.
The loss is through sewage systems, marine discharges and evapotranspiration associated with irrigation and lawn sprinkling. Most of Suffolk County is not sewered. Instead most homes have septic tank systems that discharge their waste water back to the groundwater system.
The most serious problem when using septic tanks is the introduction of nitrates into the ground water. When sewage is discharged to a septic tank or cess pool, some nitrogen is lost as ammonia or nitrogen gases and about half is oxidized to nitrate. EPA standards limit nitrogen as nitrate concentrations to less than 10 mg per liter.
If Suffolk County limits housing to one to two dwellings per acre, the nitrate standards should not be violated with the continued use of septic systems. Pathogenic bacteria in septic systems generally die off as the water passes through the zone of aeration and into the zone of saturation.
It is not clear that this is true for all viruses. As long as people do not dispose of organic compounds paint thinners, petroleum products, grease cutters, and other household chemicals through septic systems or pour it on the ground the water should not be contaminated by organic compounds. In areas where the density increases to greater than two dwellings per acre, sewering will be required.
The effluent from such systems could be discharged to the groundwater system and not to saltwater. While sewage systems can be built to produce effluent that meets drinking water standards, homeowner associations usually do not maintain such systems at a level to meet the standards. The precipitation, rain or snow, moves laterally in the Upper Glacial aquifer to streams and the shoreline or moves downward to the deeper Magothy and Lloyd aquifers.
The aquifer system reaches a depth of some 2, feet at Fire Island. The major zone for recharge, especially to the deeper aquifers, is along the center of the Island where the water table is highest. The Pine Barrens in Suffolk County, consisting of some , acres, are the last large nearly undeveloped area on Long Island.
Due to limited development and their location within the deep recharge areas, the groundwater in this area is particularly pure. 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 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 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. Below are several links to additional reports; these may not be referenced on this website. They are presented here for your convenience. The U. Geological Survey USGS , in cooperation with State and local agencies, systematically collects groundwater data at varying measurement frequencies to monitor the hydrologic conditions on Long Island, New York.
Each year during April and May, the USGS conducts a synoptic survey of water levels to define the spatial distribution of the The seaward-dipping sedimentary wedge that underlies the Northern Atlantic Coastal Plain forms a complex groundwater system. This major source of water provides for public and domestic supply and serves as a vital source of freshwater for industrial and agricultural uses throughout the region.
Population increases and land-use and climate changes NLCD provides spatial reference and descriptive data for characteristics of the land surface such as thematic class for example, urban, agriculture, and forest , percent impervious surface, and percent tree This total is slightly less than the estimate for , and about 5 percent less than total withdrawals in the peak year of Geological Survey USGS , in cooperation with State and local agencies, systematically collects ground-water data at varying measurement frequencies to monitor the hydrologic situation on Long Island, New York.
Each year during March and April, the USGS conducts a synoptic survey of hydrologic conditions to define the spatial distribution Perchlorate ClO4- is a common groundwater constituent with both synthetic and natural sources.
A potentially important source of ClO4- is past agricultural application of ClObearing natural NO3- fertilizer imported from the Atacama Desert, Chile, but evidence for this has been largely circumstantial. Here we report ClO4- stable isotope data Seventy 70 water samples were collected from 61 wells in the upper glacial and Magothy aquifers 9 wells were sampled twice during and analyzed for 24 pharmaceuticals.
Wells were selected for their proximity to known wastewater-treatment facilities that discharge to the shallow upper glacial aquifer. Pharmaceuticals were detected in Nineteen boreholes were drilled during The 13 major south-shore streams in Nassau and Suffolk Counties, Long Island, New York with adequate long-term water-quality records, and south-shore wells with sufficient water-quality data, were selected for analysis of geographic, seasonal, and long-term trends in nitrogen concentration.
Annual total nitrogen loads transported to The three main water-bearing units on Long Island, New York--the upper glacial aquifer water table and the underlying Magothy and Lloyd aquifers--are the sole source of water supply for more than 3 million people. Water-table and potentiometric-surface altitudes were contoured from water-level measurements made at observation, public-supply Manhasset Neck, a peninsula on the northern shore of Long Island, N.
Ground water at several public-supply wells has been affected by the intrusion of saltwater from the surrounding embayments Manhasset Bay, Long Island Sound, Hempstead Harbor. Real-time, daily, peak-flow, field measurements, and statistics of current and historical data that describe stream levels, streamflow discharge , reservoir and lake levels, surface-water quality, and rainfall in New York.
Surface-water data are collected and stored as either discrete field-water-level measurements or as continuous time-series data from automated recorders. Data from wells, springs, test holes, tunnels, drains, and excavations in New York; well location data includes information such as latitude and longitude, well depth, and aquifer.
Groundwater level data are collected and stored as either discrete field-water-level measurements or as continuous time-series data from automated recorders. Chemical, physical, and biological properties of water, sediment, and tissue samples from New York. Water-quality data are collected as either discrete field measurements or as continuous time-series data from automated recorders. Water Quality Watch provides access to real time water-quality data collected in surface waters throughout the United States as part of the USGS mission to describe water resources.
Measurements include streamflow through WaterWatch water temperature, specific conductance, pH, dissolved oxygen, turbidity, and nitrate. The animations are not a prediction of sea level rise, but rather illustrate areas of low elevation by a blue color simulating coverage by water. The numbers of people in those areas are tabulated. This mapper provides access to over 1. Each year during April and May, the USGS conducts a synoptic survey of water levels to define the spatial distribution of the water table and potentiometric surfaces within the three main water-bearing units underlying Long Island.
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