Long Island Water Table and Surface Maps

Science Center Objects

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 water levels are referenced to a common datum such as sea level, the data can be contoured to indicate the configuration and altitude of the water table (Winter and others, 1998).

In addition to various practical uses of a water-table map, such as estimating an approximate depth for a proposed well, the configuration of the water table provides an indication of the approximate direction of ground-water flow at any location on the water table. Lines drawn perpendicular to water-table contours usually indicate the direction of groundwater flow along the upper surface of the groundwater system (figures 21A-C). The water table is continually adjusting to changing recharge and discharge patterns. Therefore, to construct a water-table map, water-level measurements should ideally be made at approximately the same time, and the resulting map is representative only of that specific time. These are called "synoptic" water level measurements.

 

contour maps of water-table surface of Long Island
Figure 21. Using known altitudes of the water table at individual wells (A), contour maps of the water-table surface can be drawn (B), and directions of ground-water flow along the water table can be determined (C) because flow usually is approximately perpendicular to the contours. Groundwater moves along flow paths of varying lengths in transmitting water from areas of recharge to areas of discharge (Winter and others, 1998).(Public domain.)

 

Water levels in the upper glacial aquifer (water table), Magothy aquifer, and Lloyd aquifer on Long Island have previously been mapped in detail and are depicted in many reports. The first water-table map was compiled in 1903 by Burr and others (1904) for the New York State Water Power Control Commission and the New York State Conservation Department (Burr and others, 1904).

Other water-table maps for Long Island were compiled by Veatch and others (1906) for 1903; Spear (1912) for 1908; Suter (1937) for 1936; Jacob (1945) for 1943; Lusczynski and Johnson (1951) for 1951; Kimmel (1971) for 1970; Koszalka and Koch (1971) for 1971; Koszalka (1975) for 1974; Vaupel and others (1977) for 1943, 1959, 1966, and 1972; Nakao and Erlichman (1978) for 1975; Donaldson and Koszalka (1983) for 1979; Doriski (1986) for 1983; Doriski (1987) for 1984; Busciolano and others (1998) for 1997; Busciolano (2002) for 2000, and Monti and others (2009) for 2006.

The first potentiometric-surface map of the Magothy aquifer was compiled by Koch and Koszalka (1973) for 1972. Other Magothy aquifer maps were compiled by Prince (1976) for 1975; Vaupel and others (1977) for 1959, 1966, and 1972; Donaldson and Koszalka (1983) for 1979; Doriski (1986) for 1983; Doriski (1987) for 1984; Busciolano and others(1998) for 1997; Busciolano (2002) for 2000, and Monti and others (2009) for 2006.

The first potentiometric-surface map of the Lloyd aquifer was compiled by Lusczynski (1952) for 1947. Other Lloyd aquifer maps were compiled by Rich and others (1975) for 1975; Donaldson and Koszalka (1983) for 1979; Doriski (1986) for 1983; Doriski (1987) for 1984; Busciolano and others (1998) for 1997; and Monti and others (2009) for 2006.

The most recent (2010) representation of the potentiometric surfaces of the water table, Magothy and Lloyd aquifers included depth to water information (Monti and others, 2013). These two links are derived products of Monti and others (2013) as an interactive map interface:

Source: Potentiometric Surface 2010

Source: Depth to Water 2010

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Table of Contents

State of the Aquifer, Long Island, New York - Introduction

Location and Physical Setting

Freshwater

  1. Hydrolgeologic Units
  2. Fresh and Saltwater Relations/Interactions

State of the Aquifer System

  1. Precipitation
  2. NWIS - the USGS Data Archive 
  3. Surface Water - Streamflow
  4. Groundwater Levels
  5. Water Table and Surface Maps
  6. Water Use
  7. Groundwater Budget
  8. Inflow to the Groundwater System
  9. Outflow from the Groundwater System
  1. Case Studies

Interactive Content