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Simulation of freshwater-saltwater interfaces in the Brooklyn-Queens aquifer system, Long Island, New York

Water-Resources Investigations Report 98-4067

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Abstract

The seaward limit of the fresh ground-water system underlying Kings and Queens Counties on Long Island, N.Y., is at the freshwater-saltwater transition zone. This zone has been conceptualized in transient-state, three-dimensional models of the aquifer system as a sharp interface between freshwater and saltwater, and represented as a stationary, zero lateral-flow boundary. In this study, a pair of two-dimensional, four-layer ground-water flow models representing a generalized vertical section in Kings County and one in adjacent Queens County were developed to evaluate the validity of the boundary condition used in three-dimensional models of the aquifer system. The two-dimensional simulations used a model code that can simulate the movement of a sharp interface in response to transient stress. Sensitivity of interface movement to four factors was analyzed; these were (1) the method of simulating vertical leakage between freshwater and saltwater; (2) recharge at the normal rate, at 50-percent of the normal rate, and at zero for a prolonged (3-year) period; (3) high, medium, and low pumping rates; and (4) pumping from a hypothetical cluster of wells at two locations. Results indicate that the response of the interfaces to the magnitude and duration of pumping and the location of the hypothetical wells is probably sufficiently slow that the interfaces in three-dimensional models can reasonably be approximated as stationary, zero-lateral- flow boundaries.

Additional Publication Details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
Simulation of freshwater-saltwater interfaces in the Brooklyn-Queens aquifer system, Long Island, New York
Series title:
Water-Resources Investigations Report
Series number:
98-4067
Edition:
-
Year Published:
1999
Language:
ENGLISH
Publisher:
U.S. Geological Survey ; Branch of Information Services [distributor],
Description:
iv, 26 p. :ill., maps ;28 cm.