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D. B. Sapik

Publications and source records attributed to D. B. Sapik.

4 recordsLinked to original sources
USGS1988

Documentation of a steady-state saltwater-intrusion model for three-dimensional ground-water flow, and user's guide

A finite-difference model that simulates three-dimensional flow of groundwater was modified to simulate steady flow of freshwater in a multiple-aquifer system containing freshwater and static saltwater. The two fluids are assumed to be immiscible, with constant but different densities, and are separated by a sharp interface. The interface position computed by the model for a test problem was in good agreement with the analytic solution for this problem. The model was developed to simulate seawater intrusion in coastal aquifers, but it could be used to simulate flow in any aquifer system that is bounded by saltwater. This report describes modifications made to the existing numerical model and the method of locating an interface , and contains a user 's guide for the model. (USGS)

Open-File Report↗
USGS1988

Ground-water resources and simulation of flow in aquifers containing freshwater and seawater, Island County, Washington

Aquifers in Island County, Washington, that are intruded by seawater from Puget Sound contain chloride concentrations that exceed 100 mg/L. Chloride concentrations exceeded 100 mg/L in 24 % of the wells that were drilled below sea level and sampled in August 1981, but most of the chloride concentrations did not exceed 1,000 mg/L. Groundwater occurs in glacial deposits that have a maximum thickness of 3,000 ft; the deposits were divided into five aquifers and five confining units. Four overlapping digital models were calibrated, using time-averaged data, to simulate three-dimensional steady flow of fresh groundwater in multiple aquifers containing freshwater and seawater separated by a sharp interface. Model simulations indicate that most of the recharge is discharged from aquifers C and D as springs below sea levels, and only a small fraction of the recharge moves downward below aquifer C. Simulations also indicate that aquifers beneath the islands are not recharged by groundwater that moves from the mainland through aquifers beneath Puget Sound except in the area of northeast Camano Island. Between Whidbey and Camano Islands, the freshwater-seawater interface intersects the bottom of Puget Sound and prevents movement of fresh groundwater between the two islands. (USGS)

Water-Resources Investigations Report↗
USGS1982

Preliminary survey of ground-water resources for Island County, Washington

Increased ground-water withdrawals associated with the population increase in Island County have caused concern about ground-water availability and potential seawater intrusion. The most widespread and widely used aquifer lies near sea level. Locally, available data also indicate that one or more water-bearing zones lie above the sea-level aquifer. Pumpage in 1979 totaled about 1.67 billion gallons; about 90% was pumped from the sea-level aquifer. Most large producing wells in the county have pumping water levels near or below sea level, so that if pumping continued for a long enough time, seawater intrusion would result. Sampling of chloride concentrations in July 1978, April 1980, and August 1980 indicated problem areas mainly in northeastern and southern Camano Island and in central Whidbey Island. (USGS)

Open-File Report↗