U.S.
GEOLOGICAL SURVEY
Water-Resources Investigations Report 01-4252
Simulation of Ground-Water Flow and Potential Contaminant Transport at Area 6 Landfill, Naval Air Station Whidbey Island, Island County, Washington
Prepared
in cooperation with
DEPARTMENT OF THE NAVY
ENGINEERING FIELD ACTIVITY NORTHWEST
NAVAL FACILITIES ENGINEERING COMMAND
By F. William Simonds
ABSTRACT
A
three-dimensional finite-difference
steady-state ground-water flow model was
developed to simulate hydraulic conditions at the
Area 6 Landfill, Naval Air Station Whidbey
Island, near Oak Harbor, Washington.
Remediation efforts were started in 1995 in an
attempt to contain trichloroethene and other
contaminants in the ground water. The model was
developed as a tool to test the effectiveness of the
pump-and-treat remediation efforts as well as
alternative remediation strategies. The model
utilized stratigraphic data from approximately
76 Navy and 19 private wells to define the
geometry of the shallow, intermediate, and deep
aquifers and the intervening confining layers.
Initial aquifer parameters and recharge
estimates from aquifer tests and published
remedial investigation reports were used in the
model and then adjusted until simulated water
levels closely matched observed water-level data
collected prior to the onset of remediation in 1995.
The calibrated model was then modified to depict
the remedial pump-and-treat system, in which
contaminated ground water is extracted, treated,
and returned to the ground surface for infiltration.
The water levels simulated by the modified model
were compared with observed water levels for
the 1998 calendar year, during which time the
pump-and-treat system was in nearly continuous
operation and the ground-water system had
equilibrated to steady-state conditions. Although
artificial boundaries were used in the model, the
choice of model boundary conditions was
simulation in the area of primary concern
surrounding the western contaminant plume and
extraction wells. Particle tracking results indicate
that the model can effectively simulate the
advective transport of contaminants from the
source area to the pumping wells and thus be used
to test alternative remedial pumping strategies.
CONTENTS
Abstract
Introduction
Hydrogeology of the Ground-Water Flow System
Steady-State Simulation of the Ground-Water Flow System
Steady-State Simulation of Post-Remediation Conditions
Discussion of Ground-Water Flow Simulation
Summary and Conclusions
References Cited
This report is available online in Portable Document Format (PDF). If you do not have the Adobe Acrobat PDF Reader, it is available for free download from Adobe Systems Incorporated.
Download the report (PDF, 1.8 MB)
Document Accessibility: Adobe Systems Incorporated has information about PDFs and the visually impaired. This information provides tools to help make PDF files accessible. These tools convert Adobe PDF documents into HTML or ASCII text, which then can be read by a number of common screen-reading programs that synthesize text as audible speech. In addition, an accessible version of Acrobat Reader 5.0 for Windows (English only), which contains support for screen readers, is available. These tools and the accessible reader may be obtained free from Adobe at Adobe Access.
Send questions or comments about this report to the author, Bill Simonds (wsimonds@usgs.gov) 253.428.3600 ext. 2669.
For more information about USGS activities in Washington, visit the USGS Washington District home page.
