Shenandoah
Task page
Geologic Framework of the Northern Shenandoah Valley Carbonate Aquifer System
The
northern
Shenandoah Valley of
Virginia and West
Virginia is
an area
of expanding population and economic development. To meet the water
resource
demands, the karst aquifer in the region must be developed. Local land-use managers are in need of
detailed geologic and hydrogeologic information to make informed
decisions of
source-water protection and land use related to subsidence. Information used for local studies will be
incorporated into a regional study that will help scientists better
understand
carbonate rock/ground water interactions and karst subsidence
development. The KARST project will provide
karst and
hydrogeologic information that
can ultimately be
used to guide land-use management and development as related to
ground-water
resources.
This
task will
complete geologic
mapping for the Winchester 30' X 60' quadrangle by
producing detailed
geologic maps
of the Shenandoah Valley part of the quadrangle and
lead to publication
of the Winchester sheet. The geologic maps
will be used, along
with fracture
analysis and karst inventories, to look at structural and stratigraphic
relations between karst features and geology.
Digital geologic maps will be produced at 1:24,000 scale. In the
final
year of the project (FY 2007), the Winchester 30' X 60' quadrangle will
be compiled from this
detailed
mapping and from previous mapping from Winchester project of the early and
mid 1990's.
The
approach to this task will be
geologic mapping that will be used to define
geologic formations and describe folds, faults, and joints to
investigate their
relationship to the carbonate aquifer and surface expression of
karst. Karst features will be accurately located by
field examination and be described in their
relationship to
the geology and hydrogeology to determine geologic controls on karst
development. The rock-fracture network
will be defined by measuring fractures (in terms of orientation,
persistence,
aperture, and intensity) and conduit system to better understand how
ground-water moves through the karst system.
Sinkhole distribution analyses will define areas for potential
entrance
points of contaminants and areas of potential subsidence hazards.
This
Task of the KARST Project works
in partnership with the
USGS Water
Resources Discipline, Virginia Water Science Center (George Harlow,
David Nelms) West
Virginia Water Science Center (Mark
Kozar)
This project
participates in the Great Valley
Water Resources Science Forum
Click here to
read fact sheet on the USGS integrated assessment of the Northen
Shenandoah Valley in Virginia and West Virginia (PDF file -- 129KB)
Map showing status of
USGS geologic mapping in the Shenandoah Valley of parts of
Virginia and West Virginia. Large gray rectangle is the Winchester 30'
X 60' quadrangle.
Click on links below for status
and availability of geologic maps:
Boyce
Hayfield
Inwood
Middletown
Middleway
Mountain Falls
Stephens City
Stephenson
Whitehall Winchester24K
Winchester100K
U.S. Department of the Interior | U.S. Geological Survey
