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For more than 100 years the U.S. Geological Survey (USGS) has provided
earth science information to help others understand and manage the Nation's
energy, land, mineral, biological, and water resources. Such information
is used in many decisions regarding management and optimum use of
Virginia's natural resources and to address major environmental, economic,
and health issues, such as contamination of the environment by hazardous
wastes, adequacy of suitable-quality water supplies, nutrient input to
streams and estuaries, distribution of coal and mineral resources, and
effects of urban development and agriculture on the environment.
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Virginia's hydrologic and geologic hazards have included floods, droughts,
and landslides. The USGS, in cooperation with the Federal Emergency
Management Agency, is currently conducting geologic mapping and evaluation
of landslides, debris-flows, and flood effects caused by flash flooding in
summer 1995 in the Blue Ridge Province of Madison County and other parts of
the Shenandoah Valley region (fig. 1).
Specific sites of future potential damage from debris flows and flooding
are being identified, as well as alternatives for mitigation of debris-flow
hazards.
(Click on image for a larger version, 83K JPEG)
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Figure 1. Flood effects in Shenandoah National Park in
summer 1995. | |
Much of the hydrologic data collected by the USGS is provided continuously
(real-time data) to resource managers, planners, and forecasters for
predicting and minimizing the impacts of natural hazards. These data are
obtained at hydrologic monitoring stations equipped with telephone lines or
satellite transmission equipment. The National Weather Service uses the
real-time data from USGS streamgaging stations to forecast streamflow
conditions on major rivers and smaller streams in densely populated areas.
Real-time hydrologic data also are used to minimize hazards caused by
low-flow or drought conditions. Numerous reservoirs in Virginia currently
are managed on the basis of real-time streamflow conditions to ensure
adequate water supply at municipal intakes and to maintain minimum
in-stream flows for preservation of fish and wildlife habitat.
As part of the U.S. National Seismograph Network, the USGS supports a
regional seismic network with a station at the Virginia Polytechnic
Institute and State University in Blacksburg. The national network, which
consists of more than 1,750 stations, is designed to provide rapid
notification of seismic events to emergency services personnel; a
consistent archive of standardized, high-quality, and nationwide seismicity
data; and a national data base for public information on earthquakes.
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In virtually all parts of Virginia, the quantity, quality, and distribution
of water are critical to the State's economy, public health and welfare,
and resource management. Public protection from floods and droughts,
multiple use of limited water resources, and effects of land and water use
on water quality are among the typical issues.
The USGS, in cooperation with other Federal, State, and local agencies,
operates and maintains long-term and continuous hydrologic data-collection
networks with the Virginia Department of Environmental Quality. The
statewide networks consist of monitoring sites at which surface- and,
ground-water and water-quality data are collected and recorded. The data
are collected and processed by using nationally standardized techniques and
special-purpose instrumentation, including satellite telemetry,
multiparameter water-quality sensors, global positioning systems, and
water-level sensors. The data, which are stored in computer files, are
available either through the Internet or annual publications. |
In Virginia, streamflow is recorded continuously at more than 160
streamgaging stations, and peak flows are monitored at more than 45
crest-stage sites (fig. 2). Streamflow data
are used extensively by the general public; industry; Federal, State, and
local agencies; and utility companies to make a wide variety of decisions,
including those regarding safe river-rafting conditions, selection of
future water supplies, flood control and warning systems, bridge and
culvert design, management and operation of reservoirs and hydroelectric
powerplants, and permits for water use and discharge of treated
wastewater.
(Click on image for a larger version, 66K JPEG)
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Figure 2. Measurement of surface-water flow from a cable
suspended above a stream. |
The ground-water data network in Virginia consists of more than 250 wells
at which water levels are measured at least twice each year. These data
are used to document natural changes in water levels in aquifers and to
monitor long-term water-level declines that result from pumpage.
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The availability of high-quality ground and surface waters for private,
municipal, industrial, and agricultural uses has been and will continue to
be of utmost importance within Virginia. Many USGS activities are directed
at hydrologic and geologic issues associated with water supply.
The USGS, in cooperation with the Virginia Department of Environmental
Quality, collects, compiles, and manages site-specific and aggregated
water-use estimates. The water-use information is published every 5 years.
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The USGS, in cooperation with the Virginia Department of Environmental
Quality and the Hampton Roads Planning District Commission, evaluates the
effects of ground-water pumpage on the availability of local and regional
water resources in the Coastal Plain of Virginia. The assessment is based
on a digital ground-water flow model that is integrated with spatial data
maintained in a geographic information system (GIS). The model and GIS are
used to help evaluate permit requests to withdraw ground water from the
Coastal Plain aquifers. The information is critical for maintaining a
sustainable supply of freshwater to meet the continuing population growth
and increased demands for freshwater.
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Information on the status, trends, and causes of water-quality conditions
in the State is vital to decisionmakers who set priorities, regulations,
and policies for the optimum management of water resources. Scientific
information about how, when, and where chemicals enter water supplies can
help managers tailor protection strategies. An understanding of human and
environmental influences on water quality is useful to identify quickly and
efficiently locations throughout the State that are most vulnerable to
contamination, to identify priority aquifers and streams that require
protection, and to devise appropriate and cost-effective
watershed-management strategies.
The Chesapeake Bay, which is one of the largest estuaries in the world and
home to more than 2,700 species of plants and animals, is a major economic
and recreational resource in Virginia. In 1987, the Governor of Virginia
signed the Chesapeake Bay Agreement, which commits Federal, State, and
other agencies to work toward improving the quality of water in the Bay and
to reduce controllable nutrient input to the Bay by 40 percent by
2000. |
USGS information is provided to managers and scientists to evaluate the
need for pollution-control practices, policies, and strategies in the
Chesapeake Bay watershed. The USGS has worked with the Virginia Department
of Environmental Quality since 1988 to determine the amounts of nutrients
and suspended solids that enter the Bay from five major tributaries in
Virginia and to assess whether water-quality conditions are changing over
time. In addition, the USGS has recently initiated a 5-year baywide
ecosystem assessment on ground-water/surface-water relations, living
resources, and topographic and geologic processes that affect water quality
in the Bay.
The ecosystem assessment will be coordinated with other relevant and
ongoing activities to document and further understand conditions in and
processes that affect the Bay watershed. One activity involves a USGS
study conducted with the Accomack-Northampton Planning District Commission,
which evaluates geohydrologic and chemical processes that affect
agricultural nonpoint-source contamination. These processes, which govern
how nitrate and other contaminants move in the ground water and ultimately
discharge to estuaries on the Eastern Shore, can be applied to many other
areas within the Chesapeake Bay region. An understanding of these
processes helps water-resource planners and managers, and the agricultural
community to develop effective crop-management practices to control
nonpoint-source contamination in ground water.
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The USGS is currently evaluating the quality of water in major aquifers of
the Coastal Plain that are used for water supply in the heavily urbanized
Hampton Roads area of Virginia. This effort is coordinated with the
Hampton Roads Planning District Commission and the Virginia Department of
Environmental Quality and includes an assessment of the spatial
distribution of saltwater and the rate of movement of saltwater into fresh
ground-water supplies. Geologists from the USGS and the Virginia
Department of Environmental Quality are currently assessing the role of a
giant meteorite impact, which occurred 35 million years ago in the
Chesapeake Bay region, on the location and extent of the salty water in the
freshwater aquifers.
The city of Newport News and the USGS are assessing the quality and
quantity of streams and associated reservoirs to optimize water-supply
strategies. Ongoing USGS efforts include analysis of organic material and
chemical constituents in selected reservoirs and associated watersheds and
assessment of factors, including hydrology, land use, wetland environments,
and seasonality, that affect distribution of the organic material.
The USGS, in cooperation with the Virginia Department of Conservation and
Recreation, Division of Natural Heritage, is evaluating hydrologic and
geochemical processes in protected wetlands in the North Landing River
Basin. Knowledge of the hydrologic interaction between agricultural
uplands and associated wetland ecosystems, as well as site-specific
hydrologic and geochemical processes that occur within the ecosystems, is
needed to manage this natural preserve effectively. |
The USGS is actively involved with addressing Virginia's concerns about
urban development and its effect on water quality. The USGS, in
cooperation with the Virginia Department of Transportation (VDOT), is
evaluating the effectiveness of stormwater-management facilities in
controlling increases in highway runoff and associated chemical
constituents caused by expanded highways. The USGS is also working with
the VDOT and the Virginia Polytechnic Institute and State University to
assess the hydrology and effectiveness of reconstructed wetlands in
Manassas. Benefits of natural stream restoration techniques, retention
ponds, and other best-management practices on stream-water quality in a
heavily urbanized area in Prince William County are being investigated by
the USGS, in cooperation with 15 local, State, and Federal agencies.
Migration of toxic contaminants at hazardous-waste sites is a continued
concern throughout Virginia. The USGS, in cooperation with the U.S.
Environmental Protection Agency, Virginia Department of Environmental
Quality, and various military branches of the U.S. Department of Defense,
is evaluating migration of toxic contaminants at hazardous-waste sites and
military installations in Virginia. Detailed descriptions of geohydrologic
settings, water quality, and rates and directions of ground-water and
contaminant flow are provided by the USGS. These descriptions help others
to evaluate and optimize potential remedial actions at hazardous-waste
sites.
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Since 1986, the USGS has conducted a nationwide assessment of water-quality
conditions in streams and ground water known as the National Water-Quality
Assessment (NAWQA) Program. Five major river or aquifer systems in
Virginia are studied in the NAWQA program. These systems are located in
the Potomac River Basin, the Albemarle-Pamlico drainage basin, the
Kanawha-New River Basin, the Upper Tennessee River Basin, and the Delmarva
Peninsula. The long-term goals of the NAWQA Program are to describe the
status and trends in the quality of surface- and ground-water resources and
to identify the natural and human factors that affect their quality.
Communication and coordination with local and State water-resource
officials are key components of the national program. |
The USGS is working with the National Park Service to protect and preserve
the natural and cultural resources within Shenandoah National Park.
Geologists are mapping surficial deposits and overburden, and hydrologists
are assessing quantity and quality of ground water and springs. The
geologic and hydrologic information is presented in general interest
publications and exhibits, and is useful to understand, preserve, and
manage the Park's natural ecosystem, as well as to provide adequate and
high-quality water supplies to 2 million visitors each year.
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The USGS Biological Resources Division (BRD, formerly the National
Biological Service) provides information on water quality, fisheries, acid
rain, and priority species in Virginia. Senior biologists provide
expertise and technical assistance in biological collections and
interpretation of data in three NAWQA study areas, including the Potomac
River basin, the Albemarle-Pamlico drainage basin, and the Upper Tennessee
River Basin. BRD biologists are also involved in studies on the passage of
fish, such as striped bass, through the Little Falls Dam on the Potomac
River, in collaboration with the U.S. Army Corps of Engineers, National
Park Service, the U.S. Fish and Wildlife Service, and State agencies. BRD
is also studying the effects of acid rain and habitat degradation in the
Appalachian region and, with the assistance of the Southern Appalachian Man
and the Biosphere Program, is developing a system for sharing this
information with local communities. |
The Virginia Cooperative Fish and Wildlife Research Unit is located on the
Virginia Polytechnic Institute and State University campus in Blacksburg.
Unit scientists conduct research throughout the State on fishery issues,
habitat modification, and endangered species in conjunction with State and
Federal agencies. Many of their efforts focus on freshwater mussel ecology
and restoration.
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The USGS Mineral Resource Data System (MRDS) is a digital data base of more
than 110,000 mineral sites worldwide and provides mineral-related
information to other Federal, State, and local agencies; industry; and the
general public. The MRDS contains information on about 1,400 sites in
Virginia that focuses mostly on occurrences of iron, gold, manganese,
copper, and sand and gravel. This information has been developed in
cooperation with the Virginia Department of Mines, Minerals, and Energy
(DMME), Division of Mineral Resources.
Scientists at the USGS are conducting geophysical studies, such as
aeromagnetic and aerial gamma-ray spectrometer surveys, that provide
important information for assessing mineral-resource potential. The
surveys provide data about the characteristics of rocks near the Earth's
surface and help distinguish rock units that are deeply weathered. These
data are useful for determining the geologic framework of a region and also
can be used to assess natural radiation hazards. Digital geophysical data
sets for Virginia are being compiled by the USGS, in cooperation with the
DMME, Division of Mineral Resources, and Mary Washington College.
The USGS is completing a quantitative national assessment of mineral
resources for five commonly used metalsÑgold, silver, copper, lead, and
zinc. The assessment lists and quantifies significant known deposits and
identifies areas with mineral potential. Tracts outlined in Virginia may
contain undiscovered deposits of copper, lead, and zinc and two types of
gold deposits. |
As part of its mineral-resource assessment program, the USGS, State
resource agencies, and universities are assessing the potential for
undiscovered industrial polymineralic resources offshore of the Atlantic
Coast (from Florida to Maine) on the basis of geological, geophysical, and
geochemical studies. Information in digital and paper form assists Federal
and State land-management agencies, regional planners, industry, and local
governments in ensuring adequate supplies and optimal management of these
important minerals.
The USGS, in cooperation with the DMME, Division of Mineral Resources, is
characterizing the quality of coal resources on public and private lands.
The information is useful to regulatory agencies, land-management agencies,
industrial interests, and academic researchers.
Acid mine drainage in Contrary Creek in Louisa County is being investigated
by the USGS, the U.S. Army Corps of Engineers, the National Park Service,
and the DMME, Division of Mineral Resources. Specifically, scientists from
the cooperating agencies are investigating relations between different iron
precipitates in neutral and acidic parts of the creek and water chemistry.
Such relations may help in the development of a cost-efficient tool to
assess accurately the acidity and water quality of other streams in
Virginia and throughout the Nation.
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State agencies currently cooperate with the USGS on digital topographic and
geologic data collection, as well as traditional map-revision activities.
For example, the USGS cooperates with and provides data to the DMME,
Division of Mineral Resources, which has recently completed the new
"Geologic Map of the State of Virginia." Geologic mapping is currently in
progress in the Piedmont and the Coastal Plain of southern Virginia, in
cooperation with the DMME, Division of Mineral Resources. These maps
provide information needed for construction of highways, bridges, and
industrial sites; evaluation of sites of environmental contamination; and
identification of sources of construction materials. Geologic mapping
completed in northern Virginia addresses multiple land-use and
environmental issues in areas of metropolitan growth. One of the Nation's
first radon-risk maps, which is based on the geologic mapping, was
completed recently for Fairfax County. Computer models developed by the
USGS that combine geologic, land-use, and environmental data are used by
Loudoun County to screen potential landfill sites. |
Geologic mapping also is conducted with National Cooperative Geologic
Program funds to increase the coal mine data base. This information can be
used for permitting and reclamation of coal mines, coal reserve and
coal-quality studies, and engineering studies related to subsidence and
underground mine development.
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Among the most popular and versatile products of the USGS are its
1:24,000-scale topographic maps (1 inch on the map represents 2,000 feet on
the ground). These maps depict basic natural and cultural features of the
landscape, such as lakes and streams, highways and railroads, boundaries,
and geographic names. Contour lines are used to depict the elevation and
shape of terrain. The maps are used extensively for civil engineering,
land-use planning, natural-resource monitoring, and other technical
applications. These maps have long been favorites with the general public
for outdoor recreation. The State of Virginia is covered by 815 maps at
this scale. Digital elevation models are available for about 99 percent of
the State. |
The National Mapping Program fosters partnerships with State and Federal
agencies to improve the effectiveness of its data-collection activities, to
maximize resource sharing, and to enhance the availability of timely and
accurate data to the general public. The USGS cooperates with the DMME,
Division of Mineral Resources, on the acquisition of statewide aerial
mapping photography through the National Aerial Photography Program.
Initial overflights were completed in spring 1994. These photographs are
used to revise maps and to produce digital orthophotoquads, which are
digitized aerial photographs with displacement caused by camera tilt and
terrain relief removed. Digital orthophotoquads combine the image
characteristics of a photograph with the geometric qualities of a map.
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Earth Science Information Centers (ESIC's) provide information about USGS
programs, products, and technological developments to the public. The ESIC
in Charlottesville was established under a cooperative agreement with the
DMME, Division of Mineral Resources. An ESIC also is located at the USGS
National Center in Reston. As part of a national ESIC network, these
offices provide information on cartography, geography, digital data, remote
sensing, geology, geophysics, geochemistry, hydrology, aerial photography,
and land use. |
Virginia is the home of the USGS Headquarters at the National Center in
Reston. The National Center supports almost 2,000 employees and
contractors who seek answers to many earth science questions that face the
Nation and who produce scientific reports, maps, and digital products. The
National Center also houses the USGS Visitors Center, where more than
10,000 people visit each year to learn about aerial photography, floods,
dinosaurs, volcanoes, earthquakes, water quality, and how USGS maps are
made. |
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