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INNOVATIVE RESEARCH FOR A SUSTAINABLE FUTURE
Groundwater Flux Meter
FLUX METER ASSESSES THE EFFECTS OF GROUNDWATER, SURFACE
WATER, AND CONTAMINATED SEDIMENT INTERACTIONS ON ECOSYSTEMS
Research Value
Land use decisions made by
people affect the type and
amount of contaminants that
enter groundwater (GW) and
surface water (SW). The
interactions of contaminants with
GW and SW affect aquatic
ecosystems. Contaminants are
often transported and
transformed in these GW/SW
interactions. To diagnose the
effects of GW/SW interactions
on contaminants and ecosystems,
first the movement of water must
be measured.
Measuring the movement of
water and contaminants between
GW and SW presents its own set
of issues compared to measuring
surface water flow in a stream,
for example. Three major issues
in measuring the flow between
GW and SW are that the water is
flowing through and interacting
with sediments, flow can change
direction throughout the year,
and the rate of flow is typically
very slow.
The slow flow of water between
GW and SW is often referred to
as seepage, or in scientific terms,
advective flux. Though seepage
is relatively slow, over time it
can add a significant amount of
water and dissolved chemicals to
a lake or other SW ecosystem.
The slow flow presents a
challenge in getting reliable
measurements over short time
periods. With more accurate
measurement and an enhanced
understanding of GW discharge
into SW ecosystems, scientists
can generate better long-term
estimates of levels and chemical
changes of the contaminants in
sediments.
Another difficulty in measuring
GW/SW flow is that the flux of
contaminants entering sediments
via GW discharge may vary in
space and time. EPA research is
addressing these issues by 1)
developing methods that make
use of relatively inexpensive self-
contained, off-the-shelf devices
(Ford etal, 2012) and; 2)
developing better metering
devices that can achieve
continuous long-term remote
monitoring of flow or flux.
Research Details
This project was conducted to
develop a durable advective flux
meter capable of unattended long-
term remote monitoring of the
sediment-water interfacial flux.
To allow monitoring and control
over the internet, a remotely
controlled monitoring module was
developed as part of the system.
An associated aim of this
research was to develop an
instrument that will better
capture the time-dependent
variability in flow that is
commonly encountered in
GW/SW interactions in natural
systems. Due to the number of
changes that continuously occur,
such as seasonal flow
fluctuations and changing land
management practices, collection
U.S. Environmental Protection Agency
Office of Research and Development
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of continuous flow data over
longer periods of time provides
better data to differentiate the
relative effects of these varied
influences. Improvements in the
ability to differentiate between
natural and man-made variations
can lead to more sustainable
improvements to ecosystem
health.
If the difficulties in measuring
GW/SW flow can be overcome,
these data can be combined with
aquatic chemical measurements
to help decide on the most
effective strategies to make lakes
and streams safer and more
sustainable for humans and
wildlife.
Outcomes and Impacts
The flux meter was useful at a
wide variety of sites. The meter
was first tested in a turbulent
stream at Santo Domingo,
Nicaragua. Additional tests of
the meter were conducted in the
Grand Calumet River in Indiana
and Lake Hartwell in South
Carolina. The Grand Calumet is
a slow moving river with fine
texture organic rich sediment,
while Lake Hartwell is a deeper
water reservoir with sandy
sediment.
Based on results of these tests,
refinements were made and an
improved advective flux meter
design was deployed for an
extended period in its remotely
operated configuration at a
Superfund site at Ft. Devens,
MA. The long-term GW flux
data from this study was to help
pinpoint the source of sediment
contamination, leading to
selection of a more reliable and
sustainable remediation strategy.
Flux meter being used to measure
GW flow into SW at Red Cove, part of
the Ft. Devens Superfund Site
CONTACTS
Technical Inquiries:
Bob Lien, 513-569-7443. EPA/
ORD/NRMRL/LRPCD/SSMB
lien.bob@epa.gov
Robert Ford, 513-569-7501.
EPA/ORD/NRMRL/LRPCD/
SSMB ford.robert@epa.gov
Communications:
Roger Yeardley, 513-569-7548.
EPA/ORD/NRMRL/LRPCD
yeardley.roger@epa.gov
More Land Risk Management
Research on the Web:
www.epa.gov/nrmrl/lrpcd
REFERENCES
Ford, R.G., Yeardley, R.B., Lien, B.,
and Acree, S. 2012. Developing
Rapid and Cost-Effective Tools for
Assessing Groundwater Impacts on
Contaminated Sediments. U.S.
Environmental Protection Agency,
Cincinnati, OHEPA/600/F-12/533
Ford, R.G., Acree, S., Lien, B.,
Scheckel, K.G., Luxton, T., Ross,
R., Williams, A. G., and Clark, P.
2011. Delineating landfill leachate
discharge to an arsenic contaminated
waterway. Chemosphere,
85(9):1525-1537.
Lien, B.K. and C.G. Enfield. 2010.
Automated Long-Term Remote
Monitoring of Sediment-Water
Interfacial Flux. EPA/600/R-
10/110.
www.epa.gov/nrmrl/pubs/600rl0110
/600rl0110.html
Ford, R.G., Acree, S., Lien, B.,
Scheckel, K.G., Ross, R., Luxton,
T., and Clark, P. 2009. Devens 2008
Monitoring update, U.S.
Environmental Protection Agency,
Cincinnati, OH. EPA/600/R-09/064.
Lien, B. K. 2006. Development and
Demonstration of a Bidirectional
Advective Flux Meter for Sediment-
Water Interface. EPA Report, U.S.
Environmental Protection Agency,
Cincinnati, OH, EPA/600/R-06/122.
U.S. Environmental Protection Agency
Office of Research and Development
EPA/600/F-13/130
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