We have
demonstrated on previous webpages that pumping ground water from a well
will change the local ground-water flow regime. We have also demonstrated
that a plume of dissolved contaminants in ground water can be flushed from
the soil pores. It is because of these phenomena that it is possible to
split a plume of dissolved ground-water contamination into two discrete
plumes. There is often a considerable advantage to splitting a plume (if
you can't wait to find out about the advantage of splitting a plume click
here "TREATISE - VAPOR
REMEDY FOR SEEPS OF CONTAMINATED GROUND WATER". Remember to use
the back button on your browser to return to this page or go to the Table
of Contents page to relocate yourself).
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This first figure depicts
a plan view presentation of an equipotential map during pumping conditions
superimposed upon a plume of ground-water contamination (blue-gray shading)
during non-pumping conditions. The coupling of these two conditions in this
first figure is a good representation of an early stage of recovery of contaminated
ground water. Just to the outside perimeter of the capture zone boundary,
the pumpage of ground water from the recovery well causes the clean, outer
ground-water flowpaths to be re-directed to flow into portions of the downgradient
extent of plume. After sufficient flushes with clean ground water to this
portion of the downgradient extent of plume, the dissolved contaminants
in the ground water will be exhausted from the soil pores or rock voids
in this area. Unless these contaminants are not very stable, they will be
transported downgradient by the ground-water flow. If these compounds are
unstable, they could possibly break down to some other compound.
In this second figure a cross-sectional representation of this first figure
is depicted.
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This figure not only
displays the equipotentials (black equipotential lines) during pumping conditions,
but also the non-pumping equipotentials along with the plume of dissolved
product contamination in the water table. This figure demonstrates that
the deeper, clean ground-water flowpaths are re-directed to flow into portions
of the downgradient extent of the plume. The dissolved contaminants in the
ground water will be exhausted from the soil pores or the rock voids given
sufficient flushes with clean ground water. |
