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ABSTRACT:
Boris
Faybishenko of Berkeley Lab has developed an omni-depth fluxmeter
to provide direct field measurements of water and concentration
flux at different depths in the vadose zone. Conventional
methods to obtain this information require taking samples
for laboratory analysis or calculations, which may lead to
large inaccuracies. Other in situ fluxmeters are limited
to measurements in near-saturated soils or require a preliminary
calibration of probes.
The
Berkeley Lab vadose zone fluxmeter measurements are based
on establishing the same water pressure on a tensiometer placed
inside a controlled soil environment as that exerted naturally
on a monitoring tensiometer located in undisturbed soil. This
fluxmeter can fit into a borehole four inches in diameter
or larger and is accurate to within 10 percent, if water pressure
is above approximately - 0.7 bars.
An innovative arrangement for large boreholes consists of
two semi-sheltered fluxmeters, one facing upward and one downward,
monitoring tensiometers placed in undisturbed soil, and a
vacuum-operated data acquisition system.
The Berkeley Lab fluxmeter enables farmers to monitor water
flux and chemical concentrations in soil, which in turn allows
them to optimize irrigation and drainage schedules, as well
as adjust pesticide and fertilizer applications to minimize
groundwater contamination. The fluxmeter can also be used
in monitoring and managing remediation of contaminated soils,
and mine tailing and landfill operations.
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