Featured Project
Use of Dissolved Helium as an Environmental Water
Tracer
Richter, F., R. Whittier, and A.I. El-Kadi. Use of dissolved helium as an environmental water tracer, J. of Hydraulic Engineering, American Society of Civil Engineers, 134(5): 672-675.
This study
deals with the development, calibration, and testing of an automated
technology
for using helium as a water tracer in continuous real-time monitoring.
The
instrument combines a gas extraction system and a helium mass
spectrometer. The
technology was tested in laboratory pipe, open-water, and porous- media
experiments, and the results were used to test helium breakthrough
curves
against those for salinity expressed by electrical conductivity. The
instrument
promptly responds to concentration changes. In general, accurate
results were
obtained for first arrival times and peaks of solutes, as well as for
the
dispersive characteristics of the breakthrough curves. The accuracy of
the
elution curves needs some improvement due to limitations of the helium
extraction system. In addition, the developed method is sensitive to
the water
flow rate and nitrogen pressure used in extracting helium from the
solution.
These issues can be addressed through calibration. Potential
improvements are
possible through the use of more precise helium concentration
quantification
equipment and through enhancement of the extraction method. The success
of the
methodology makes helium an attractive tracer for use near drinking
water
sources, in environmentally sensitive areas such as wetlands and fish
farms,
and near recreational or other areas where esthetics are a concern.
Figure from the
paper by Richter et al. showing success of using helium as an
environmental tracer