Evaluation of an inexpensive, small diameter temperature logger for documenting ground water – river interactions.
Johnson, A.N., B.R. Boer, W.W. Woessner, J.A. Stanford, G.C. Poole,
S.A. Thomas, and S.J. O’Daniel. Ground Water Monitoring and
Remediation. 25(4): 68-74. 2005.
Increasing numbers of studies are recording detailed
temperature data for characterization of ground water–stream exchange.
We examined laboratory and field operation of a small-diameter,
stand-alone and inexpensive temperature logger capable of investigating
stream–ground water exchange. The Thermochron iButton is a
17.35-mm-diameter by 6-mm-thick instrument that costs <$10 when
ordered in quantity. Testing of the loggers in a controlled temperature
bath revealed a precision of ±0.4°C and an accuracy of ±0.5°C for a
group of 201. More than 500 loggers have been installed in channels and
in subchannel and floodplain ground water environments in two
gravel-bedded rivers in the western United States. Loggers were placed
as single devices and in vertical arrays in monitoring wells with
diameters of 10.16, 5.08, 2.54, and 1.9 cm. We determined that the
loggers have four principal advantages over more commonly used wired
and currently available stand-alone logging devices: (1) the wireless
nature does not require the instrument location to be associated with a
control-recording system; (2) the small size allows for installation in
small hand-driven or direct-push monitoring wells and thus intimate
contact of the instruments with the hydrologic environment; (3)
multiple loggers are easily suspended in a single fully perforated
monitoring well, allowing for the collection of high-resolution
temperature profile data; and (4) the low cost of the loggers allows
for the deployment of large numbers, thus improving spatial resolution
in shallow ground water floodplain scale studies.
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