Evaluation of an Inexpensive Small‐Diameter Temperature Logger for Documenting Ground Water–River Interactions

Abstract

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 was examined. 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.

The influence of in-stream structures on summer water temperatures via induced hyporheic exchange

“…Calibration improved the accuracy of the iButton data from 61.0uC as reported by the manufacturer (http://www.ibutton.com) to approximately 60.1uC ( fig. 3 of Johnson et al 2005 where Dh is the hydraulic head difference between the piezometer and the surface stream adjacent to the piezometer (m) and Dz is the difference in elevation between the piezometer screen and the streambed surface adjacent to the piezometer (m) ( Table 1).…”

Spatial patterns of hyporheic exchange and biogeochemical cycling around cross‐vane restoration structures: Implications for stream restoration design

“…Vertical temperature profiles (TPs) were constructed by embedding seven iButton temperature sensors and loggers (DS1922L, Maxim, Inc., 0.0625 C resolution, 0.5 C accuracy, 130 s response time) [Hubbart et al, 2005;Johnson et al, 2005] into 2.5 cm diameter steel rods at depths of 5, 10, 15, 20, 25, and 30 cm in the streambed and at 5 cm above the streambed. Silicone sealant was used to waterproof the sensors and insulate them from the rod.…”

Buffered, lagged, or cooled? Disentangling hyporheic influences on temperature cycles in stream channels

“…From these data, a correction factor (either positive or negative) was established for each logger and added to the field results recorded by that logger. More extensive calibration tests by Johnson et al [2005] showed that expected error in similarly calibrated temperature measurements among loggers was <0.25°C.…”