USGS Groundwater Information: Branch of Geophysics
by Frederick Day-Lewis and John W. Lane, Jr.
U.S. Geological Survey, Office of Ground Water, Branch of Geophysics
Recent advances in fiber-optic distributed temperature sensor technology (FO-DTS) allow for thermal monitoring of hydrologic processes at higher spatial and temporal resolution than previously possible. Commercially available FO-DTS systems are capable of thermal resolution of 0.1 degrees Celsius and spatial resolution of 1 meter at sampling intervals of about 1 minute. Sensor cables, consisting of standard or armored telecommunications optical fibers, can extend for several kilometers under streams, lakes, or estuaries, or be used in boreholes. In 2006, the US Geological Survey (USGS) undertook a FO-DTS technology demonstration/evaluation in which FO-DTS surveys were conducted in support of six ongoing studies of ground-water/surface-water interaction and fractured-rock hydrology. Study objectives include mapping submarine ground-water discharge and identification of gaining stream reaches. For each project, additional hydrologic, chemical, or geophysical data were used to provide context for interpretation of the FO-DTS data. Here, we review several case studies and discuss lessons learned, with a focus on insights for efficient and effective deployment of FO-DTS systems in fluvial, lacustrine, and estuarine settings.
Final copy as submitted to Connecticut Conference on Natural Resources for publication as: Day-Lewis, F.D., and Lane, J.W., Jr., 2007, Using fiber-optic distributed temperature sensors for hydrology [abs.]: Connecticut Conference on Natural Resources, Storrs, Connecticut, March 9, 2007.
For further information, contact:
U.S. Geological Survey
Branch of Geophysics
11 Sherman Place
Storrs, Connecticut 06269