Fiber Optics for Quantification of Surface Water Ground Water Interaction

Fiber-optic distributed temperature sensing (DTS) is emerging as a powerful tool for observation of hydrological and ecological processes over a wide range of spatial and temporal scales. Several studies published over the last year suggest a broad range of applications (e.g., Selker et al., 2006a, b, Westhoff et al., 2007, Lowry et al., 2007, Moffett et al., 2008). DTS uses standard fiber-optic communication cables and can report the temperature of each meter of cable for distances exceeding 10 kilometers as frequently as every 3 seconds. With careful calibration, long integration times (›1 hour), and short cables (‹4 kilometer), precision approaching 0.01ºC can be achieved at 1-meter spatial resolution. With the ability to precisely observe temperature at tens of thousands of locations, DTS holds potential for transformative observation of diverse processes throughout earth and ecological science. An emerging application is the identification of locations, quantities, and temperatures of groundwater upwelling into streams. In addition, the use of energy balance models allows for computation of the effective volume of hyporehic zone exchange. Examples from Luxembourg, Switzerland and Oregon will be presented.