THERMAL REMOTE SENSING DETECTION OF GROUNDWATER DISCHARGE TO STREAMS

Assessment of spatially variable surface water–groundwater interaction has traditionally been limited; however, thermal remote sensing offers an opportunity for detecting both diffuse and focused groundwater discharge to streams. Stream temperature varies over a relatively large range on both diurnal and annual time scales when compared with groundwater, which maintains a more constant temperature year round. Because of this difference between groundwater and stream temperature, groundwater discharge has a measurable effect on the thermal regime of the stream that can be detected with airborne thermal remote sensing. Using this remotely-sensed stream temperature data and insitu stream temperature records, numerical modeling of the heat fluxes to/from the stream can be used to quantify the spatially variable rate of groundwater discharge. The use of this methodology can be made more cost effective and wide spread by employing unmanned aerial vehicles as an alternative to traditional helicopters.