Fiber-optic distributed temperature sensing (FODTS) is an established technique for identifying locations and quantifying fluxes of groundwater inflows into rivers and streams. FODTS has the advantage of being able to provide very high spatio-temporal res olution of groundwater inflows relative to conventional methods such as differential stream flow gauging. However, in the traditional longitudinal configuration in which the FODTS cable is deployed along the stream bed, the method may not provide detail on hyporehic exchange.