Advances in temperature tracer method of hyporheic exchange

The hyporheic zone, which is an important interface between the surface of the water and groundwater, is an active ecotone in a river ecosystem. The study on hyporheic zones and hyporheic exchange mechanism impose significant effects in assessing the development and utilization of water resources, and in maintaining and restoring the health of a river ecosystem. The present study systematically introduces the analytical model of a one-dimensional vertical steady-state and transient heat transport equation in the temperature tracer method, and combines and summarizes the research progress of temperature time-series data collection methods, signal analysis methods, and numerical methods, based on temperature tracing. Finally, the advantages and main problems of the temperature tracer method were compared and discussed, indicating that the uncertainty in temperature measurements, multi-dimensional groundwater flow, and impact of non-ideal conditions on these analytical models should still be emphasized in future studies on temperature tracer methods.