Tracing Bank Storage and Hyporheic Exchange Dynamics Using ²²² Rn: Virtual and Field Tests and Comparison With Other Tracers

Abstract Dynamic hydrologic exchange flows in river beds and banks are important for many ecosystem functions throughout corridors. Here we test whether the exchanges associated mixing between a flooding groundwater within river’s bank can be effectively traced by Radon‐222 ( 222 Rn), naturally occurring, inert, radiogenic, radioactive gas that analyzed monitored situ. The assessment was done simulation of flow reactive transport Rn following single, relatively rapid (hours long) flood wave auxiliary field observations Rn, temperature total dissolved solids (a surrogate any ionic conservative tracer). Results illustrate is more effective than tracing dynamic hyporheic exchange. variations space time larger analytical uncertainty common measurement methods. individual effects aquifer hydraulic conductivity, dispersivity, water concentration, topography were through sensitivity analysis. Larger conductivity lower concentration relative to groundwater, gentler slopes resulted prominent traceable signal. residence exchanged may estimated interpreted using models such as those implemented here. However, application sensitive fluctuations requiring it well characterized. provides guidance tracer surface interactions settings.