Combining experimental and modelling approaches to monitor the transport of an artificial tracer through the hyporheic zone

In order to advance methodologies used in the investigation of Hyporheic Zone (HZ) mixing processes, this article combines experimental and modelling tools follow a tracer injected into river infiltrating HZ. A highly concentrated sodium chloride solution was river; (i) conductivity, (ii) riverbed resistivity by Electrical Resistivity Tomography (ERT) (iii) vertically distributed concentrations within HZ were monitored. Both ERT concentration measurements showed an infiltration depth 35 cm, partial recovery after injection, which faster superficial layer that found be more resistive according initial image. The approach HydroGeoSphere code model coupling between surface flows groundwater transport processes. set-up involved 50 cm high existing step, vertical contrast saturated hydraulic conductivity aquifer discharge flux. Fitting profile, adjusted values 5 × 10−2 m s−1 for first permeable below riverbed, 4 10−6 bottom at least 10 times lower than value layer. Numerical simulations two main parameters controlling sediment riverbed. step less significant here compared these parameters. combination allowed us quantify flux, is complicated investigate field without any model. Results study combining with sampling allows quantification factors hyporheic exchange.