Nutrient and chloride concentrations from the additions were used to estimate the uptake length (Sw, in m), uptake velocity (vf, in m/s) and uptake rate (U, in mg m−2 s−1) of nutrients. Uptake metrics of NH4+–N, NO3−–N and PO4 3−–P were calculated based on the comparison between the curves of measured and predicted nutrient concentrations over time during the experiment; the latter estimated from chloride concentrations. The predicted concentrations represent a null hypothesis, i.e., that nutrients are conservative and their variation over time was due solely to hydrological factors (i.e., advection, dispersion and dilution). The predicted nutrient concentrations at different times (N(pred)t) during the experiment were calculated using the following equation