Data were recorded until conductivity returned to ambient levels after passage of the solution pulse.
The time-curve conductivity data was used to calculate discharge (Q, L s−1) and average water velocity (v, ms−1) following Gordon et al. (1992). During this period, we simultaneously collected water samples with 30-mL plastic bottles at the bottom of the reach every 10–60 s following the frequency of conductivity changes over time.Water samples were filtered in situ through pre-ashed fiberglass filters (Whatman® GF/F) and placed in a cooler for transportation to the laboratory, where they were kept in the refrigerator until analysis. Chemical analyses were done within a week of the field experiment.