Assessing the Influence of Zero‐Flow Threshold Choice for Characterising Intermittent Stream Hydrology

ABSTRACT Zero‐flow recordings in gauged streamflow data are critically important for intermittent stream research. Acknowledging the high uncertainty in zero‐flow recordings, many studies pick a small number as zero‐flow threshold, below which the flow is considered to be zero. The choice of zero‐flow threshold is often arbitrary or unjustified, which leads us to wonder: would selecting a slightly different threshold change analysis result significantly? Here, we used a simple sensitivity analysis to assess how the choice of zero‐flow threshold impacts the calculated values of relevant metrics to intermittent stream research. Results show that these metrics tended to be more sensitive to lower zero‐flow thresholds, suggesting that even choosing a slightly different threshold could lead to meaningfully different results from the management perspective. This study highlights the need for reasonable justification of the choice of zero‐flow threshold and concludes with potential ways to reduce uncertainty in zero‐flow measurement.