Evaluating Flow Metric-Based Stream Classification Systems to Support the Determination of Ecological Flows in North Carolina

Streamflow is a main determinant of the ecological health of rivers and streams. Assignment of streams to classes is suggested as an initial step in the process of establishing ecological flow standards that ensure the appropriate environmental objectives are achieved. A new article in the Journal of the American Water Resources Association evaluated a hydrological model with two distinct hydroecological river classification systems of stream classes in North Carolina and found that stream classification was inconsistent between all three models and highly dependent on the period of record of the underlying data. Based on these results, it was surmised that classification systems based on streamflow metrics are not a reliable approach for guiding ecological flow determinations.