Variation in Hydrologic Metrics
PCA analysis indicated the five flow metrics were highly variable across
the observed intermittency gradients (Figure 3). Because we were focused
on describing the broad patterns of variation between hydrologic metrics
and sites, we opted to primarily interpret the first two PCA axes (Table
3). The first PCA axis explained 47.97% of variation, and was
predominately driven by skew and pulse count, while the second PCA axis
explained 39.13% of variation, and was driven by reversals, number of
no-flow days, with some influence of reversals and the date of the first
no-flow day. Sites that fully dried were negatively associated with
reversals, pulse count and skew, and sites that dried to isolated pools
were more positively correlated with these metrics. Each site had a
relatively unique hydrologic signature, as evidenced by the variable
impact of each flow metric on the locations of sites within the PCA. The
relationships between drying regime (fully dry, drying to isolated
pools, or remaining flowing) and the variability of our selected
hydrologic metrics, underscores the variability of intermittent streams
at small spatial scales.