AUTOMATED CHARACTERIZATION OF STREAMWATER SPECIFIC CONDUCTIVITY RESPONSE
TO STORMS
Abstract
Specific electrical conductivity (SC) is a basic, effective indicator of
water quality. The recent increase in SC data collected with
high-frequency sensors has created a strong need for algorithms that can
aid interpretation of these data. This study presents an algorithm that
finds and quantifies SC temporal patterns and applies that algorithm to
a data set from a forested catchment. During and after rain events, we
show three patterns that emerge in SC time series: a solute flush,
resulting in an initial increase in SC, followed by a dilution, followed
by the SC’s recovery toward pre-rain conditions. We compared these SC
patterns to precipitation amount and intensity, antecedent wetness, and
seasonality. Our results indicate that the magnitude of the flush was
driven primarily by precipitation intensity and total rainfall during a
storm, and secondarily by antecedent moisture conditions. The magnitude
of the dilution was driven mainly by precipitation amount. The rate of
SC recovery was driven by precipitation amount and was correlated with
the dilution. Overall, the algorithm successfully extracted event-driven
characteristics in the SC time series, allowing the development of
functional relationships with hydrologic drivers. Applying similar
methodologies to more catchments in the future will help identify
functional relationships at more sites and use these relationships to
identify catchments most sensitive to future precipitation changes.