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Temporal analysis of the frequency and duration of low and high streamflow: Years of record needed to characterize streamflow variability

S. Huh·D.A. Dickey·M. R. Meador·K.E. Ruhl
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Abstract

A temporal analysis of the number and duration of exceedences of high- and low-flow thresholds was conducted to determine the number of years required to detect a level shift using data from Virginia, North Carolina, and South Carolina. Two methods were used - ordinary least squares assuming a known error variance and generalized least squares without a known error variance. Using ordinary least squares, the mean number of years required to detect a one standard deviation level shift in measures of low-flow variability was 57.2 (28.6 on either side of the break), compared to 40.0 years for measures of high-flow variability. These means become 57.6 and 41.6 when generalized least squares is used. No significant relations between years and elevation or drainage area were detected (P>0.05). Cluster analysis did not suggest geographic patterns in years related to physiography or major hydrologic regions. Referring to the number of observations required to detect a one standard deviation shift as 'characterizing' the variability, it appears that at least 20 years of record on either side of a shift may be necessary to adequately characterize high-flow variability. A longer streamflow record (about 30 years on either side) may be required to characterize low-flow variability. ?? 2005 Elsevier B.V. All rights reserved.

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S. Huh, D.A. Dickey, M. R. Meador, K.E. Ruhl. 2005. Temporal analysis of the frequency and duration of low and high streamflow: Years of record needed to characterize streamflow variability. https://doi.org/10.1016/j.jhydrol.2004.12.008

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