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

January 1, 2005

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.

Publication Year 2005
Title Temporal analysis of the frequency and duration of low and high streamflow: Years of record needed to characterize streamflow variability
DOI 10.1016/j.jhydrol.2004.12.008
Authors S. Huh, D.A. Dickey, M. R. Meador, K.E. Ruhl
Publication Type Article
Publication Subtype Journal Article
Series Title Journal of Hydrology
Index ID 70029662
Record Source USGS Publications Warehouse