• Southern Appalachians;
  • streamflow variability;
  • Pacific North American pattern;
  • wavelet analysis


We have examined streamflow variability in the Southern Appalachian region of the United States for the period 1950–2009. In particular, we have analysed the monthly discharge time series at two stations along the following rivers in North Carolina: (1) Little Tennessee River (LTR) near Prentiss and (2) French Broad River in Asheville. These two gauging stations are part of the Hydro-Climatic Data Network (HCDN) system. The HCDN system was developed by the United States Geological Survey (USGS) to provide a long-term database for tracking changes in flow and water quality of streams and rivers, with minimal human interventions. Using continuous wavelet transform (CWT), we have identified the dominant oscillatory modes in the monthly discharge data at these two rivers, and delineated the time intervals over which these modes may persist. It is found that in addition to the annual hydrologic cycle, the monthly discharge fluctuates at interannual timescales. These interannual variations may be linked to the Pacific North American (PNA) teleconnection pattern. Knowledge of the interannual periodicities may be useful for understanding long-term streamflow variability in the Southern Appalachian region. Understanding patterns of streamflow variability may be important for water resources management operations in the surrounding area. Copyright © 2010 John Wiley & Sons, Ltd.