Articles | Volume 15, issue 3
Hydrol. Earth Syst. Sci., 15, 989–997, 2011
https://doi.org/10.5194/hess-15-989-2011

Special issue: Catchment classification and PUB

Hydrol. Earth Syst. Sci., 15, 989–997, 2011
https://doi.org/10.5194/hess-15-989-2011

Research article 23 Mar 2011

Research article | 23 Mar 2011

Hydrologic similarity among catchments under variable flow conditions

S. Patil1 and M. Stieglitz1,2 S. Patil and M. Stieglitz
  • 1School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, GA, USA
  • 2School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA

Abstract. An assessment of regional similarity in catchment stream response is often needed for accurate predictions in ungauged catchments. However, it is not clear whether similarity among catchments is preserved at all flow conditions. We address this question through the analysis of flow duration curves for 25 gauged catchments located across four river basins in the northeast United States. The coefficient of variation of streamflow percentiles is used as a measure of variability among catchments across flow conditions. Results show that similarity in catchment stream response is dynamic and highly dependent on flow conditions. Specifically, within each of the four basins, the coefficient of variation is high at low flow percentiles and gradually reduces for higher flow percentiles. Analysis of the inter-annual variation in streamflow percentiles shows a similar reduction in variability from low flow to high flow percentiles. Greater similarity in streamflows is observed during the winter and spring (wet) seasons compared to the summer and fall (dry) seasons. Results suggest that the spatial variability in streamflow at low flows is primarily controlled by the dominance of high evaporative demand during the warm period. On the other hand, spatial variability at high flows during the cold period is controlled by the increased dominance of precipitation input over evapotranspiration. By evaluating variability over the entire range of streamflow percentiles, this work explores the nature of hydrologic similarity from a seasonal perspective.