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A two‐component hydrograph separation for three high‐elevation catchments in the Sierra Nevada, California
Author(s) -
Huth A. K.,
Leydecker A.,
Sickman J. O.,
Bales R. C.
Publication year - 2004
Publication title -
hydrological processes
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.222
H-Index - 161
eISSN - 1099-1085
pISSN - 0885-6087
DOI - 10.1002/hyp.1414
Subject(s) - snowmelt , hydrograph , meltwater , hydrology (agriculture) , environmental science , snow , groundwater , watershed , surface runoff , geology , geomorphology , ecology , geotechnical engineering , biology , machine learning , computer science
Two‐component hydrograph separations were performed for three, nested, snowmelt‐dominated catchments in Sequoia National Park. The purpose of the hydrograph separations was to: (i) differentiate between the old and new water contributions to discharge during snowmelt using δ 18 O signatures; (ii) identify the fraction of snowmelt that travelled through the subsurface (reactive) compartment during the snowmelt period using silica or sodium; and (iii) investigate the impact of changing end‐member signatures on the separations. ‘Old’ water refers to water that was stored in the watershed during the previous year, whereas ‘new’ water is current snowmelt. Hydrograph separations were performed for both a high‐accumulation (1998, annual precipitation 2·4 m) and an average year (1999, 1·3 m). The proportion of old water contribution to discharge during the rising limb of the hydrograph was 10–20%, with 80–100% of snowmelt being reactive, i.e. passing through soil and talus. Estimates of old and new soil water and direct snowmelt entering the stream varied among the catchments in 1999. Differences between these components were minimal in 1998, regardless of varying topography and differing proportions of soil, rock and talus. Using time‐dependent rather than constant δ 18 O meltwater and silica soil‐water signatures made a meaningful impact on both new and old water, and reactive and unreactive, estimates. Copyright © 2004 John Wiley & Sons, Ltd.