Research Article

How isotopic fractionation of snowmelt affects hydrograph separation†

  1. Susan Taylor1,2,*,
  2. Xiahong Feng2,
  3. Mark Williams3,
  4. James McNamara4

Article first published online: 11 DEC 2002

DOI: 10.1002/hyp.1232

Issue

Hydrological Processes

Hydrological Processes

Special Issue: Eastern Snow Conference/Western Snow Conference

Volume 16, Issue 18, pages 3683–3690, 30 December 2002

Additional Information

How to Cite

Taylor, S., Feng, X., Williams, M. and McNamara, J. (2002), How isotopic fractionation of snowmelt affects hydrograph separation. Hydrological Processes, 16: 3683–3690. doi: 10.1002/hyp.1232

Author Information

  1. 1

    US Army Cold Regions Research and Engineering Laboratory, Hanover, NH 03755, USA

  2. 2

    Department of Earth Sciences, Dartmouth College, Hanover, NH 03755, USA

  3. 3

    Department of Geography and Institute of Arctic and Alpine Research, University of Colorado, Denver, CO 80217, USA

  4. 4

    Department of Geosciences, Boise State University, Boise, ID 83725, USA

*US Army Cold Regions Research and Engineering Laboratory, Hanover, NH 03755, USA.

  1. †

    This article is a US Government work and is in the public domain in the USA.

Publication History

  1. Issue published online: 11 DEC 2002
  2. Article first published online: 11 DEC 2002
  3. Manuscript Accepted: 16 SEP 2002
  4. Manuscript Received: 30 APR 2002

Funded by

  • Department of the Army
  • National Science Foundation. Grant Numbers: ATM-9628759, EAR-9903281, EAR-9526875, DEB-9810218, OPP-9814984
  • Army Research Office. Grant Numbers: DAAH04-96-1-0033, DAAH04-96-0289, DAAH04-00-1-0367
  • Water and Environmental Research Center, University of Alaska Fairbanks

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Keywords:

  • snowmelt;
  • 18O;
  • new water component;
  • hydrograph separation;
  • error analysis

Abstract

We present the isotopic composition of meltwater samples from four seasonal snowpacks: a warm, maritime snowpack in California; a temperate continental snowpack in Vermont; a cold continental snowpack in Colorado; and an Arctic snowpack in Alaska. Despite the very different climate conditions the δ18O of meltwater from all four snowpacks increased as melting progressed. This trend is consistent with theoretical results that model isotopic exchange between water and ice as meltwater percolates through a snowpack.

We have estimated the systematic error in the hydrograph separation if the isotopic composition of a snow core were used in place of that of meltwater. Assuming no error in the old water or stream water values, the error in the new water fraction depends on: (1) the isotopic difference between the snow core and the old water; (2) the isotopic difference between the snow core and the meltwater; and (3) the new water fraction contributing to the stream flow during a spring melt event. The error is large when snowmelt contributes a dominant fraction of the stream flow, which may be expected where infiltration of snowmelt is limited (e.g. permafrost, urban areas). A particular challenge will be how to incorporate the changes in isotopic composition of meltwater measured at a point into hydrograph separation models conducted at the watershed scale. Published in 2002 by John Wiley & Sons, Ltd.

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