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WATER RESOURCES RESEARCH, VOL. 41, W05007, doi:10.1029/2004WR003649, 2005

How snowpack heterogeneity affects diurnal streamflow timing

Jessica D. Lundquist

Scripps Institution of Oceanography, La Jolla, California, USA


Michael D. Dettinger

U.S. Geological Survey, La Jolla, California, USA


Abstract

Diurnal cycles of streamflow in snow-fed rivers can be used to infer the average time a water parcel spends in transit from the top of the snowpack to a stream gauge in the river channel. This travel time, which is measured as the difference between the hour of peak snowmelt in the afternoon and the hour of maximum discharge each day, ranges from a few hours to almost a full day later. Travel times increase with longer percolation times through deeper snowpacks, and prior studies of small basins have related the timing of a stream's diurnal peak to the amount of snow stored in a basin. However, in many larger basins the time of peak flow is nearly constant during the first half of the melt season, with little or no variation between years. This apparent self-organization at larger scales can be reproduced by employing heterogeneous observations of snow depths and melt rates in a model that couples porous medium flow through an evolving snowpack with free surface flow in a channel.

Received 15 September 2004; accepted 4 February 2005; published 6 May 2005.

Keywords: snow; streamflow timing; stream velocity; heterogeneity; diurnal cycle; Sierra Nevada.

Index Terms: 1839 Hydrology: Hydrologic scaling; 0740 Cryosphere: Snowmelt; 1860 Hydrology: Streamflow; 1847 Hydrology: Modeling; 4475 Nonlinear Geophysics: Scaling: spatial and temporal (1872, 3270, 4277).


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Citation: Lundquist, J. D., and M. D. Dettinger (2005), How snowpack heterogeneity affects diurnal streamflow timing, Water Resour. Res., 41, W05007, doi:10.1029/2004WR003649.