Pattern of solute movement from snow into an upper Michigan stream

Canadian Journal of Fisheries and Aquatic Sciences
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Abstract

Precipitation, snowpack, snowmelt, and streamwater samples were collected in a small gauged watershed draining into Lake Superior during winter 1987–88 to assess the importance of snowmelt pattern and meltwater pathways in the occurrence of solute pulses in streamwater. The snowpack along the south shore of Lake Superior can contain 50% of annual precipitation inputs and 38% of annual ionic inputs including moderate levels of strong acids. Throughout winter, thawed surface soils and small but steady snowpack moisture release promoted movement of snowpack solutes to surface mineral soils. Preferential elution of K+, NH4+, and H+ from the snowpack occurred with the initial thaw. Most ions exhibited pulses in snowmelt. Transport of snowpack solutes to the stream during snowmelt was through near-surface soil macropores and overland flow. For those ions with concentrations higher in the snowpack than in the premelt streamwater, K+, NH4+, and H+, the earliest snowmelt pulses had the greatest influence on streamwater chemistry. Unlike other portions of the region with resistant bedrock, the widespread presence of alkaline glacial till provides excess stream acid neutralization capacity (ANC) to buffer acidic inputs. Peak winter streamwater ANC reduction was caused principally by spring melt dilution of base cations and associated alkalinity, constant high SO42- levels, and an increase in NO3-. The maximum reduction in stream ANC was concurrent with overland flow. Relative to its snowmelt concentration, NO3- was highest in streamwater with some stream input likely the result of nitrification and N mineralization.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Pattern of solute movement from snow into an upper Michigan stream
Series title Canadian Journal of Fisheries and Aquatic Sciences
DOI 10.1139/f90-031
Volume 47
Issue 2
Year Published 1990
Language English
Publisher National Research Council of Canada
Publisher location Ottawa
Description 11 p.
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Canadian Journal of Fisheries and Aquatic Sciences
First page 290
Last page 300