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Riparian soil temperature modification of the relationship between flow and dissolved organic carbon concentration in a boreal stream
Author(s) -
Winterdahl Mattias,
Futter Martyn,
Köhler Stephan,
Laudon Hjalmar,
Seibert Jan,
Bishop Kevin
Publication year - 2011
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/2010wr010235
Subject(s) - riparian zone , dissolved organic carbon , environmental science , boreal , hydrology (agriculture) , antecedent moisture , soil carbon , discharge , precipitation , taiga , soil water , soil science , drainage basin , environmental chemistry , surface runoff , chemistry , geology , ecology , geography , geotechnical engineering , cartography , runoff curve number , habitat , meteorology , biology , paleontology
Discharge is often strongly correlated to the temporal variability of dissolved organic carbon concentrations ([DOC]) in watercourses. One recently proposed way to model this is the riparian flow‐concentration integration model (RIM) concept that accounts for the role of flow pathway control on [DOC] dynamics in streams. However, in boreal systems, there is also commonly a seasonal pattern, which cannot be explained by variability in discharge alone. The objectives with this study were to (1) demonstrate RIM as a tool for studying variability in stream water chemistry, (2) investigate factors related to stream water DOC variability, and (3) modify RIM to account for these factors. RIM was used with 14 years of daily discharge and almost 500 stream measurements of [DOC] from a forested boreal headwater stream. We used the calibrated RIM to account for discharge influences and then investigated variables that could be related to DOC variability (air and soil temperature, soil moisture, precipitation, antecedent flow and stream sulfate). Five alternative formulations of RIM, with temporally varying soil concentration profiles based on the variability in soil temperature and/or antecedent flow, were evaluated. The model where only the effects of riparian soil temperature on dynamics in DOC depth profiles were included performed best overall. This dynamic RIM improved the Nash‐Sutcliffe to 0.58 compared to 0.42 for the flow‐only formulation and reduced the median absolute error from 3.0 to 2.1 mg L −1 . This study demonstrates that RIM is a simple way of modeling stream DOC and exploring controls on stream water chemistry.