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Separating hydrological and geochemical influences on runoff acidification in spatially heterogeneous catchments
Author(s) -
Kirchner James W.,
Dillon Peter J.,
Lazerte Bruce D.
Publication year - 1993
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 - 10.1029/93wr02203
Subject(s) - surface runoff , drainage basin , hydrology (agriculture) , water quality , environmental science , acid rain , acid neutralizing capacity , linear relationship , soil science , chemistry , geology , acid deposition , soil water , ecology , geography , mathematics , statistics , cartography , geotechnical engineering , organic chemistry , biology
Geochemical reactions and hydrologic regime both affect runoff chemistry in many catchments. Each factor can obscure the effects of the other. This complicates efforts to interpret and predict catchments' geochemical and hydrological behavior. Here we present simple empirical techniques for separating effects of discharge fluctuations and effects of changes in acid anion concentrations in catchment monitoring data. We illustrate these techniques with data from central Ontario. Statistically subtracting acid anion effects reveals that important water quality variables (e.g., sum of base cations, acid neutralizing capacity, H + , Al i ) are simple functions of the logarithm of catchment discharge. Likewise, correcting for discharge effects reveals that these water quality variables are roughly linear functions of runoff acid anion concentrations. The linear functions linking acid anion concentrations to water quality can be reliably predicted from bulk catchment runoff chemistry. Therefore acid anions' effects on water quality can be reliably predicted, even if they are obscured by discharge fluctuations in catchment monitoring data.