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Tracing hydrologic flow paths in a small forested watershed using variations in 87 Sr/ 86 Sr, [Ca]/[Sr], [Ba]/[Sr] and δ 18 O
Author(s) -
Hogan James F.,
Blum Joel D.
Publication year - 2003
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 - 10.1029/2002wr001856
Subject(s) - throughfall , hydrology (agriculture) , watershed , snowmelt , storm , hydrograph , isotopes of strontium , environmental science , geology , soil water , soil science , surface runoff , geomorphology , chemistry , strontium , snow , machine learning , biology , computer science , ecology , oceanography , geotechnical engineering , organic chemistry
Natural variations in 87 Sr/ 86 Sr, [Ca]/[Sr], [Ba]/[Sr], and δ 18 O were used to investigate changing hydrologic flow paths during storm events in an 11.8 ha first‐order watershed of the Hubbard Brook Experimental Forest. Throughfall, soil water, and stream water were sampled during several storm events and a single snowmelt event. Throughfall had 87 Sr/ 86 Sr, [Ca]/[Sr], and δ 18 O values that were distinct from other water types. Soil water was highly variable in composition but could be separated into three distinct elevation zones in the watershed with 87 Sr/ 86 Sr and [Ba]/[Sr] both increasing with elevation in the watershed. Changes in 87 Sr/ 86 Sr, [Ba]/[Sr], and δ 18 O of stream water during storm events yielded complementary information about watershed hydrologic flow paths. Traditional hydrograph separation using δ 18 O values indicated that new water was only a small component of storm flow (9–18%), whereas 87 Sr/ 86 Sr and [Ba]/[Sr] ratios indicated that shallow subsurface flow (soil water) contributed significantly to storm flow in amounts up to 40%, depending on soil moisture conditions.