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Hydrogeochemical cycling and chemical denudation in the Fort River Watershed, central Massachusetts: An appraisal of mass‐balance studies
Author(s) -
Yuretich Richard F.,
Batchelder Gail L.
Publication year - 1988
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/wr024i001p00105
Subject(s) - denudation , weathering , bedrock , hydrology (agriculture) , geology , surface runoff , groundwater , streams , watershed , dissolved silica , precipitation , streamflow , drainage basin , geochemistry , geomorphology , chemistry , ecology , computer network , computer science , dissolution , biology , tectonics , paleontology , machine learning , physics , geotechnical engineering , cartography , meteorology , geography
The Fort River watershed in central Massachusetts receives precipitation with a composition similar to that in Hubbard Brook (New Hampshire), yet the average stream water chemistry is substantially different, showing higher p H and TDS. This is largely a function of bedrock and surficial geology, and chemical differences among small streams within the Fort River watershed are apparently controlled by the composition and thickness of the prevailing surficial cover. The surficial deposits determine groundwater and surface water flow paths, thereby affecting the resultant contact time with mineral matter and the chemistry of the runoff. Despite the rural setting, over 95% of the annual sodium and chloride in the streams comes from road salt; after correcting for this factor, cation denudation rates are about equal to those at Hubbard Brook. However, silica removal is occurring at a rate more than 30% greater in the Fort River. When climatic conditions in Hubbard Brook and Fort River are normalized, weathering rates appear consistently higher in the Fort River, reflecting differences in weathering processes (i.e., cation exchange and silicate breakdown) and hydrogeology. Because of uncertainties in mechanisms of cation removal from watersheds, the silica denudation rate may be a better index of weathering intensity.