Open AccessTributary chloride loading into Lake Michigan
Author(s) -
Dugan Hilary A.,
Rock Linnea A.,
Kendall Anthony D.,
Mooney Robert J.
Publication year - 2023
Publication title -
limnology and oceanography letters
Language(s) - English
Resource type - Journals
ISSN - 2378-2242
DOI - 10.1002/lol2.10228
Subject(s) - tributary , watershed , salt lake , hydrology (agriculture) , environmental science , chloride , water quality , geography , geology , structural basin , ecology , chemistry , geomorphology , cartography , geotechnical engineering , organic chemistry , machine learning , computer science , biology
Anthropogenic salt sources have contributed to rising salinities in the Laurentian Great Lakes. In Lake Michigan, chloride concentrations have risen from ~ 1–2 mg L −1 in the 1800s to > 15 mg L −1 in 2020. The watersheds of the approximately 300 tributaries of Lake Michigan vary in size and represent a wide range of land use, from undeveloped forested watersheds to urbanized and agricultural areas. The spatial variability in both size and land cover among Lake Michigan's tributaries contributes to enormous variation in chloride concentrations and loads. We performed a spatial assessment of Lake Michigan tributaries to calculate total annual salt loading, infer future conditions based on current patterns, evaluate the use of synoptic sampling, and identify watershed characteristics that drive high chloride concentrations. We found that the tributary load to Lake Michigan is 1.08 Tg yr −1 of chloride, and that chloride concentrations in Lake Michigan will likely continue to slowly rise in the coming decades.