Open AccessImpact of Dissolution of Saline‐Alkaline Soils on the Hydrochemistry and Erosion Rates of the Ganga River System
Author(s) -
Chatterjee Jayati,
Singh Sunil Kumar
Publication year - 2022
Publication title -
geochemistry, geophysics, geosystems
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.928
H-Index - 136
ISSN - 1525-2027
DOI - 10.1029/2021gc009914
Subject(s) - floodplain , hydrology (agriculture) , drainage basin , soil water , weathering , geology , tributary , silicate , erosion , soil salinity , alkali soil , environmental science , geochemistry , soil science , geomorphology , chemistry , ecology , geotechnical engineering , cartography , organic chemistry , geography , biology
We characterize here the saline‐alkaline soils composed of Na 2 CO 3 and NaHCO 3 in the Ganga floodplain and the peninsular basin using various chemical proxies and the isotopic composition of Sr. Abundance of saline‐alkaline soils in the Ganga floodplain and their higher solubility make them an important source of non‐chloride Na and other dissolved ions including Sr to the river waters. Inverse model based source apportionment of dissolved ions indicates ∼26%–71% of Na at the Ganga outflow is influenced by the saline‐alkaline soils; however, in some of the tributaries of the Ganga in the floodplain, for example, in the Gomti, this contribution exceeds 85%. The estimated silicate erosion rate by correcting for the saline‐alkaline soil contribution in the Ganga floodplain (∼5 tons km −2 yr −1 ) is less than one third of that of the Himalayan headwaters (16 tons km −2 yr −1 ) emphasizing the important role of physical erosion in controlling the chemical erosion in the mountain catchments compared to higher temperature and residence time in the floodplain. The silicate sourced dissolved fluxes from the floodplains are comparable to those from the Himalaya because of the vast drainage area of the floodplains and peninsular catchment. The findings of this study have direct relevance to studies on the determination of silicate weathering rates of not only the Ganga system, but also of other basins infested by saline‐alkaline soils such as the Columbia, the Colorado, the upper Rio Grande, the Missouri‐Mississippi river system, the Parana river, the Niger, the Nile, and the Orange.