『Abstract
The Alaknanda and Bhagirathi rivers flow through the Higher and
Lesser Himalayas and confluence at Devprayag, which represents
the origin of the Ganga (or Ganges) river. In the present study,
a vast number of temporal and spatial samples of the river waters
were collected and analyzed for major cations and anions. In addition,
more recent and time series water flow data have been obtained
and based on these inputs, a more refined dissolved flux rates
have been estimated. The Alaknanda and Bhagirathi rivers show
significant variations in chemical compositions during different
seasons. Carbonate rock weathering is responsible for more than
70% of the chemical compositions in the river waters. The chemical
weathering rates show seasonal variations and are much higher
during non-monsoon season. The dissolved flux of Alaknanda river
is much higher (1.80×106 tons yr-1) as compared
to the Bhagirathi river (0.34×106 tons yr-1).
The chemical weathering rates in the basin vary between 85 and
155 tons km-2 yr-1, which is significantly
higher compared to the global average of 〜24 tons km-2
yr-1.
Keywords: Chemical weathering; Alaknanda; Bhagirathi; Himalayan
rivers』
1. Introduction
2. Study area
3. Methodology
4. Results and discussion
4.1. Dissolved chemical composition
4.1.1. Major cations
4.1.2. Major anions
4.2. Dissolved flux and chemical weathering rates
5. Conclusions
Acknowledgements
References