Characterizing cross-sectional morphology and channel inefficiency of lower Bhagirathi River, India, in post-Farakka barrage condition

Aznarul Islam () and Sanat Kumar Guchhait
Additional contact information
Aznarul Islam: Aliah University
Sanat Kumar Guchhait: The University of Burdwan

Natural Hazards: Journal of the International Society for the Prevention and Mitigation of Natural Hazards, 2020, vol. 103, issue 3, No 53, 3803-3836

Abstract: Abstract The present research based on 39 cross sections, historical maps, satellite images, and intensive field investigations intends to portray the changes in the cross-sectional morphology and channel efficiency of the lower Bhagirathi River (Katwa to Nabadwip) after the Farakka barrage was constructed over the Ganga River in 1975. The study reveals that majority of the cross sections have undergone significant changes in terms of higher width/depth ratio (1972:71.4 and 1984:85.1), higher channel form index (1972:28.06, 1984:33.44), and higher areal asymmetry (1972:0.244, 1984:0.287). Thus, discriminant analysis based on the principal component analysis Z-score of the derived indices shows a reversal of the quadrant reflecting a definite change in cross-sectional morphology in the post-Farakka barrage condition. Though the Reynolds number and specific stream power increased due to the increase in the lean period (January to May) discharges by the controlled hydrology, channel efficiency has decreased which is reflected through the higher Chezy roughness factor (1972:0.095 and 1984: 6.802) and increasing braiding index (1994:0.103, 2019:0.294). This is due to the emergence of the transport-limited condition triggered by the inadequate discharge compared to the huge sediment load contributed by Bhagirathi bank erosion and the Ajay–Mayurakshi system. Moreover, the role of erosion permitting sand and silt facies triggering higher channel oscillation along the left bank and presence of plug bar deposits coupled with the suspected attraction of subsurface fault are also noted on the relative stability and channel orientation of the middle part of the study reach.

Keywords: Channel form ratio; Channel asymmetry; Channel efficiency; SL index; Farakka barrage; Ajay–Mayurakshi system (search for similar items in EconPapers)
Date: 2020
References: View complete reference list from CitEc
Citations: View citations in EconPapers (2)

Downloads: (external link)
http://link.springer.com/10.1007/s11069-020-04156-9 Abstract (text/html)
Access to the full text of the articles in this series is restricted.

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:spr:nathaz:v:103:y:2020:i:3:d:10.1007_s11069-020-04156-9

Ordering information: This journal article can be ordered from
http://www.springer.com/economics/journal/11069

DOI: 10.1007/s11069-020-04156-9

Access Statistics for this article

Natural Hazards: Journal of the International Society for the Prevention and Mitigation of Natural Hazards is currently edited by Thomas Glade, Tad S. Murty and Vladimír Schenk

More articles in Natural Hazards: Journal of the International Society for the Prevention and Mitigation of Natural Hazards from Springer, International Society for the Prevention and Mitigation of Natural Hazards
Bibliographic data for series maintained by Sonal Shukla () and Springer Nature Abstracting and Indexing ().