Meander geometry characteristics as a response to hydraulic and lithologic control in the active floodplains of Lower Nagar basin

ABSTRACT

The present work aims to evaluate the controlling factor of meander geometry in the alluvial rivers. The assimilation of lithologic and hydraulic analysis of the meandering channels puts new insight to the understanding of the meander geometry. The study compares two highly contrasting meandering rivers of Nagar and Kulik in the Lower Nagar Basin, India. To assess the connection between the meandering nature with the hydraulic and lithologic factors, extensive field survey was made during the bank-full monsoon period. The principal component analysis between the hydraulic variables and meandering components suggests that the hydraulic factors of Nagar more effectively control the bend structure of the river, whereas the lithology of the Kulik river controls the meandering planforms. The meander patterns have shown significant transition flowing over different lithologies of grainsize combinations. The statistical prediction based on the hydraulic functions was used to predict the future possible changes in meandering planform. Moreover, the implication of the result was validated with the past century changes and thus can be suitable for the river management practices. In general, the meandering dimensions (in terms of λ, A_m and R_c) are found to be maximized when finer materials are prevalent and vice-versa.

KEYWORDS:

• Meander geometry
• hydraulic control
• Grainsize statistics
• soil grain phi scale (Φ)

Acknowledgements

The authors are grateful to the local people for their support during the field survey.

Disclosure statement

Authors state that they have no known conflict of interest financially or academically that would influence the research work.

CRediT authorship contribution statement

Pranay Paul: Data curation, Formal analysis, Investigation, Methodology, Visualization, Writing – original draft & Validation, Review & editing. Biswajit Das: Data curation & Investigation. Nanigopal Sarkar: Data curation, Formal analysis. Rumki Sarkar: Data Curation, Investigation, Conceptualization, Methodology, Resources, Supervision, Validation, Review & editing.

Additional information

Funding

The authors did not receive any financial support from any profit or non-profit organization to conduct the research work.