Sand quarrying activities in an alluvial reach of Damodar River, Eastern India: towards a geomorphic assessment

ABSTRACT

River is a system in which it always tries to make a balance between input and output. Any type of human intervention may affect the whole system and alluvial rivers give response to this interference through changes in its morphology. This concept has serious implications on the present study of Damodar River (Eastern India). Though the hydrology and morphology of Damodar river have been controlled by human activities over the last 50 years, large-scale excavation of river sand from the Damodar riverbed was initiated in the mid-1990s due to increasing urbanization and industrialization. Mainly, the alluvial reach of lower Damodar river is highly affected by uncontrolled sand excavation. To identify the status of sand mining and assess the geomorphic impacts due to indiscriminate and unscientific sand mining, we select Damodar river in between Sillaghat and Sadarghat of West Bengal. It has been estimated that 8, 35,000 ft³/ day (in peak season) of sand is extracted through 71 sand mining areas only from the 40.625 km channel between Sillaghat and Sadarghat. With the help of Geographic Information System (GIS) and field survey, we tried to identify the effects of this huge extraction of sand on this river, which we mapped through Arc GIS software. From the prepared maps, we have identified that Thalweg dynamics, riverbank erosion, instability of river bars; channel bifurcation and pool-riffle sequence change are the major geomorphic impacts of sand mining. Keeping the above concept in the backdrop, it is essential to have a process-based understanding as well as in-depth study of the river for the sustainable management of this threatened river.

KEYWORDS:

• Damodar river
• sand excavation
• river morphology
• Thalweg dynamics
• instability of river bars
• pool-riffle sequence

Acknowledgements

The Damodar Valley Corporation and Irrigation and Waterways Department, Government of West Bengal are thankfully acknowledged for providing relevant data for this study. Thanks are accorded to Dr Arijit Mazumder for his assistance during the preparation of maps. We are thankful to Arijit Paul, Samiran Dutta, Asraful Alam and Sourav Mukhopadhyay for their assistance during the field survey. Prof. James Ball (Editor-in-Chief, JRBM) and his associates, and two anonymous reviewers, are duly acknowledged for improving and bringing the manuscript to this stage. This paper forms a part of Prasanta Kumar Ghosh’s doctoral research.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The authors are sincerely grateful to Department of Geography, The University of Burdwan, India for providing the necessary supports to do this work.