Author(s): R. Reshma; Soumendra Nath Kuiry
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Keywords: No Keywords
Abstract: A river evolves in terms of its geometry, flow direction, and water quality based on various natural and human induced factors such as alluvial depositions, floods and other natural disasters, climate change, construction of hydraulic structures, unplanned urbanization, etc. Water quality restoration, waterbody rejuvenation, and flood damage reduction – all require a primary and precise knowledge of this morphodynamic evolution of the system. Morphodynamic evolution of the Adyar River of Chennai (Tamil Nadu, India) over the past three decades is analyzed in this study with the aid of Google Earth Engine (GEE), freely available Landsat satellite data, and a few assessment indices - Normalized Difference Vegetation Index, Modified Normalized Difference Water Index, and Enhanced Vegetation Index. The spatio-temporal evolution of the river and the corresponding variation in alluvial deposition are extracted. An elevated deposition of sediments is found towards the Adyar estuary, the location where the river joins the Bay of Bengal. Besides, a gradual deviation in the flow path is also observed, though the river center-line alignment is more or less unaltered. The excessive sediment deposition may be due to the haphazard encroachments, urbanization, and industrialization along the floodplains of the Adyar River since the early twentieth century. There is a high requirement for sediment removal and proper maintenance of the river channel to ensure better flow, low sedimentation, and hence reduced damages during future flood events. The morphological pattern evaluated in this study can be used in a long-term morphological numerical model study to regain the health of the Adyar River.
Year: 2022