Identification of palaeochannel configuration in the Saraswati River basin in parts of Haryana and Rajasthan, India, through digital remote sensing and GIS

Abstract

The fluvio-aeolian sediments in the alluvial plains of NW Haryana and adjoining northern Rajasthan are known to conceal a number of palaeochannels of the erstwhile Saraswati River and its tributaries, which were also the sites for many pre-historic settlements dating back to the pre-Harappan era. Using digital remote sensing techniques like image enhancement, principal component analysis and mineral composite index mapping from Landsat ETM+ data, and hydrological routing and stream network generation from DEM, this work attempts to identify and map the palaeochannel networks roughly between Tohana, Hisar, Bhadra and Kalibangan along the north-eastern fringe of the Thar Desert, encompassing parts of Haryana and Rajasthan states, and links the outputs with field data. Based on the analysis, three major palaeochannels of the Saraswati river system, referred to as the northern, central and southern palaeochannels, have been identified. Their occurrence below the surface sand cover is roughly at a depth of 6-13 m. Based on the available dates on sediments in the locality, it has been concluded that the channels were last active between 6 and 3 Ka B.P., when they supported the archaeological settlements along their banks.