The area bound by the rivers Sabarmati and Luni forming a part of Nort
h Gujarat and Southwest Rajasthan alluvial plains has preserved in its
sediments and landscape various changes which have occurred in the dr
ainage systems during the Upper Quaternary times. The present day drai
nage mainly cuts across the material deposited by a set of older river
s which now stand disrupted. The present day rivers are observed to ha
ve been superimposed over older river channels and dominantly follow n
umerous tectonic lineaments and faults of a later date. The new channe
ls reveal and have preserved relicts of the earlier fluvial system. Ge
omorphic and drainage studies reveal existence of two ancient major ri
ver systems, the remnants of which are now represented by the Banas an
d Rupen rivers. The Banas, along with its major tributary Sipu is the
sole survivor of the older fluvial system, whereas Rupen has been part
ially destroyed.