Mapping of Flood Plain And Flood Reach of Rapti River in India using Remote Sensing & GIS Techniques

Abstract

The Rapti River is one of the most dynamic river of Ganga Plain and is characterized by frequent bank
erosion resulting in the shifting of bank line. Today, river dynamics and hydrological behavior are strongly influenced by
human activities in both catchment and inland areas. Knowledge of recent and historical fluvial dynamics and related
structural and morphological changes on the land surface (e.g. Sedimentation, accumulation, movement of the river bed)
is a key factor in assessing the risk of flooding and vulnerability of human resources and structures. The
geomorphological approach for the study of sub-catchment of river Rapti in parts of Uttar Pradesh attains significance of
in view of dynamic changes in Rapti channel and activation of old channel and there water logging during rainy season
and consequent risk to the existing civil engineering projects. Satellite images are permanent pictorial records of the
terrain and remote sensing satellite have the ability to provide repetitative coverage of of the same area at a particular
interval of time. In this study satellite images of the underlying area of Rapti River make it possible to identify and
demarcate the fluvial features and the emergence of newer one switch active and old flood plains of Rapti River. The
emergence of new fluvial characteristics and the degradation of the earlier one is attributed to the channel separation or
otherwise successive channel migration caused by high discharge or floods. Lateral expansion, translation of meander
and cut-offs formation are responsible for altering the planform of the channel. As conclusion, it is shown that the
combined analysis of satellite data information will be very useful in the flood application domain, especially with respect
to risk assessment and vulnerability mapping.