Water inundation hazard and micro level basin hydromorphological relationships: a geographical assessment

Abstract

This paper is to evaluate the relationships between basin hydromorphological factors and water inundation issue delineating five broad watersheds in a micro level study area, Moyna basin of West Bengal, India, using remote sensing and GIS techniques along with mapping and measurement of the hazard affected areas. It is observed that hydromorphological characteristics have systematic non-linear complex co-relationships with this hazard. Drainage frequency, drainage density, drainage texture, form factor, elongation ratio, ruggedness index, and mean slope proportionate with water inundation; and constant of channel maintenance, length of overland flow, shape factor, basin relief, relief ratio, and embankment density disproportionate with it. Some factors response not significantly. Besides, high rainfall and low depth of groundwater level of Moyna basin increases inundation problem. Bhuvan web data, based on Resourcesat 1 (LISS III), during 2005–2006, has been considered here as the primary value and Resourcesat 2 (LISS IV) image data during pre and post rainy seasons of 2012–2014 as observed value. There it is observed that in Moyna basin water inundation is a permanent hazard but its area changes with time. Finally, there a water inundation model has been formed to evaluate and to compare water inundation/waterlogging based on considering ranks. In result, it is found that the central Moyna watershed has maximum water inundation/waterlogging problem. Small scale basin area study sometimes shows difficulties and also distortions from the general.