Exploring drainage/relief-scape sub-units in Atreyee river basin of India and Bangladesh

Abstract

The prime objective of this study is to identify drainage and relief diversity models of the Atreyee river basin of India and Bangladesh for showing some relief and drainage sub units with unique characters. To achieve the goals, 20 associated morphometric parameters (e.g. drainage density, drainage frequency, relative relief, ruggedness number, slope, hydraulic gradient, dissection index etc.) have been used as spatial raster data layers. Weighted compositing method is applied for computing these models. Diversity models are classified for achieving the subcategories of the relief and drainage and each sub category possesses homogenous morphometric features. The high drainage diversity is found in the northern and middle western part especially along the Atreyee river and few patches of the alluvial tract. Although out of the total area only 8.98% area (1982.03 km2) falls under the very high diversity zone and in this area drainage density, frequency, texture etc. are also high. The high relief diversity zone (1.54%) displayed at the source and some middle western part of the basin. These models are also validated using some individual parameters using spatial correlation methods. High correlations significant at 95–99% level satisfy the sensitivity of Drainage and Relief diversity models.