GIS and remotely sensed data-based morphometric elements analysis for determination of Bengal Basin evolution

In the current study, hypsometric integral (HI) using polynomial fitting, morphometric parameters (MP) and tectonic elements (TE) like iso-base map, stream length-gradient index, hydraulic gradient and sinuosity index were determined to understand the basin evolution. For this analysis, the study area was divided into four sections; (1) Area 1 (34,492 km²) covering the stable platform (2) Area 2 (48,137 km²) covering basin part (3) Area 3 (37,301 km²) also covering basin part (4) Area 4 (18,219 km²) covering the hilly area. Arc hydro tool and CalHypso extension were used with the ArcGIS for HI calculations. Streams of eighth order for Area 1 and Area 4, tenth order for Area 2, ninth order for Area 3 were identified from 30 m × 30 m shuttle radar topographic mission (SRTM) digital elevation model (DEM). Sixth-order watershed for the four regions were used for HI calculation. Principal component analysis was carried out on the morphometric parameters, but there is no significant correlation among MP; although few parameters show strong, moderate and good correlation. To achieve HI values, watersheds were selected randomly- 25 nos. out of 59, 64 nos. out of 118, 36 nos. out of 74 and 22 nos. out of 31 for the four areas, respectively. Area 1 possesses 92% mature and 8% young watersheds, Areas 2 and 4 possess 43% and 55% old, 54% and 40% mature, and 3% and 5% young watersheds, respectively. But Area 3 possesses 25% old and 75% mature watersheds. Based on HI, MP and TE it can be concluded that the study area is almost stable and passing through a quite state and no tectonic activity exists in this area. This information would facilitate to the planner, engineer and decision taker to develop this zone for infrastructure development regarding the venture.