Hamski, J. P., The Ohio State University, Columbus, USA, hamski.2@osu.edu
Azad Hossain, A. K., University of Mississippi, University, USA,
Hasan, K. ., Dhaka University, Dhaka, Bangladesh,
Alsdorf, D. E., The Ohio State University, Columbus, USA,
Hossain, F. ., Tennessee Technological University , Cookeville, USA,
Pavelsky, T. ., University of California Los Angeles, Los Angeles, USA,
Khan, A. S., Institute of Water Modelling, Bangladesh, Dhaka, Bangladesh,
Hoque, A. Z., Institute of Water Modelling, Dhaka, Bangladesh,

ESTIMATION OF HYDRAULIC PARAMETERS AND DISCHARGE OF THE GANGES AND BRAHMAPUTRA RIVERS FROM SHUTTLE RADAR TOPOGRAPHY MISSION DIGITAL ELEVATION MODELS

In this study, the potential of utilizing Shuttle Radar Topography Mission (SRTM) Digital Elevation Model (DEM) data to study the hydraulics of lowland, braided rivers of the Ganges-Brahmaputra basins was evaluated. Landsat 7 images at 30m resolution were first classified to identify the water body from braided land areas for the estimation of hydraulic parameters. Water surface elevations measured from the SRTM DEM was found to have standard deviations of 5.59 m and 5.77 m for the Ganges and Brahmaputra rivers, respectively. The minimum reach length required for a reasonable estimate of water surface slope was found to be 131 km for the Ganges and 137 km for the Brahmaputra river. The water surface slope was estimated from a linear fit to be 8.45 cm/km for both rivers. Channel width was computed at each classified Landsat pixel along a center line obtained by thresh-holding the Laplacian of an image containing the distance from each channel pixel to the nearest bank pixel. The hydraulic radius was then derived from the channel width, water surface elevation and in-situ bathymetry data. Using an estimate of Manning’s roughness coefficient n, the discharges for the braided rivers were derived and compared with measurements from calibrated rating curves during the low-flow (pre-monsoon) season of 2000.

Poster presentation

Presentation is given by student: Yes
Session #:006
Date: 03-03-2008
Time: 17:30 - 19:30