One-dimensional hydrodynamic modeling of GLOF and impact on hydropower projects in Dhauliganga River using remote sensing and GIS applications

摘要

This study presents the one-dimensional hydrodynamic modeling for the Glacier Lake Outburst Flood (GLOF) simulation for the six hydroelectric (HE) power projects in Dhauliganga River of Alaknanda Basin. ArcGIS and HEC-GeoRAS extension is used for the whole river GIS database creation. Elevation values and cross-sections were taken from digital elevation models. The initial flow hydrographs were used as upstream boundary condition in MIKE11. The land use/land cover map and Manning's N values for roughness were prepared using LANDSAT TM and CARTOSAT-1 and verified by the field observation. Cross-sections were also modified after identifying the actual cross-sections width and depth. Subsequently, simulation has been carried out by using MIKE11 HD model at different sections of the river stretch. Calibration is done for the period of June 1, 2001, to May 31, 2002, and validated for the year of 2005 with about 95 % accuracy of observed data. In this study, results have been carried out by 100-year flood ordinates and considering the redistribution of lateral flow from five catchments of Alaknanda Basin. The GLOF peaks for the breach parameters are 1394.28, 1552.04 and 1898.04 m(3)/s for breach width 40, 60 and 80 m, respectively, just the downstream of the lake site. It is inferred from the study that the GLOF for 80 m breach width gives the peak flood of 1575 m(3)/s at the project site 1 for first scenario and 3500 m(3)/s at the site 6 for second scenario. The maximum simulated water levels and depth for the Central Water Commission gauging site at Joshimath are 1381.49 and 4.329 m, respectively, for 100-year-plus GLOF event. This information is critical for the project design discharge calculations.