HYDROLOGICAL REAPPRAISAL FOR VISHNUGAD PIPALKOTI HYDRO-ELECTRIC PROJECT

Abstract

Hydropower is currently the world's largest renewable source of electricity, accounting for 6 % of worldwide energy. The main objective of the study is to revise the water availability, power potential and design flood aspects of Vishnugad Pipalkoti Hydro-electric project on river Alaknanda. The original report was prepared by M/S WAPCOS Ltd in year 2007. In present work, ten daily flow data of Joshimath and the Helong dam site for a period of 40 years (1971-1910) were used to determine the 90 % dependable year with the help of method of ranking. Restricted and Unrestricted power potential were estimated on the basis of 10 daily flow data and accordingly energy potential was calculated for 90 % dependable year for plant capacity of 444 MW. Design flood has been estimated using Hydro-meteorological and statistical approach (frequency analysis). Detailed physiographic analysis has been carried out to compute physiographic and geomorphological parameters using ASTER DEM and GIS. Sedimentation studies at Helong site have also been carried out to separate coarse, medium and fine sediment load on the basis . of sediment data available from September 2008 to May 2011. The water availability for 90 % dependable year (2000-2001) works out to be 4067.24 MCM and design flood works out to be 14191.8 m3/s (PMF). The power potential works out to be 1258.05 MU.