Is Water availability over estimated ?
The availability of water in Narmada river has been assessed in the most sophisticated and systematic manner in consultation with the Central Water Commission (CWC), the highest expert technical body of the nation by utilizing rainfall series from 1891 to 1992 and actual river flow series from 1948 to 1992. The actual river flow series for 45 years is not adequate for planning mega-project with a life of more than 100 years and a large catchments with co-efficient of annual flow variations of 0.35 which may need minimum 130 years data of both rainfall and river flows. Therefore combined actual and hind cast available data of about 100 years is used as per international standard practice. Based on this method, 75% dependable availability is 27.22 MAF and not 22.69 MAF estimated by the critics. Even the World Bank in its detailed scrutiny while extending financial assistance had accepted and endorsed these calculations.
