3-Low Flow Estimation in the Krishna River Basin, India

Abstract

The main objective of the study was to assess the surface water availability in the Krishna river basin during past years. Monthly discharge data at 17 selected gauging sites in the Krishna basin were considered for the period 1972-1995. The long period discharge data for the period 1901-1995 were available for the site at Vijayawada and the same was used in the analysis. Monthly and seasonal mean discharge values for various sites were estimated to study the temporal and spatial changes in the water availability. Year to year variations were considered to see the existence of any trend in the data series. A series of minimum monthly discharge data per year was constructed for each site. These series were then fitted with 2 parameter Weibull distribution. Parameters of the distribution were estimated by least square method. Using the inverse transformation of the cumulative distribution function and estimated parameters of the distribution, 80 % reliable monthly surface flow was estimated for each site. This measure was used as the indicator of water availability at different sites in the Krishna river basin.