A study of enso-effect using long term unregulated southern hemespheric river flow records

El-Nino is piling up of warm pool of water usually present in western tropical pacific eastwards towards the coast of Peru.The warm pool will also increase in area and intensity.The related atmospheric activity is the southern oscillation .The southern oscillation and ist recognised interaction is now known as ENSO.The Phinomenon comprises of both a warm phase termed 'El-Nino'and a cold phase 'La-Nina'.In this article long term monthly river discharge data was analysed using wave let analysis . The energy associated with aperiodic phenomenon was illustrated . The scatter plots clearly point out the changes in the river flow in El_Nino ,La_Nina and normal years.River discharge data being an integrator at least in the basin scalebetter reflects the effct of a-periodic phinomina like El-Nino Some important applications of the study were pointed out.