NON-LINEAR RAINFALL RUNOFF MODEL

Abstract

A lumped, time-invariant model based on systems approach has been used here for calibration and forecasting (verification) of flows during the flood events. The model used in the present study has in it a non-linear component and a linear component. In the rainfall-runoff process the immediate or prompt flow is expected to be non-linearly related with the rainfall while the delayed flow is expected to be linearly related with the corresponding rainfall. Such relationship is used for multi-flood events and by stacking together the different discontinues storms. The response functions for these systems are identified. The present model in its non-parametric form has been calibrated first and then used for forecasting the flood events from two non-seasonal catchments. One of them is the Bird Creek catchment which is located near Spery, Oklahorma •(U.S.A). It lies in a climatically semi-arid region. Another the Ray catchment is located near Swindon, England and it lies in a moderately humid climatic region. The response functions obtained for these two catchments are found to have physically realistic ordinates. The present method has been found to forecast the flows with high efficiencies for the data used herein.