CALIBRATION STRATEGY FOR URBAN CATCHMENT PARAMETERS

A simple and methodical strategy is presented for estimating the parameters of a catchment. The method makes use of rainfall-runoff records to construct response surfaces of the peak flow in terms of eight calibration parameters. The eight calibration parameters are assumed to vary between certain physically meaningful limits and to be random and uniformly distributed between the limits. Experimental design techniques and the response surface methodology are used here. The response surfaces are fitted within the limits. Optimal values on the response surfaces that match the observed peak flows are then obtained using a probabilistic algorithm. The values obtained are optimal since at that point on the response surface the probability density is the highest. The average of the optimal sets obtained for various rainfall-runoff records is an estimate of the catchment parameters. The estimated values are then verified on other storm runoff. The results obtained matched very well with the observed peak flow values.