Post-blackening approach for modeling dependent annual streamflows

The post-blackening (PB) approach is introduced for modeling annual streamf lows that exhibit significant dependence. This is a hybrid approach that bl ends a simple low-order, linear parametric model with the moving block resa mpling scheme. Empirical simulations performed using known hypothetical non linear parametric models, show that the hybrid model gains significantly by utilizing the merits of both the parametric model and the moving block res ampling scheme (nonparametric). Following this, the performance of the PB m odel is tested with four annual streamflow records with complex dependence, drawn from different parts of the world. The results from these examples s how that the PB approach exhibits a better performance in terms of preserva tion of summary statistics, dependence structure, marginal distribution, an d drought characteristics of historical streamflows, compared to low-order linear parametric models and model based resampling schemes (nonparametric model). Furthermore, it offers flexibility to the modeler and is also simpl e to implement on a personal computer. This hybrid approach seems to offer considerable scope for improvement in hydrologic time series modeling and i ts applications to water resources planning. (C) 2000 Elsevier Science B.V. All rights reserved.