Application of Grey System Theory in the Development of a Runoff Prediction Model

The mathematical models used for modelling hydrological processes generally require relatively long-time data series. For developing countries like India, one of the major problems is unavailability of reliable hydrological data for longer durations. An attempt has been made in present study to model the rainfall-runoff process by using grey system theory, a relatively new approach in the field of hydrology. Grey system theory advances an approach to investigate the relationship of an input-output process with unclear inner relationships, uncertain mechanisms and insufficient information. Sixteen storm events for Kothuwatari watershed of Tilaiya dam catchment, Jharkhand, India, collected for the years 1993-1997 have been used for development and prediction of differential hydrological grey models. A least-squares method has been employed for the estimation of model parameters. Performance of the developed model has been evaluated through the qualitative and quantitative statistical indices. Lower values of various error indices and higher values of correlation indices confirm the ability of the model to predict storm runoff with reasonable accuracy for the study area.