Study On Physical Watershed Hydrological Model Based On Triangulated Irregular Network

The principles in the physically based hydrological models, which originated from the blueprint propounded by Freeze and Harlan, are rigorous conservation laws of mass and momentum, and the parameters of the models are clearly defined. Also, remote sensing technology provides more and more observing data for physically based models. Physically based models are promising for predictions in ungauged basins. However, current models are built on the grid based discretization method and cannot account for land surface heterogeneity and computation efficiency simultaneously.This dissertation proposes a quasi-physically based hydrological model based on represented slope-based discretization unit. The model includes a special seepage model for karst regions and can incorporate human activities. The model is applied to Qin River basin for a long term simulation with good results declaring the mechanism of water resources formation and interaction.To physically represent hydrological processes and balance the computation precision and efficiency, it is necessary to develop a physically based watershed hydrological model based on irregular network. After discussion on the applicability of different discretization approaches and the corresponding numerical methods, the author derive the discretization format of physical partial differential equations which describe the corresponding hydrological processes using finite volume method. A general mathematical framework for physically based hydrological model based on universal irregular network is proposed. The author also apply the general framework to develop the TIN based hydrological model.The TIN based model is applied to the upper reaches of Qin River basin. The calibration, validation and uncertainty evaluation results show the model can represent heterogeneity efficiently and physically describe the hydrological processes. The model can simulate and forecast the stream flow soundly.