How and to what extent does the spatial and temporal discretization schema affect GIS-based hydrological modelling?

The justification of the spatial and temporal discretization schema is a critical step in the development of numerical hydrological models. Currently, the challenge remains in balancing the error and uncertainty induced by the algorithm and the mass calculation caused by the increase of the division of computational units. Thus, it is necessary to investigate an appropriate discretization scheme, which not only adequately represents the spatial heterogeneity characteristics, but also maintains a sufficiently high computational efficiency, with the constraints of the data validity and availability. This poster paper proposed a numerical hydrological model using different spatial and temporal discretization schema. Results show that the running time revealed an increase by an order of magnitude with the refinement of the grid size. The results also show that that the discretization schema impose various influences on different hydrological processes. For the infiltration process, the effect of the spatial and temporal resolution depend on the soil type; for the runoff process, the amount of the runoff was less affected but the time to runoff was significantly influenced. Establishing a standardized method to optimize the range of the spatial-temporal resolution for different the models and environmental scenarios, however, still remains challenge and is the future investigations.