Investigation of Appropriate Model Structures for Modelling Small Urban Catchments

Although the hydrologic modelling of small urban catchments has been practised for several decades, guidance on the development of models is still needed. This research evaluates and compares several modelling structures of small residential areas with and without low impact development implementation using distributed and lumped models. Hypothetical small areas were modelled to examine several grid based models with different grid sizes. The results were used to test the ability of uncalibrated models to predict runoff using three model configurations: 1) single catchment, 2) grid, and 3) homogenous areas, where every building, backyard, and street was modelled separately as a single catchment. The results of the models were compared and evaluated based on the total runoff volume, peak flow rate, and infiltration volume. The results of a real case study show that the grid model is an appropriate model structure for modelling small urban catchments.