Abstract: To meet the requirements of current stormwater management practices, a model focusing on effective impervious surface and its influence on urban hydrological processes should be developed. Therefore, a model structure was developed based on model complexity, data availability, and prediction capability. The highly heterogeneous urban surface was discretized into subcatchments with uniform or "quasi-uniform" characteristics. Different hydrological calculation methods were used to develop a model that can explicitly distinguish the water generation and concentration processes of effective and non-effective impervious surfaces by considering the flow paths within and between subcatchments of different surfaces. This refined stormwater model can provide technical support for urban flood control and sponge city construction.