Numeric models of urban surface hydrology are useful tools to understand, develop and manage urban catchments to mitigate the rising economic cost of flooding due to urbanisation, changing precipitation patterns and sea level rise. Continuous distributed two dimensional (2D) Hydrological and Hydraulic (H&H) models, which estimate surface water flow depth and discharge at any point in the landscape rather than just the watershed outlet, increase the capacity of models to capture complex interactions within urban catchments through the inclusion of detailed geospatial information. However, computer resources may not be used efficiently if the spatial resolution required to resolve fine scale urban surface features is applied uniformly across the entire study area. This research describes and assesses a surface model that adapts its spatial resolution to the hydrological significance of the underlying area utilising the geomorphometric parameter flow direction whilst retaining a computationally simple and uniform data structure. The technique described combines geomorphometric hydrological analysis with hierarchical referencing systems and Level of Detail (LoD) modelling.