The importance of spatially heterogeneous erosivity and the cumulative area distribution within a basin evolution model

Topography reflects the terrain composition and the forces to which it is exposed. The elements that control this shape are intuitive: precipitation, wind, soil composition, geologic activity, lithology, and vegetation. Each of these elements varies naturally in space. A model of basin evolution is shown to produce quantitatively different topography for different relative magnitudes of diffusive and incisive erosion processes. Spatial heterogeneities in erosivity also influence the simulated topography. The calibration of this evolution model is compared to observed topography. The calibration process ultimately hinges on quantification of the aggregation pattern of the basin through analysis of the cumulative area distribution. The effect of spatially heterogeneous erosivity is shown to be crucially important to reproduce the cumulative area distribution of observed topography.