THE EFFECT OF SPATIAL HETEROGENEITIES ON GEOMORPHIC EXPRESSION IN A MODEL OF BASIN EVOLUTION

Spatial variability is a basic component of all natural systems. The s ystem being studied here is the topography of an evolving drainage bas in. Spatially heterogeneous erosivity within the drainage basin influe nces the structure of the drainage network, the roughness of small-sca le features, and the overall appearance of the simulated topography. T he presence of heterogeneities does not simply blur and smear analytic al relationships. The heterogeneities themselves introduce new structu re to the organization of the drainage Basin. Three measures, the slop e-area relationship, the cumulative area relationship, and the hypsome tric distribution, are all systematically affected by spatial heteroge neity. We will demonstrate how and why these relationships are affecte d and also how different structures in the heterogeneities themselves are manifested in the resulting simulated topography.