ARE RIVER BASINS OPTIMAL CHANNEL NETWORKS

Drainage networks generated with a simulation model based on the scali ng relationship between slopes and areas were found to have total ener gy expenditure values very near the minimum value of optimal channel n etworks. Using this model to grow networks inside the boundaries of re al basins, it is shown that the drainage networks identified with the aid of digital elevation maps in such basins tend to organize themselv es in configurations that minimize total energy expenditure. The role of perturbations in the search for configurations with lower energy an d the existence of unstable equilibrium landscapes are also examined.