ABSTRACT
This chapter explains optimal models of river branching angles. At a junction, branching angles are defined as the angles formed by the tributaries and the axial prolongation of the main (receiving) stream. The application of the optimality principle to the geometry of branching systems was first introduced in biology. The chapter explains the effect of symmetry ratio and negative exponent and the relationship between the symmetry ratio and optimal branching angles for symmetrical and asymmetrical branching. Field measurements undoubtedly improve the performance of the optimal model and provide for a much better test. The chapter describes assessment of the adequacy of the model. The test of the optimal angular geometry model is to assess whether it has any capacity for predicting the actual angles. The optimality principle affords a general theoretical approach to the investigation of river branching angles. The optimal angular geometry models were originally designed for biological trees.
