ABSTRACT
Catastrophe theory provides a language for describing space-time changes in systems and is potentially applicable to fluvial processes. The theory, which is based on topology, indicates that all changes in the four dimensional natural universe proceed according to one of seven different singularities, or catastrophes. The cusp catastrophe seems likely to be useful to geomorphologists: it is characterized by abrupt and smooth changes, divergent and bimodal behavior, hysteresis, and stability of structure. The utility of catastrophe theory in geomorphology is limited as indicated by tests using data from arroyo systems and rapids in canyon rivers. Disadvantages of the theory include difficulty in identification of system control factors, definition of energy functions, and the generality of the theory. Advantages include a marriage of concepts of equilibrium and change, the stability of the change structure, and its perspective, which is unlike previous models. An evaluation of catastrophe theory in fluvial applications suggests that it has limited usefulness for the description of change, but in some situations it can provide a unifying mechanism for general concepts and specific observations.
