ABSTRACT
Overpopulation is the most serious problem facing the world today, with too many people making too many demands on a natural environment which is increasingly under stress. Rivers are a fundamental part of that environment. Their behaviour is of interest to a wide variety of concerns, ranging from water supply, navigation and power generation, to recreation and aesthetics. One of their main attractions to human populations is their unidirectional water flow, which provides a continuously renewable resource, a rapid removal system for unwanted substances, and a valuable source of energy. Such features are also of vital importance to the vast range of aquatic plants and animals inhabiting the fluvial ecosystem (Boon, 1992). In addition to their resource associations, rivers represent a potential threat to human populations and property through floods, drought, pollution and erosion. Whether as resource or hazard, rivers have political, social and economic as well as physical relevance. Most nations depend on sustainable river management.
