Management of the world's water resource is undergoing a momentous shift. New approaches to complex river development slowly are according greater recognition to its environmental limits and consequences. These approaches are departures from the preoccupation with single-purpose water development at the beginning of the twentieth century and are radical extensions of the concept of integrated or complex river development that had gained acceptance by midcentury. Complex utilization means the integrated management of river flow and quality to serve multiple purposes. Thus, it is not limited to river basin management. It may well include segments of territory, such as metropolitan areas or a national plan (as in Kenya), cutting across several river basins. It may involve a combination of parts of two or more basins in systems of diversion and management which incorporate actions throughout a larger area, as in the proposed transfer of water from north-flowing to south-flowing streams in the USSR.