Need for Metropolitan Water Balance Inventories

More water balance inventories, determining the quantity and quality aspects of the fate of water as it cycles through a metropolitan area, are needed for evaluation of the hydrological effects of urbanization and related development of strategies for resource management and environmental protection. A general accounting for the overall movement of water and pollutants can be ascertained by comparing such complete inventories over successive time intervals. The status of metropolitan comprehensive water resource systems analysis is outlined, system complexities are described, and the need for inventories is explained. Serious obstacles have impeded advances, but progress is being made in a few notable instances. Investments in such research world-wide are well below levels that could be justified by the economic and environmental importance of urban water resources