ABSTRACT
Deteriorating water quality is a threat to water resources and wildlife in many parts of the world. Much of the problem has been generated by industrialization and urbanization, from surface and atmospheric pollution. The earliest human impact upon water quality came from clearing the land for agriculture, which increased runoff velocities and sediment yields. Despite recent concern over acid rain, surface sources continue to dominate water pollution. Organic pollution tends to be relatively short-lived, but it can produce devastating effects and it continues to be the major concern for drinking water quality in the tropics. The recent review of operating strategy within the Rhine delta works combine water quality with sedimentation modeling to evaluate various operating scenarios. Many states have now banned industrial development above aquifers and most exercise some control over discharges entering groundwater as the most cost-effective way of guaranteeing drinking water quality.
