The Arkansas River is subject to many types of pollution downstream from the Oklahoma-Kansas State line, and its inferior quality together with its erratic flow pattern has caused it to be largely abandoned as a source of municipal and industrial water supply. Currently, the Arkansas River is not directly used as a source of public supply in any part of the basin in either Oklahoma or Arkansas. In general, the chemical concentration of the river water increases downstream from the Oklahoma-Kansas State line to Tulsa because of tributary inflow from the Salt Fork Arkansas River and the Cimarron River, both streams being sources of large amounts of natural salts and industrial wastes. A decrease in concentration of dissolved solids is noted downstream from Tulsa due to tributary inflow from the Verdigris, Neosho, and Illinois Rivers; another increase in concentration occurs with tributary inflow from the Canadian River, which is largely oilfield wastes. A progressive decrease in concentration is noted as the river flows through Arkansas to the Mississippi River, because all major tributaries below the Canadian River have a dilution effect upon the chemical concentration of the Arkansas River water. Proposals for storage and regulating reservoirs on the Arkansas River in both Oklahoma and Arkansas have been made by the Corps of Engineers and others. Additional proposals are being considered in the present Arkansas-White-Red River Basin Inter-Agency Sub-Committee studies. If constructed, these reservoirs will provide an opportunity for control of flow and beneficial use of Arkansas River water both at and downstream from these sites. Impoundment alone will greatly reduce the extremes in water quality, and by reasonable control of municipal and industrial wastes, the water at some points on the river would be comparable in quality to many existing municipal and industrial supplies in the basin.