Much research has been carried out on the pollutional strength of nonpoint source runoff and the potential effect of the runoff upon freshwater systems of the United States. This report is an attempt to pull together the more significant findings on the oxygen-demanding strength of both urban and rural nonpoint source runoff. The objectives were to survey the recent literature, especially EPA Research Reports, and to summarize the findings on loadings of oxygen consuming material discharged to freshwater by nonpoint source runoff. Once the loadings of oxygen-using material were available, the next objective was to estimate the impact of these loadings upon the dissolved oxygen resources of freshwater systems and the ecological effects upon freshwater environments. Unfortunately, there is a serious shortage of data upon surface accumulation rates, stream-side loading rates, and dissolved oxygen concentrations resulting from nonpoint source inputs all measured concurrently within the same watershed. The data available indicate that the oxygen-demanding loadings from urban runoff can be very significant, but that estimates of effects upon fish and other aquatic organisms must await more information.

"May 1981." Includes bibliographical references (pages 23-30).