This study considered the receiving stream as an integral part of the bio-oxidation pond method of treatment with the objective being to provide a better understanding of the bio-oxidation pond - receiving stream system. As representative of this 'real world' situation with all of its variables, five existing central Oklahoma bio-oxidation ponds which had diverse loadings and designs were utilized. By observing these systems under varying climatic conditions, the effects of the bio-oxidation pond nutrients along with other pollutional parameters which were discharged into intermittent receiving streams were evaluated. Except for scouring, bio-oxidation ponds and bio-oxidation pond - receiving streams were found to behave essentially the same as the streams became a continuation of the pond. In addition to making biochemical adjustments, the streams lost much of their biological identity and assumed characteristics more closely associated with the biological loadings from the pond effluent. The most persistent algae in the systems were the flagellates (Euglenophyta) and the blue-green algae (Cyanophyta) as these plankters had little difficulty making the transition from their acclimated life in the pond to the stream. (WRSIC abstract))