In a preliminary study of the macrophytes in Portage Creek, Michigan distribution patterns were determined in relation to abiotic factors by the parameters of substrate cover and weight. Portage Creek shows the effect of industrial and urban effluents on a stream ecosystem, since the water flows from areas supporting a trout population to areas of gross pollution where only sewage fungi and bacteria grow. Oxygen content was reduced to some extent following the addition to the stream of the paper mill effluent, and it was further reduced near the Kalamazoo River. In the reach of the stream during which the oxygen was reduced, sewage sludge was extensive. Paper mill effluents have a profound effect on the macrophytes, that is, their complete elimination. The effect the individual additives would have on the macrophytes is not readily apparent, although upon cursory examination of the data and visual examination of the water it would appear the tenfold increase in turbidity would be the most obvious factor. (WRSIC abstract)