Winter Water Quality Survey Of The Winnebago River

A water quality survey of the Winnebago River was conducted during February 1979. Water samples from eleven stream stations were collected in assessing the winter water quality and evaluating water quality changes that may have occurred since previous studies. In addition to the stream sampling, three municipal wastewater treatment plant effluents were sampled. Results of the survey indicated poor water quality in the upper half of the Winnebago River (above Fertile) and good water quality in the remainder of the basin. Four violations of the Iowa water quality standard for dissolved oxygen occurred in the upper half of the Iowa reach of the Winnebago River. The violations at the two stations upstream from Forest City were probably due to winter conditions of low flow and thick ice cover. The violations at the two stations downstream from Forest City were probably due to these same two factors in conjunction with the effluent from the Forest City wastewater treatment plant. The Lake Mills wastewater treatment plant was not in compliance with its biochemical oxygen demand permit limitation. The Mason City plant effluent had only a minimal impact on the water quality of the Winnebago River.