Before upgrading the Southwest Wastewater-Treatment Plant near Springfield, Missouri, to tertiary treatment, adverse water quality conditions resulting from discharge of wastewater effluent to Wilson Creek were documented in the creek and in the James River. About 7 years after the upgrading of the treatment plant, traveltime, reaeration, and water quality characteristics were determined in Wilsons Creek and the James River. Traveltime was measured once in Wilsons Creek and twice in the James River during low-flow conditions. Traveltimes in the James River were estimated for discharge between 55 and 200 cu ft/sec at a site near Boaz. Reaeration coefficients were calculated for five reaches in Wilsons Creek and the James River using the modified-tracer technique. Calculated reaeration coefficients were compared with coefficients predicted by twelve empirical equations and one equation was chosen that best fit the data. Water quality data were collected during two 44-hr periods, August 14 to 16, 1984, and July 23 to 25, 1985. Samples were collected at the outflow of the Southwest Wastewater Treatment Plant at seven sites along Wilsons Creek and the James River. Dissolved-oxygen concentrations in Wilsons Creek and the James River were all larger than Missouri 's water quality standard of 5.0 mg/l. Ammonia concentrations and 5-day carbonaceous biochemical oxygen demands were small, which indicated that the oxygen consumption by oxidizing ammonia and carbonaceous organic materials would be insignificant. Measured streambed oxygen demand in the James River was largest directly downstream from Wilsons Creek. (USGS)
