DISSOLVED-OXYGEN CHARACTERISTICS OF WISCONSIN STREAMS

Dissolved Oxygen (DO) was continously monitored at nine rural stream sites throughout Wisconsin. Both cold and warmwater sites had similar mean annual mean DO concentrations. DO minima were due to nighttime respiration and storm runoff with the storm losses being the most severe. A majority of DO standard violations (<5.0 mg/l) took place when daily mean water temperatures were above 20-degrees-C. Violations were more frequent at warmwater sites, even though coldwater sites were generally found to be more undersaturated.