DISSOLVED-OXYGEN CHARACTERISTICS OF WISCONSIN STREAMS

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