Current Assessment Methods, 2006 Water Quality Report to Congress

Water quality standards define goals for a waterbody by:

• designating uses,
• setting criteria to protect those uses, and
• establishing provisions to protect water quality.

To evaluate the status or condition of a given waterbody, field staff look to the quantitative and qualitative criteria associated with a designated use. The following are general guidelines for different types of waters and what values are associated different levels of quality. Note that these guidelines are informal and they haved evolved over time. Updates and formalization of assessment thresholds are currently underway.

Also note that with the greater availability of portable devices, DNR staff have greater access to continuous data rather than instantaneous data. Thus, for dissolved oxygen, a single instantaneous value of less 5 mg/l d.o. may not constitute a problem. However, continuous data showingrepeated (frequency), very low (magnitude), and prolonged (duration) d.o. values would carry much more weight in determining that a water was not meeting its at tainable use.

Fish and Aquatic Life, Rivers

All surface waters are considered appropriate for the protection of fish and other aquatic life. Surface waters vary naturally with respect to physical factors based on natural conditions that influence temperature, flow, and habitat, whichin turn define the totential for biological potential.

Wisconsin recognizes the following sub-categories of the fish and aquatic life use designation and applies the assessment metrics associated with the community listed:

Coldwater Community: Streams capable of supporting a cold water sport fishery, or serving as a spawning area for salmonids and other cold water fish species. Representative aquatic life communities associated with these waters generally require cold temperatures and concentrations of dissolved oxygen that remain above 6 mg/L. Since these waters are capable of supporting natural reproduction, a minimum dissolved oxygen concentration of 7 mg/L is required during times of active spawning and support of early life stages of newly-hatched fish.

Warmwater Sport Fish Community: Streams capable of supporting a warm water-dependent sport fishery. Representative aquatic life communities associated with these waters generally require cool or warm temperatures and concentrations of dissolved oxygen that do not drop below 5 mg/L. And

Warmwater Forage Fish Community: Streams capable of supporting a warm water-dependent forage fishery. Representative aquatic life communitiesassociated with these waters generally require cool or warm temperatures and concentrations of dissolved oxygen that do not drop below 5 mg/L.

Limited Forage Fish Community: Streams capable of supporting small populations of forage fish or tolerant macro-invertebrates that are tolerant of organic pollution. Typically limited due to naturally poor water quality or habitat deficiencies. Representative aquatic life communities associated with these waters generally require warm temperatures and concentrations of dissolved oxygen that remain above 3 mg/L.

Limited Aquatic Life Community: Streams cacapable of supporting macroinvertebrates or occasionally fish that are tolerant of organic pollution. Typically small streams with very low-flow and very limited habitat. Certain marshy ditches, concrete line-drainage channels, and other intermittent streams. Representative aquatic life communities associated with these waters are tolerant of many extreme conditions, but typically require concentrations of dissolved oxygen that remain above 1 mg/L.

Fish and Aquatic Life, Lakes

Fish and Aquatic Life Use status of Wisconsin Lakes is generally evaluated by trophic state index (TSI) scores derived from chemical, physical, and satellite data.

Public Health

Public Health and Welfare waters are indicated as not meeting potential uses if there is a specific advisory in place. For more information, refer to Fish Consumption Advisories.

Recreation

Recreational Use - All surface waters are considered appropriate for recreational use unless a sanitary survey has been completed to show that humans are unlikely to participate in activities requiring full body immersion.

Drinking Water Supply

Public Health & Welfare - All surface waters are considered appropriate to protect for incidental contact by humans. Some are even protected further since they serve as a drinking water supply to nearby communities.

Read the 2006 Assessments, including information on impaired waters page.