Water Quality Division

Assessment of Stream Water Quality

One of the most important variables to the overall aquatic health of a waterbody is its water quality. Water quality monitoring consists of monitoring the physical and chemical properties of water for purposes of determining whether the water is of sufficient quality to support its beneficial uses. Anything dissolved in water, and much of the fine particulate matter suspended in water is considered part of the chemical habitat of an aquatic organism. Just as organisms have a preferred physical habitat, they also have a preferred chemical habitat. Standard parameters that are collected during water quality monitoring include:

• Temperature (ˇCelcius),
• Specific Conductance (ˇseimen),
• pH (standard units),
• Dissolved Oxygen (milligrams per liter or mg/l),
• Instantaneous Discharge (cubic feet per second),
• Alkalinity (mg/l),
• Turbidity (Nephelometric Turbidity Units),
• Total Kjeldahl Nitrogen (mg/l),
• Ammonia (mg/l),
• Nitrate (mg/l),
• Nitrite (mg/l),
• ortho-Phosphorus (mg/l),
• Total Phosphorus (mg/l),
• Total Hardness (mg/l),
• Sulfate (mg/l),
• Chloride (mg/l),
• Total Suspended Solids (mg/l), and
• Total Dissolved Solids (mg/l).

Additional parameters might include concentrations of various heavy metals, pesticides, fecal bacteria, or other organic compounds. These measurements are generally collected at least once a month to characterize a stream's overall water quality. These concentrations are compared to Water Quality Standards using a standardized protocol described in Oklahoma's Use Support Assessment Protocols to evaluate the water quality of the waterbody in question.

Stream water quality is assessed in conjunction with stream habitat and stream aquatic communities to determine the stream's overall health.