Chloride: A component of salt, and is a measure of human or animal waste inputs to a stream. Potential sources of chloride to a stream include direct input from livestock, septic system inputs, and/or discharge from municipal wastewater facilities. During winter months, elevated chloride levels in streams may occur as a result of road salt runoff to nearby streams. Average chloride concentrations in Iowa streams are 20 to 30 mg/L.
Dissolved Oxygen: The amount of oxygen dissolved in water. Measured in mg/L or ppm. Low DO can be harmful to aquatic organisms. Iowa has water quality standards for dissolved oxygen. Warmwater streams should have a minimum of 5 mg/L, while coldwater streams should have a minimum of 7 mg/L.
pH: A measure of a water's acidity. Changes in pH can be caused by atmospheric deposition of acid rain, the types of soils and bedrock that the water comes in contact with, wastewater discharges, and acid mine drainage. A pH of 7 is neutral; pH values greater than 7 are alkaline or basic, while a pH less than 7 is acidic. Average pH levels in Iowa streams are 8.1 to 8.4.
Water Transparency: A measure of water clarity and is affected by the amount of material suspended in water. As more material is suspended in water, less light can pass through the water, making it less transparent (or more turbid). These materials include soil, algae, plankton, and microbes. Transparency is measured on a scale from 0 to 60 centimeters. The higher the number, the more transparent the water.