Temperature Governs the kinds of aquatic life that can live in a stream. For instance, streams must be cooler than 61 degrees Fahrenheit for salmon to successfully spawn. Turbidity A measure of water clarity - how much the material suspended in water decreases the passage of light through the water. A term used to indicate the alkalinity or acidity of a substance as ranked on a scale from 1.0 to 14.0. Neutral pH is 7.0.
Acidity increases as the pH gets lower.
Typically produced by the decay of organic material such as dead plants or animals, or excrement from feedlots or sewage. Arsenic Known to occur naturally in the soils of the Stillaguamish watershed. Part of the TMDL study would determine whether human activities in the area are increasing its release. Copper, Lead and Nickel Metals that are harmful to fish and other aquatic life.