Biochemical Oxygen Demand (BOD): Oxygen is not only required for the survival of most living organisms, but is needed to decompose organic material. Organic materials accumulate in bottom sediments and support microorganisms, including bacteria, which consume oxygen as they break down the materials. The amount of oxygen required for the decomposition of organic material and the oxidation of chemicals in the water during the storage period is a measurement known as the BOD.

Chemical Oxygen Demand (COD): Like the BOD, the COD also refers to the amount of oxygen used during oxidization (the breakdown of materials using oxygen). The COD refers to both the organic matter and the inorganic oxidizing matter found in bottom sediments of a stream. It is also referred to as the oxygen consumed.

Conductivity measures a body of water's ability to carry an electrical current. This ability depends on dissolved ions, their total concentration, mobility, valence, and relative concentrations in the water temperature. In general, as the pollutant load to natural water increases, the concentration of dissolved ions increases. High conductivity values generally indicate high levels of pollution.