Water quality standards are established to protect beneficial uses of the State's waters. Beneficial uses are designated for each water of the state, many for all waters in a basin, in the Oregon Administrative Rules for water quality standards.
Beneficial uses include:
- domestic water supply
- industrial water supply
- water contact recreation
- livestock watering
- aesthetic quality
- fish and aquatic life
- wildlife and hunting
- commercial navigation and transportation
When a water quality standard is established, the first step is to identify the beneficial uses sensitive to the parameter. Then criteria are established based on the levels needed to protect the sensitive beneficial uses. For example, the uses typically most sensitive to dissolved oxygen are fish and aquatic life. Fish and other aquatic organisms need an adequate supply of oxygen in the water to be healthy and productive. In this case, the criteria identify minimal amounts of dissolved oxygen that need to be in the water to protect the fish. In other cases, as with many of the toxic pollutants, the criteria may identify the maximum amount that may be in the water without risk to the aquatic biota or to human health. For other parameters, such as bacteria or some toxic compounds, human health is the most sensitive beneficial use.
Oregon beneficial use designations