Water Quality Issues to Consider

What's Required Under Oregon Law

Water Quality Standards and Benchmark Limitations

Water Quality Standards (WQS) are the goals set by each state to maintain water quality under the Clean Water Act. In Oregon, the DEQ sets water quality standards in two steps. First, the DEQ determines the existing or potential uses for each water body. Designated uses are determined by basin and are available on the DEQ website in the Oregon Designated Uses Table. Uses may include recreation, fishing, aquatic life, public water supply, and irrigation. Then, the agency sets criteria necessary to maintain those uses. Criteria can be numeric or narrative. The goal of BMP implementation is to comply with the water quality standards codified in the Oregon Administrative Rules which set forth criteria for various pollutants including bacteria, dissolved oxygen, pH, total dissolved solids (TDS), toxic substances, and turbidity as well as basin-specific criteria.

Under a 1200-C NPDES permit, the site operator is required to construct facilities (temporary and/or permenant) such as diversion dikes or vegetative buffer zones, and implement specific practices in order to prevent erosion, control runoff and sedimentation, and meet other applicable standards during the construction project.

Questions to consider:

• Are the benchmarks established by the DEQ adequately protective in light of the designated uses of the receiving waterway?
• Are the monitoring requirements under the permit adequate to protect against pollution risks posed by construction-related activities?

Best Management Practices (BMPs) specific to each construction site are to be identified within the ESCP. It is the operator’s responsibility to maintain all BMP’s during each stage of the project.

The EPA requires that storm water discharges permitted under the NPDES program meet water quality standards, but does not stipulate specific design standards for individual BMPs. The DEQ has compiled a list of recommended BMPs to be instituted at construction sites. These recommended practices are aimed at controlling runoff, preventing erosion and controlling sediment. It is up to the site operator to identify the most necessary and efficient BMPs to implement at the construction site in order to meet these objectives. However, if the operator opts not to implement one or more BMPs recommended by the DEQ, the he/she must provide a rationale for doing so.

Example Best Management Practices

Questions to consider:

• Are the selected BMPs adequate to prevent excess stormwater runoff and erosion from occuring on or near the proposed construction site following a rain event?
• Has the applicant provided proper rationale for any BMPs it has chosen NOT to implement?

Impaired Waterways

The Clean Water Act requires that Oregon identify waterbodies that are threatened or that don’t meet basic water quality standards. These rivers, streams, lakes and bays are listed on the state’s “303(d) list” as water quality limited for the specific parameters that exceed state standards. (ie: temperature, turbidity, bacteria, etc.). You can find your local waterbodies on the DEQ’s water quality assessment database to determine if they are water quality limited.

The 303(d) list also includes the prioritization and plan for bringing each waterbody back into compliance with water quality standards. States set a Total Maximum Daily Load (TMDL) for each waterbody for each pollutant that currently exceeds standards. Every permit that includes a discharge into a 303(d) water quality limited water is required to adhere to the TMDL, considering that the TMDL is the overall limit that applies to all the dischargers in the area. Essentially, each discharger gets a “share” of the total discharge allowed under the TMDL for each specific pollutant/parameter.

Questions to consider:

• Are additional measures being taken to protect already impaired waterways affected by the proposed construction project?
• Are the indicated measures adequate to protect the impaired waterway?
• Is the agency allowing a new discharge of a pollutant for which the receiving waterway is already impaired?