Senate Resources and Environment Committee bones up on anti-degradation

DEQ representatives presented three rules regarding anti-degradation this week to the Senate Resources and Environment committee.

The first of the proposed rules was generated as a result of a lawsuit over the inadequacy of Idaho lack of a water degradation plan, a suit which has since been held, pending legislative action.

Anti-degradation implementation plans and policies are a requirement of the clean water act. DEQ officials said Idaho has the policy but no implementation plan.

For the purposes of the presentation, DEQ representatives outlined some definitions:
- “Total Maximum Daily Load” (TMDL) refers to a restoration standards when water quality is below standards.
- Anti-degradation,” on the other hand, refers to maintaining water quality that is better than standards.
- “Ambient water quality” is what exists now.
- “Assimilative capacity” is what a water can assimilate and not impact it status.
- “Insignificant discharges” are defined as:
- Based on measure of ambient water quality and assimilative capacity.
- Must have a 10 percent assimilative capacity cap
- 10 percent ambient concentration spreads insignificant discharges out to more than one permit
- Insignificant discharge does not have to conduct additional analysis
- Allows agency to focus resources.

For the purposes of this rule, bodies of water have been categorized into three tiers:
- Tier I: Water quality at or below standard. No further impairment of aquatic life or recreational uses are allowed. A TMDL has been developed for Lake Lowell, for example as a Tier I body.
- Tier II: High water quality. Degradation of water quality is allowed with justification (socioeconomic)
- Tier III: Highest quality waters. No degradation allowed. The dividing line between this and Tier II waters is unclear. Some groups have unsuccessfully tried to change a body of water from II to III. In Idaho, we don’t have any Tier III waters, so our focus is on Tier I and II waters.

All waters get a Tier I review – which examines protecting and maintaining the existing water quality and existing uses. Tier II analysis is for activities that may cause degradation: looking at what other source controls are there to ensure that they’re adequate, as well as what is the best option for the money to maintain and protect the existing water quality. A Tier II analysis may allow significant degradation to accommodate important economic or socioeconomic development.

Under this categorization, there are some ACOE Nationwide permits, and maybe industrial Storm water permit under the EPA that might need further Tier II review, but most existing general permits would not need further review.

The pending rule describes how Idaho will implement anti-degradation. There are four main issues:

- Classification of water bodies - which waters get what protection?
- Insignificant discharges - What activities do not need full tier II analysis?
- Tier II analysis – how do we determine if anti-degradation is necessary and important?
- General permits – how do we address anti-degradation?

The rule as proposed is one that DEQ representatives say will withstand court challenges and as such is one that EPA will approve.