Water: Module 5
Basic Course: Key Concepts (Module 5.l)
- Module 1: Overview
- Module 2: Use
- Module 3: Criteria
- Module 4: Antidegradation
- Module 5: Flexibilities
- Flexibility Mechanisms in Water Quality Protection
- CWA Goals
- Feasibility of Controls
- Feasibility Factors
- The Economic Factor
- Potential Parameters
- Addressing Local Conditions
- When Site-Specific Criteria Are Allowed
- Temporary Modification to Water Quality Standards
- When Variances Are Allowed
- Discharger Grace Period
- Module 6: Review
- Certificate of Completion
The water quality program includes mechanisms that allow flexibility in addressing local circumstances that may arise.
For example, a designated use can be removed/revised if the State/Tribe finds that attaining the use is not feasible. If the use addresses the CWA's 101(a)(2) goal, then the change must be supported by a formal use attainability analysis.
Similarly, states/tribes have the flexibility to modify national criteria recommendations in order to adopt site-specific criteria that reflect local conditions in a particular water body.
Also, the regulations afford the flexibility to grant a variance that temporarily modifies the State/Tribe's standards in order to allow a particular discharger (or dischargers) to determine what standards are attainable over the long term. The temporary modification usually regards a specific pollutant. Thus, the underlying standards remain in place. To grant such a variance, the State/Tribe must demonstrate that attaining the currently designated use is not feasible in the short term due to one of the six factors listed in 40 CFR 131.10(g).
If authorized by the State/Tribal water quality standard or implementing regulations, a discharger can also be allowed a compliance schedule to take the necessary actions to come into compliance with permit limits based on new, revised, or newly interpreted water quality standards. This involves establishing a compliance schedule as part of the discharger's NPDES permit and including interim requirements.