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IDEM Overview of March 14, 2008 Draft Antidegradation Rule

IDEM Overview of March 14, 2008 Draft Antidegradation Rule. Presented at the April 29, 2008 Antidegradation Stakeholder Meeting. Refresher: Recent History of Antidegradation Rulemaking. April 2005 - IDEM determined the April 1, 2005 second noticed draft would be difficult to implement.

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IDEM Overview of March 14, 2008 Draft Antidegradation Rule

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  1. IDEM Overview of March 14, 2008 Draft Antidegradation Rule Presented at the April 29, 2008 Antidegradation Stakeholder Meeting

  2. Refresher: Recent History of Antidegradation Rulemaking • April 2005 - IDEM determined the April 1, 2005 second noticed draft would be difficult to implement. • April 2005 – July 2007 – internal IDEM, OWQ workgroup met to take a fresh look at antidegradation implementation procedures and develop revised concept. • Aug 2007 – Nov 2007 – IDEM staff presented revised concept to interested parties. • Governor’s Stakeholder meeting – March 7, 2008. • March 14, 2008 - Draft rule language based on revised concept circulated.

  3. Internal IDEM antidegradation workgroup process • Gathered information about antidegradation from other states and EPA; • Reviewed comments received on the April 1, 2005 second noticed draft; • Identified and focused on the key issues raised; • Discussed potential ways to address the key issues; • Contributed to development of the March 14, 2008 draft rule language.

  4. IDEM Goals for draft Rule • That the rule meet the requirements of the Clean Water Act; comply with state law; and be consistent with existing state administrative rules. • That the rule can be implemented by IDEM according to a clear, consistent, logical, and streamlined process.

  5. March 14, 2008 draft ruleSec 1: Applicability • IDEM’s intent is to have the rule apply only when a new or increased discharge triggers the need for a new permit limit. • A new permit limit is needed when there is a reasonable potential to exceed (RPE) any narrative or numeric water quality criterion.

  6. Reasonable Potential to Exceed327 IAC 5-2-11.1(h) & 327 IAC 5-2-11.5 • The RPE process compares the projected effluent quality (PEQ) to the preliminary effluent limit (PEL). • If the projected effluent quality is greater than the preliminary effluent limit, then a permit limit is required. • The preliminary effluent limit is influenced by the size of the mixing zone.

  7. Mixing Zones327 IAC 2-1-4 & 327 IAC 5-2-11.4(b)(3) • No universal mixing zone may be prescribed. • The Commissioner shall determine the mixing zone upon application by the discharger. • For the Great Lakes Basin, preliminary wasteload allocations shall be calculated using a dilution fraction no greater than 25% of the stream design flow (327 IAC 5-2-11.4). • For the rest of the state, preliminary wasteload allocations shall be calculated using a dilution fraction no greater than 50% of the stream design flow.

  8. Potential result of RPE • If the new or increased discharge is too small to require a permit limit based on RPE, then no antidegradation review is required.

  9. March 14, 2008 draft ruleSec 2: Definitions • Many of the definitions are based on statutory definitions or definitions used in other rules. • IDEM will review the definitions for consistency of use within the rule itself and other rules. • IDEM will eliminate definitions if the term is not actually used within the rule.

  10. March 14, 2008 draft ruleSec 3: Antidegradation Standards • Establishes minimum standards based on Tiers. • All waters are presumed to be high quality waters (better quality than the water quality criterion), including OSRWs and EUWs. • However, OSRWs and EUWs are subject to the Tier 2.9 antidegradation standard, particularly, no new or increased loading of BCCs that causes a significant lowering of water quality.

  11. March 14, 2008 draft ruleSec 4: Non Significant Lowering • Identifies activities that, although they may result in a new or increased discharge, the discharge is at a level that will not cause a significant lowering of water quality. • For activities that qualify, no further antidegradation review is required. • These activities do not include BCCs, however IDEM is concerned about antidegradation implementation for mercury.

  12. March 14, 2008 draft ruleSec 5: NSL Justification • The applicant must demonstrate that their proposed discharge is a non significant lowering activity. • Question: Should this review be combined with the review of the application for the associated NPDES permit?

  13. March 14, 2008 draft ruleSec 6: De minimis • 2 Options for non OSRW/EUW: • Option 1: The more stringent of the WQBEL calculated without the benefit of a mixing zone or default technology based effluent limit. • Option 2: less than 10% of the unused loading capacity. • For OSRW/EUW de minimis is the representative background concentration.

  14. Option 1: No mixing zone or default technology based effluent limit • Less data are needed to calculate a WQBEL without a mixing zone. • Default technology based effluent limits may be difficult to derive as the federal effluent guidelines are insufficient (nonexistent or out-of-date for many parameters). • Option 1 results in a consistent de minimis level as the calculation is independent of available receiving stream background data.

  15. Option 2: Less than 10% of the unused loading capacity • Unused loading capacity is calculated similar to how RPE is calculated. • Sufficient data are needed to determine the representative background concentration and loading capacity of a receiving stream.

  16. Option 2: Less than 10% of the unused loading capacity (cont’d) • If a mixing zone was used to calculate RPE, then it should be considered when determining if a discharge is de minimis. • Option 2 will result in different de minimis levels depending on available receiving stream background data and the size of the receiving stream.

  17. March 14, 2008 draft ruleSec 7: significant lowering • Discharges that have a reasonable potential to exceed and are greater than de minimis are a significant lowering… • unless it is an activity listed in 4b (not 4c as typo indicates).

  18. March 14, 2008 draft ruleSec 8: Necessary Test • A successful necessary test should show: • why the discharge is necessary at all; and • that the discharge is providing a social or economic benefit. • Cost-effective pollution prevention must be applied to minimize the discharge. • Question: Should the question of “why the discharge is necessary at all” be answered separately?

  19. March 14, 2008 draft ruleSec 9: Alternatives Analysis • If the discharge is necessary for providing a social or economic benefit but cannot meet the default technology based effluent limits, then the applicant must examine alternative levels of treatment. • The alternatives analysis should compare level of treatment with the cost of treatment – a “knee-of-the curve” type analysis.

  20. March 14, 2008 draft ruleSec 10: IDEM Review • IDEM will provide opportunity for public comment on the necessary test and alternative treatment analysis. • IDEM will evaluate the necessary test and alternative treatment analysis to determine if the proposed significant lowering of water quality is necessary and provides a social or economic benefit.

  21. March 14, 2008 draft ruleSec 11: W Q Improvement Project • A water quality improvement project is required to offset the impact of any significant lowering of water quality in an OSRW or EUW. • Complete information on a proposed water quality improvement project must be submitted whether implementing the project or funding the project by paying a fee. • IDEM will provide opportunity for public comment on the proposed water quality improvement project.

  22. Other issues not addressed in March 14, 2008 draft rule • General permits • IDEM believes that the discharges permitted under the general permit rules should not cause a significant lowering of water quality. • IDEM will review the permit conditions found in the general permit rules to determine if: • they cause a significant lowering of water quality; • any changes are needed to the general permit rules to address any pollutant of concern and/or effluent limitations/conditions that may cause a significant lowering of water quality.

  23. Other issues not addressed in March 14, 2008 draft rule • 401 Water Quality Certifications • IDEM’s requirement for mitigation to offset discharge impacts authorized by a 401 water quality certification ensures that these discharges do not result in a significant lowering of water quality.

  24. Proposed Antidegradation Implementation Procedural Steps

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