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

2. 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 - 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. 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. Aug 2007 – Nov 2007 – IDEM staff presented revised concept to interested parties. Governor’s Stakeholder meeting – March 7, 2008. Governor’s Stakeholder meeting – March 7, 2008. March 14, 2008 - Draft rule language based on revised concept circulated. March 14, 2008 - Draft rule language based on revised concept circulated.

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

4. 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 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. That the rule can be implemented by IDEM according to a clear, consistent, logical, and streamlined process.

5. 5 March 14, 2008 draft rule Sec 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. 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. A new permit limit is needed when there is a reasonable potential to exceed (RPE) any narrative or numeric water quality criterion.

6. 6 Reasonable Potential to Exceed 327 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). 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. 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. The preliminary effluent limit is influenced by the size of the mixing zone.

7. 7 Mixing Zones 327 IAC 2-1-4 & 327 IAC 5-2-11.4(b)(3) No universal mixing zone may be prescribed. No universal mixing zone may be prescribed. The Commissioner shall determine the mixing zone upon application by the discharger. 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 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. 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. 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. If the new or increased discharge is too small to require a permit limit based on RPE, then no antidegradation review is required.

9. 9 March 14, 2008 draft rule Sec 2: Definitions Many of the definitions are based on statutory definitions or definitions used in other rules. 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 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. IDEM will eliminate definitions if the term is not actually used within the rule.

10. 10 March 14, 2008 draft rule Sec 3: Antidegradation Standards Establishes minimum standards based on Tiers. 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. 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. 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. 11 March 14, 2008 draft rule Sec 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. 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. 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. These activities do not include BCCs, however IDEM is concerned about antidegradation implementation for mercury.

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

13. 13 March 14, 2008 draft rule Sec 6: De minimis 2 Options for non OSRW/EUW: 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. For OSRW/EUW de minimis is the representative background concentration.

14. 14 Option 1: No mixing zone or default technology based effluent limit Less data are needed to calculate a WQBEL without a mixing zone. 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). 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. Option 1 results in a consistent de minimis level as the calculation is independent of available receiving stream background data.

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

16. 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. 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. Option 2 will result in different de minimis levels depending on available receiving stream background data and the size of the receiving stream.

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

18. 18 March 14, 2008 draft rule Sec 8: Necessary Test A successful necessary test should show: 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. 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? Question: Should the question of “why the discharge is necessary at all” be answered separately?

19. 19 March 14, 2008 draft rule Sec 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. 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. The alternatives analysis should compare level of treatment with the cost of treatment – a “knee-of-the curve” type analysis.

20. 20 March 14, 2008 draft rule Sec 10: IDEM Review IDEM will provide opportunity for public comment on the necessary test and alternative treatment analysis. 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. 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. 21 March 14, 2008 draft rule Sec 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. 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. 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. IDEM will provide opportunity for public comment on the proposed water quality improvement project.

22. 22 Other issues not addressed in March 14, 2008 draft rule General permits 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; 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. 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. 23 Other issues not addressed in March 14, 2008 draft rule 401 Water Quality Certifications 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. 24 Proposed Antidegradation Implementation Procedural Steps