Recent Changes in Phase II MS4 Permitting

Transcription

1 Recent Changes in Phase II MS4 Permitting Georgia Association of Flood Management - Spring Conference March 11-14, 2013 Lake Lanier Islands, Georgia GA EPD - Watershed Protection Branch Wastewater Regulatory Program Emily Wingo, CFM Environmental Specialist

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3 Today s Presentation Addresses: The differences between Georgia s 2007 and 2012 Phase II MS4 permits ; Some explanation of why the changes were needed; and How permittees are impacted by the most significant changes.

4 Background Federal law (40 CFR 122) requires certain cities and counties within urban areas to obtain NPDES coverage for their stormwater discharges. Cities/counties that are within urban areas (determined by the US Census) with populations under 100,000 are regulated as Phase II Municipal Separate Sewer Systems (MS4). Larger cities/counties are regulated as Phase I MS4s. There are currently 87 cities/counties covered under one NPDES Phase II general permit (GAG610000) for storm water discharges.

5 Background (cont.) EPD is delegated by EPA to administer the NPDES permitting program. In addition to the Phase II Small MS4 Permit, Georgia also administers the Phase I Large and Medium classes of MS4 permits. The Phase I Medium MS4 permit reissuance in 2010 was a learning experience for EPD. EPA challenged the permit as lacking specific, measurable goals, concluding it could be issued but would have to be revised within 2 years. This resulted in the 2010 Phase I Medium Permit being issued for only a 2-year rather than 5-year period.

6 What Occurred to Make EPA See MS4 Permits Differently? What occurred to make EPA require more specific, measurable goals within the NPDES MS4 permits? The National Research Council (NRC) published the results of a study of non-point pollution and EPA s approach to regulating stormwater discharges in 2009, commissioned by EPA. The study showed that the quality of the nation s waters was continuing to decline from non-point source pollution and that positive impacts resulting from the current stormwater permitting system could not be documented.

7 What Occurred to Make EPA See MS4 Permits Differently? (cont.) EPA began tightening stormwater permits nationwide and in April 2010 issued the MS4 Permit Improvement Guide. EPA has discussed at length major revisions of the Federal stormwater regulations (40 CFR 122) due out as a proposed rule this summer. The proposed rule is expected to incorporate some of the elements of the MS4 Permit Improvement Guide and other reqiurements investigated by EPA in relation to the NRC study.

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9 EPA s MS4 Permit Improvement Guide Is a guidance document that EPA is using to determine what MS4 permits need to contain. Emphasizes that permit provisions should be clear, specific, measureable, and enforceable. States that permits should contain a performance standard for post-construction that is based on the objective of maintaining or restoring stable hydrology to protect water quality of receiving waters or another mechanism as effective. Had a significant impact on the most recent Phase I Medium and Phase II Small MS4 Permit re-issuances in Georgia.

10 What s Changed in the 2012 Permit? FORMAT The 2007 permit contained general language requiring the permittee to develop a Storm Water Management Plan (SWMP) that became a part of the permit once approved. Although EPD provided guidance on how the SWMP should be written and what it should contain, the permittee had a good deal of flexibility in determining what their program elements would entail. The 2012 permit states the minimum specific BMPs and measureable goals in tables within the permit, listing them as required elements. These elements must now be incorporated into each permittee s SWMP.

11 What s Changed in the 2012 Permit? (cont.) FORMAT (cont.) Impact -The impact of these changes is to provide specific measurable and enforceable goals, as instructed by EPA in discussions of the Phase I Medium MS4 permit renewal and as addressed in EPA s Permit Improvement Guide.

12 What s Changed in the 2012 Permit? (cont.) Post-Construction - GSMM The 2007 permit required Phase II permittees to adopt the development requirements of Georgia s Stormwater Management Manual (GSMM) or an equivalent design manual by 12/9/08, and have a program that ensures that the design standards are implemented. The 2012 permit incorporated the specific postconstruction requirements from the GSMM for stormwater runoff reduction, stream channel protection, overbank flood protection, and extreme flood protection.

13 What s Changed in the 2012 Permit? (cont.) POST-CONSTRUCTION - GSMM (cont.) Impact -The impact of these changes is to provide greater clarity on what the program requires, creating measureable and enforceable permit goals. For permittees who had not interpreted the 2007 permit to apply to new development and redevelopment over 5,000 SF in size, the requirement is now clear. And the specific design criteria to be used, such as the requirement to provide a stormwater management system designed to remove 80% of the average annual post-development TSS load, is clearly spelled out.

14 Rain garden Parking lot bioretention

15 What s Changed in the 2012 Permit? (cont.) Post-Construction GI/LID GI = green infrastructure LID = low impact development. GI/LID describes stormwater practices that infiltrate, reuse and/or evapotranspire rainwater rather than collect and discharge it to surface water through gray infrastructure like pipes and culverts. EPA is focusing on GI/LID as a means to help maintain and restore the water quality of receiving waters while development is occurring. The 2007 Permit did not address green infrastructure.

16 What s Changed in the 2012 Permit? (cont.) Post-Construction GI/LID (cont.) The 2012 Phase II permit gets the small MS4s started on the path that Phase I Large and Medium MS4s have been implementing for at least one permit cycle, checking to see if their building codes and ordinances prohibit GI/LID and coming up with revisions if they do. Impact EPA expects the results to be less impact from development on surface water quality, and that these requirements will help restore some waterbodies to their designated use. For permittees, this is additional work, but work that hopefully supports continued, sustainable growth in their communities.

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19 What s Changed in the 2012 Permit? (cont.) Inventory, maintenance and inspection The 2007 Permit contained the general statements about sewer system mapping, and operation and maintenance program requirements found in the Federal regulations. Georgia further clarified these requirements through SWMP guidance and reviews. This allowed permittes a lot of flexibility in development of their system maps and inventory.

20 What s Changed in the 2012 Permit? (cont.) Inventory, maintenance and inspection (cont.) The requirements in the 2012 Permit are very specific as a result of the emphasis on measurable and enforceable permit requirements. Permit requirements include the mapping of all MS4 outfalls and receiving streams, and the mapping and inventorying of all catch basins, ditches, detention/retention ponds, and storm drain lines. Impact Cities/counties that were mapping and inventorying other or fewer MS4 components than those specifically listed in the 2012 Permit will have to revise or expand their programs to include these specific elements.

21 What s Changed in the 2012 Permit? (cont.) Impaired waters In the 2007 Permit, permittees were required to take steps to reduce the pollutant of concern (POC) in their discharge to non-supporting waterbodies to the maximum extent practicable, (MEP) only if an approved TMDL existed. In the 2012 Permit, the requirements are extended to MS4 discharges to non-supporting waterbodies, with or without an approved TMDL.

22 What s Changed in the 2012 Permit? (cont.) Impaired waters (cont.) 2012 Permit requirements are segregated by population. For MS4s with populations under 10,000, the permittee must develop an Impaired Waters Plan. This plan must include outfall mapping and BMPs to reduce the POC to the MEP. For MS4s with populations over 10,000, permittees are required to develop a Monitoring and Implementation Plan. This plan includes mapping and BMPs to be used, and monitoring of either the MS4 outfalls or receiving stream to determine effectiveness of the chosen BMPs.

23 What s Changed in the 2012 Permit? (cont.) Impaired waters (cont.) The 2012 Permit also specifically requires an evaluation of the effectiveness of the BMPs used and their modification if necessary. These requirements satisfy EPA regulations for permitting discharges to impaired waterbodies (e.g., shall not cause or contribute to an impairment). Impact - The anticipated impact is a reduction of non-point source pollutant loading to impaired waterbodies, but also the addition of scope to MS4 duties.

24 What s Changed in the 2012 Permit? (cont.) Enforcement Response Plan The MS4 Phase II Permit has always required the permittee to have the ability to enforce the requirements of the permit that are reflected in the SWMP as programs the MS4 will execute. Illicit Discharge Detection and Elimination and Construction Site Storm Water Runoff Control are two areas where the need for enforcement is evident.

25 What s Changed in the 2012 Permit? (cont.) Enforcement Response Plan (cont.) In the 2012 Permit, the enforcement information for the MS4 is pulled together into a response plan that explains which ordinances will be used, including citations of specific ordinance sections, and what progressive steps will be taken to enforce the provisions of the permit. Impact Although all existing permittees already have enforcement procedures, the ERP is anticipated to become a valuable resource that creates more consistent enforcement and expedites enforcement decisions while also serving as a measureable and enforceable goal for the permit.

26 Useful Links NPDES General Permit for Phase II Stormwater Discharges From Small MS4s (December 2012) _MS4_PhaseIISmall_GAG610000_Y2012Dec6.pdf STORM WATER MANAGEMENT PROGRAM GUIDANCE - Phase II MS4 Storm Water Management Program Preparation (January 2013) EPA s MS4 Permit Improvement Guide (April 2010) ater

27 Emily Wingo (404)