2020 Total Ammonia Nitrogen Criteria Implementation Guidance - - PowerPoint PPT Presentation

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2020 total ammonia nitrogen criteria implementation
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2020 Total Ammonia Nitrogen Criteria Implementation Guidance - - PowerPoint PPT Presentation

Nov 14, 2022 171 likes •284 views

2020 Total Ammonia Nitrogen Criteria Implementation Guidance Michael Abbott, Chief Operating Permit Section Key Topics Purpose Alignment with criteria Default values Site-specific data Reasonable Potential Other considerations Questions

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2020 Total Ammonia Nitrogen Criteria Implementation Guidance

Michael Abbott, Chief Operating Permit Section

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Key Topics

Purpose Alignment with criteria Default values Site-specific data Reasonable Potential Other considerations Questions

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Purpose

Site-specific data New default values for pH and Temperature Does not replace or remove existing ammonia criteria Permit writer’s guidance

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Alignment with Criteria

304(a) federal CWA Magnitude, Duration, Frequency MDL (1-day acute criteria) AML (30-day chronic criteria) EPA discourages use, but for 4-day

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Default Values

Impact Parameters

Temperature pH

Ecoregions

50th percentile pH 75th percentile temperature

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Site-Specific Data

Default pH (50th percentile) Temperature (75th percentile) Non-Mixing Considerations = effluent Mixing Considerations = edge of ZID or MZ

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Reasonable Potential

Two Seasonal (default)

  • Monthly
  • Quarterly

Ammonia criteria

  • Ecoregion (default)
  • Site-specific data

Mixing Considerations

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Other Considerations

Cold-Water Fisheries Cool & Warm-Water Fisheries Early life stages present

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Questions

  • Thank you for comments!
  • Update permits page
  • Gov.delivery message
  • Memorandum, guidance, comments, and

responses.