Alternative Compliance for New Developments

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Alternative Compliance for New Developments

• NPDES Permit Provision C.3.g
• Alternative Compliance Based on Impracticability
  and Requiring Compensatory Mitigation

Dan Cloak Environmental Consulting
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Outline

• Key Limitations of C.3.g
• Options for applicants
• Options for municipalities

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Key Limitations

• C.3.g applies only to stormwater treatment
• Site design must still minimize imperviousness
• Source control BMPs still required
• HMP requirements still apply
• Applicant must demonstrate
• Impracticability of on-site treatment
• Equivalent off-site treatment or other benefit
• Municipality must document and report each
  project granted alternative compliance
  

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Three Options for Applicants

• Participate in a Regional Stormwater Treatment
  Facility
  
• Demonstrate infeasibility on project site and
  implement compensatory mitigation on another
  site
  
• Obtain an exemption based on certain project
  characteristics (stated in the permit)
  

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Option 1 Regional Facility

• Extended Detention Basin
• Appropriate for drainage areas of 20 acres or
  more

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Option 1 Regional Facility

• Examples
• Pond or playing field in a park
• Existing lagoon or modified flood control basin
• Advantages
• No demonstration of infeasibility required
• Facility may be in a different drainage area
• Existing facilities can be used or modified
• Possible savings in land, capital, and
  maintenance costs
  
• Disadvantages
• Must plan, locate, construct, and maintain
• Must determine how applicants pay in and how
  much
  

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Option 2 Alternative Site

• Examples
• Retrofit an existing parking lot
• Fund pollutant remediation, habitat restoration,
  or other equivalent water quality benefit
  
• Advantage
• Avoid excessive costs or impracticability on
  difficult sites (e.g. hillside or 100 lot-line
  development)
  
• Disadvantages
• Must establish infeasibility of on-site
  treatment
  
• Must establish that off-site benefit is
  equivalent
  
• Design and mobilization costs to build two
  projects
  

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Option 3 Exemption

• Examples (categories specified in Permit)
• Development of a brownfield
• Low and moderate income housing
• Transit-village type development
• Advantage
• No compensatory mitigation required
• Disadvantages
• Categories are narrowly defined
• Must demonstrate impracticability of on-site
  treatment
  
• Must also demonstrate that alternative compliance
  would unduly burden the project financially

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Two Options for Municipalities

• Establish an Alternative Compliance Program
• Define criteria for infeasibility and
  impracticability
  
• Impracticability may include economic
  threshold
  
• Submit for Water Board review and approval
• Interim Alternative Compliance
• Municipality may review project-by-project
• Must show impracticability of on-site treatment
• Must establish equivalent treatment within six
  months
  
• Equivalent water-quality benefit projects that
  do not include treatment devices require Water
  Board approval