New UDC Ch' 15 Requirements: Stormwater Management Plan and Water Quality Impact Study

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New UDC Ch. 15 RequirementsStormwater
Management PlanandWater Quality Impact Study

• February 1, 2008

Presented by Melissa A. Guilbeau, AICP City of
Baton Rouge-Parish of East Baton Rouge Department
of Public Works Infrastructure Planning Division
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Todays Presentation

• Performance
• Previous Requirements
• New Requirements
• Documentation
• Previous Requirements
• New Requirements
• Stormwater Management Plan
• Water Quality Impact Study

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PerformancePrevious Requirements

• Drainage
• Provide capacity for a 10-year storm

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PerformanceNew Requirements

• Drainage
• Provide capacity for a 10-year storm

• Water Quality
• Treat or retain on-site all first flush
  stormwater pollutants that originate from the
  site post-construction (UDC Sec. 15.16.C) or as
  required by DEQ TMDLs

First Flush is the first 60 minutes of a 10-year
storm (UDC Sec. 15.1.B)
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UDC Section 15.12.J.4.a.Watershed Specific
Mitigation

• What if I cannot practicably fully treat
  stormwater discharge as defined in UDC Sec.
  15.16.C?
• Provide such treatment in an off-site facility OR
• Pay a stormwater off-site management fee
• Fee determined by Planning Commission
• Will be used to mitigate the impacts in the same
  watershed as the development

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UDC Section 15.12.J.3.a.Waiver of specific
pollutant treatment

• Waivers to treat specific water pollutants may be
  issued if
• Developer provides documentation proving that
• Specific pollutant does not exist on-site and
• Will not be generated by proposed development
• DPW concurs and approves

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DocumentationPrevious Requirements
DIS
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DocumentationNew Requirements
SMP
DIS
WQIS
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Stormwater Management?Construction vs.
Post-Construction

• Construction
• Storm Water Pollution Prevention Plan (SWPPP)
• No new or changed requirements!

• Post-Construction
• Stormwater Management Plan (SMP)
• New UDC Ch. 15 requirement!

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UDC Section 15.13Stormwater Management Plan
SMP
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UDC Section 15.13Stormwater Management Plan

• Recommend specific drainage and stormwater runoff
  quality improvements
• Drainage capacity for 10-year storm
• Treat or retain on-site all first-flush
  stormwater pollutants that originate from the
  site post-construction

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UDC Section 15.13Stormwater Management Plan

• Shall include
• Location of development
• Existing Conditions land cover, contours, soil
  types, estimated pollutant load
• Proposed Development land cover, contours,
  empirically expected pollutant load, proposed
  drainage and stormwater BMPs
• Plan Implementation detailed description of the
  specific proposed drainage and stormwater BMPs
• Maintenance how the proposed improvements will
  be maintained

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UDC Section 15.13Stormwater Management Plan

• Must be consistent with
• Drainage Impact Study
• Water Quality Impact Study
• when either or both of these are required
• Required even if DIS or WQIS is not required

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UDC Section 15.13Stormwater Management Plan

• Required for
• New development
• Redevelopment (demolition or complete removal of
  existing structures or impervious surfaces and
  replacement with new development)

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UDC Section 15.13Stormwater Management Plan

• Exemptions (to submitting a SMP)
• Residential lots of less than ½ acre within
  subdivisions approved on or before Dec. 5, 2007
• All lots in duly authorized subdivisions created
  with an SMP
• Individual lots must comply with SMP for the
  subdivision

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UDC Section 15.13Stormwater Management Plan

• Submit 2 copies of SMP to DPW

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UDC Section 15.17Water Quality Impact Study
WQIS
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UDC Section 15.17Water Quality Impact Study

• Similar to DIS, but for water quality
• Components
• Existing Site Conditions and Location
• Proposed Development Conditions
• Empirically expected pollutants
• Proposed Water Quality Treatment
• Study Conclusions Recommendations

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UDC Section 15.17Water Quality Impact Study

• Required for
• Exemptions (to submitting WQIS)
• Sites with a developed area lt1 acre
• Farming or agricultural activities

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UDC Section 15.17Water Quality Impact Study

• Submit 2 copies of WQIS to DPW

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Questions

• Melissa Guilbeau, AICP
• Urban Transportation Coordinator
• Department of Public Works
• Infrastructure Planning Division
• [phone]
• mguilbeau_at_brgov.com

Jim Ferguson, PE Professional Engineer Department
of Public Works Drainage/Flood Section (225)
389-3196 jferguson_at_brgov.com