Post on 14-Mar-2020
VOLUME 1 REGULATIONS
STORMWATER MANAGEMENT MANUAL
METROPOLITAN GOVERNMENT OF NASHVILLE AND DAVIDSON COUNTY
DEPARTMENT OF WATER AND SEWERAGE SERVICES STORMWATER DIVISION NASHVILLE, TENNESSEE
February 2016
Volume 1 REGULATIONS
STORMWATER MANAGEMENT MANUAL
METROPOLITAN GOVERNMENT OF NASHVILLE AND DAVIDSON COUNTY
Megan Barry, Mayor Scott Potter, Director of Department of Water and Sewerage Services
Metro Water Services Stormwater Division Nashville, Tennessee
February 2016
Volume 1 Table of Contents Page i
February 2016
Metropolitan Nashville - Davidson County Stormwater Management Manual Volume 1 - Regulations
Contents Chapter 1 Introduction ................................................................................................... 1-1 1.1 Background and Purpose ..................................................................... 1-1 1.2 Most Recent Edition ............................................................................ 1-1 1.3 Authorization and Title ........................................................................ 1-2 1.4 Scope .................................................................................................... 1-2 1.5 Language .............................................................................................. 1-2 1.5.1 Rules of Construction .............................................................. 1-2 1.5.2 Definitions................................................................................ 1-3 1.6 Legal Considerations ........................................................................... 1-3 1.6.1 Caveat ...................................................................................... 1-3 1.6.2 Disclaimer of Liability ............................................................. 1-3 1.6.3 Severability .............................................................................. 1-4 1.6.4 Compatibility ........................................................................... 1-4
1.6.5 Saving Provision ...................................................................... 1-4
Chapter 2 Stormwater Management Policy ................................................................... 2-1 2.1 Objectives ............................................................................................ 2-1 2.2 Policy Statements ................................................................................. 2-2 2.3 Stormwater Management Systems ....................................................... 2-4
2.3.1 Minor Systems ......................................................................... 2-5 2.3.2 Major Systems ......................................................................... 2-5
2.4 Stormwater Quantity and Quality Detention ....................................... 2-5 2.5 Other Stormwater Quality Management Practices .............................. 2-6 2.6 Floodplains........................................................................................... 2-6 2.7 Erosion and Sediment Control ............................................................. 2-6 Chapter 3 Administration .............................................................................................. 3-1 3.1 Overview .............................................................................................. 3-1
3.2 Organization ......................................................................................... 3-1
3.2.1 Metro Water Services Stormwater Division ............................ 3-2 3.2.2 Department of Codes Administration ...................................... 3-4 3.2.3 Planning Commission .............................................................. 3-5 3.2.4 Stormwater Management Committee ...................................... 3-5
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Metropolitan Nashville - Davidson County Stormwater Management Manual Volume 1 - Regulations
3.3 Grading and Building Permit Requirements ........................................ 3-5
3.4 Grading Permit Exemptions................................................................. 3-6 3.4.1 Exemption for Approved Subdivision or
PUD Grading Plans ................................................................. 3-7 3.4.2 Exemption for Finish Grading ................................................. 3-7 3.4.3 Exemption for Excavation or Fill ............................................ 3-7 3.4.4 Exemption for Agricultural Practices ...................................... 3-8 3.4.5 Exemption for Maintenance Grading ...................................... 3-8 3.4.6 Exemption for Public Utilities ................................................. 3-9 3.4.7 Exemption for Demolition ....................................................... 3-9 3.4.8 Exemption for Permitted Mining Operations .......................... 3-9
3.5 Exemptions from MWS Building Permit Review ............................... 3-9 3.5.1 Residential Exemptions ......................................................... 3-10 3.5.2 Commercial or Industrial Exemptions ................................... 3-10 3.6 Variance Procedures .......................................................................... 3-10 3.7 Enforcement ....................................................................................... 3-10 3.7.1 Right of Entry ........................................................................ 3-10 3.7.2 Revocation ............................................................................. 3-10 3.7.3 Notice of Violation ................................................................ 3-11 3.7.3.1 Corrective Measures .................................................. 3-11 3.7.3.2 Stop Work Order ........................................................ 3-11 3.7.3.3 Penalties ..................................................................... 3-12 3.7.4 Injunctions ............................................................................. 3-12 3.7.5 Other Enforcement Tools....................................................... 3-12 3.8 Inspections ......................................................................................... 3-13 3.8.1 Permitting............................................................................... 3-13 3.8.2 Construction ........................................................................... 3-13 3.9 As-Built Certifications ....................................................................... 3-14
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Metropolitan Nashville - Davidson County Stormwater Management Manual Volume 1 - Regulations
Chapter 4 Permitting Procedures ................................................................................... 4-1 4.1 Overview .............................................................................................. 4-1 4.2 Application Preparation ....................................................................... 4-1 4.2.1 Pre-Application Meeting.......................................................... 4-1 4.2.2 Required Information and Checklist ........................................ 4-1 4.2.2.1 Grading and Drainage Plans ....................................... 4-2 4.2.2.2 Erosion Prevention and Sediment Control Plans ........ 4-4 4.2.2.3 Post-Construction Stormwater Management Plan ...... 4-5 4.2.2.4 Sinkhole and Drainage Well Information ................... 4-7 4.2.3 Federal and State Permits ......................................................... 4-8 4.2.3.1 U.S. Army Corps of Engineers ................................... 4-8 4.2.3.2 Tennessee Department of Environment and Conservation ............................................................... 4-9 4.3 Application Processing ........................................................................ 4-9 4.3.1 Initial Receipt and Resubmittals .............................................. 4-9 4.3.2 Staff Review and Recommendation ...................................... 4-10 4.3.3 EPSC Professional ................................................................. 4-10 4.3.4 Pre-Construction Meeting ...................................................... 4-11 4.3.5 Installation of Initial Measures .............................................. 4-11 4.3.6 Grading Permit Issuance and Expiration ............................... 4-12 4.3.7 Revisions to Approved Plans ................................................. 4-12 4.4 Construction Procedures .................................................................... 4-13 4.4.1 Posting of Permit ................................................................... 4-13 4.4.2 Effect of Permit ...................................................................... 4-13 4.4.3 Site Inspections ...................................................................... 4-13 4.4.4 EPSC Professional vs. Permit Holder Responsibilities ......... 4-14 Chapter 5 Floodplain Requirements .............................................................................. 5-1 5.1 Zoning Ordinance ................................................................................ 5-1 5.2 Base Flood and Floodway Data ........................................................... 5-1 5.3 General Standards ................................................................................ 5-2 5.4 Preserved Floodplain ........................................................................... 5-3 5.5 Specific Standards................................................................................ 5-3 5.5.1 Residential Construction .......................................................... 5-4 5.5.2 Standards for Manufactured Homes and
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Metropolitan Nashville - Davidson County Stormwater Management Manual Volume 1 - Regulations
Recreational Vehicles .............................................................. 5-4 5.5.3 Non-Residential Construction.................................................. 5-5 5.5.4 Elevated Buildings ................................................................... 5-5 5.5.5 Floodways ................................................................................ 5-6 5.5.6 Floodplain Alterations ............................................................. 5-6 5.5.7 Floodproofing .......................................................................... 5-7
5.6 Standards for Streams Without Established Base Flood Elevations and/or Floodways ............................................................... 5-8 5.7 Subdivision Standards ......................................................................... 5-9 5.8 Nonconforming Uses ........................................................................... 5-9 5.9 Dikes and Floodwalls......................................................................... 5-10 Chapter 6 Technical Guidelines and Criteria ................................................................ 6-1 6.1 Adequate Stormwater Management Systems ...................................... 6-1 6.1.1 Minor Systems ......................................................................... 6-1 6.1.2 Major Systems ......................................................................... 6-2 6.2 Open Channels ..................................................................................... 6-3 6.2.1 Channel Capacity ..................................................................... 6-3 6.2.2 Lined Channels ........................................................................ 6-3 6.2.3 Grassed Channels ..................................................................... 6-3 6.2.4 Easement Width ....................................................................... 6-4 6.3 Storm Pipes and Culverts ..................................................................... 6-4 6.3.1 Conduit Capacity ..................................................................... 6-4 6.3.2 Pressure Flow ........................................................................... 6-4 6.3.3 Easement Width ....................................................................... 6-5 6.3.4 Inlets......................................................................................... 6-6 6.3.5 Culverts .................................................................................... 6-6 6.4 Outlet Protection .................................................................................. 6-6 6.5 Bridges ................................................................................................. 6-6 6.6 Stormwater Quantity Detention ........................................................... 6-6 6.7 Quantity & Quality Stormwater Control Measure (SCM) Maintenance ......................................................................................... 6-7 6.7.1 SCM Maintenance Document .................................................. 6-8 6.7.2 Inspection and Maintenance Responsibilities .......................... 6-8
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Metropolitan Nashville - Davidson County Stormwater Management Manual Volume 1 - Regulations
6.8 Sinkholes and Drainage Wells ............................................................. 6-9 6.9 Water Quality Buffers .......................................................................... 6-9 6.9.1 Identification of Community Waters and Application of Buffers ..................................................................................... 6-9 6.9.2 Buffer Widths ........................................................................ 6-10 6.9.3 Preservation of Water Quality Buffers .................................. 6-13 6.9.4 Maintenance of Water Quality Buffers .................................. 6-13 6.9.5 Uses in the Buffer that are Permissible with Conditions ....... 6-13 6.9.6 Buffer Restoration and Enhancement .................................... 6-14 6.9.6.1 Buffer Restoration and Enhancement Plan Requirements .................................................... 6-14 6.10 Erosion Prevention and Sediment Control Measures ........................ 6-16 6.10.1 Disturbed Areas ..................................................................... 6-16 6.10.2 Final Stabilization .................................................................. 6-17 6.10.3 Protection of Adjacent Properties .......................................... 6-17 6.10.4 Timing and Stabilization of Sediment Trapping Measures ................................................................ 6-17 6.10.5 Sediment Basins ..................................................................... 6-18 6.10.6 Cut and Fill Slopes ................................................................. 6-18 6.10.7 Construction Exits.................................................................. 6-18 6.10.8 Litter and Construction Waste Materials ............................... 6-18 6.10.9 Deficient Performance ........................................................... 6-18 Chapter 7 Post-Construction Water Quality Policies & Procedures ............................. 7-1 7.1 Overview ………………………. ........................................................ 7-1 7.2 Runoff Reduction ................................................................................ 7-2 7.2.1 Redevelopment Credit ............................................................. 7-2 7.2.2 Site Limitations ........................................................................ 7-2 7.3 Pollutant Removal................................................................................ 7-2 7.4 Pre-Approved SCMs ............................................................................ 7-4 7.5 Proprietary SCMs ................................................................................ 7-4 7.5.1 Submittal Requirements ........................................................... 7-5 7.5.2 Design Guidance for Water Quality Treatment ....................... 7-5 7.5.3 Performance Standards for Proprietary SCMs ......................... 7-6 7.5.3.1 Testing Requirements for Proprietary SCMs............... 7-6 7.5.3.1a Field Testing ................................................. 7-6 7.5.3.1b Laboratory Testing ........................................ 7-7
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Metropolitan Nashville - Davidson County Stormwater Management Manual Volume 1 - Regulations
7.6 Safety and Mosquito Control ............................................................... 7-8 7.6.1 Safety Considerations .............................................................. 7-8 7.6.2 Mosquito Control ..................................................................... 7-8 7.7 Stormwater Control Measure Long Term Maintenance ...................... 7-9 Chapter 8 Regulated Residential Infill .......................................................................... 8-1 8.1 Overview ………………………. ........................................................ 8-1 8.2 Definition and Requirement ………………………............................ 8-1 8.2.1 One-Inch Capture Requirement ............................................... 8-2 8.2.2 Alternatives to One-Inch Capture ............................................ 8-2 8.3 Permitting ............................................................................................ 8-3 8.3.1 Pre-Application Meeting.......................................................... 8-3 8.3.2 Required Information and Checklist ........................................ 8-3 8.3.3 Application Processing ............................................................ 8-5 8.3.3.1 Initial Receipt and Resubmittals .................................. 8-5 8.3.3.2 Staff Review and Recommendation ............................ 8-5 8.3.3.3 Installation of Erosion Control Measures .................... 8-5 8.3.3.4 Revisions to Approved Plans ....................................... 8-5 8.4 Construction Procedures ...................................................................... 8-6 8.4.1 Posting of Permit ..................................................................... 8-6 8.4.2 Effect of Permit ........................................................................ 8-6 8.4.3 EPSC Permit Holder Responsibilities ..................................... 8-6 8.4.4 Site Inspections ........................................................................ 8-6 8.4.5 Use and Occupancy ................................................................. 8-6 Appendix A Plan Submittal Information Appendix B Definitions & Acronyms Appendix C Stormwater Control Measure (SCM) Maintenance Document Appendix D Metropolitan Code of Laws §15.64.010 et. seq. and Stormwater Management
Ordinance No.78-840
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February 2016
Metropolitan Nashville - Davidson County Stormwater Management Manual Volume 1 - Regulations
Appendix E Flood Plain Overlay District Ordinance No. 78-843 and Metropolitan Code of Laws §17.36.170 et. seq
Appendix F Stormwater Management Committee Appendix G Memorandum of Understanding Appendix H Regulated Residential Infill Guidance
List of Tables Table 3-1 Administrative Responsibilities for Stormwater Management Activities .......... 3-1 Table 3-2 Common Plat Requirements ............................................................................... 3-3 Table 6-1 Minimum Easement Width for Open Channels .................................................. 6-4 Table 6-2 Minimum Easement Width for Storm Drains ..................................................... 6-5 Table 6-3 Permissible Buffer Impacts, with Conditions ................................................... 6-15 Table 7-1 GIPs for Use in Metro ......................................................................................... 7-3 Table 7-2 PTPs for Use in Metro ........................................................................................ 7-4
List of Figures Figure 2-1 Completed Watershed Master Plans ................................................................... 2-4 Figure 6-1 Buffer Example for Streams with Drainage Area < 100 acres ......................... 6-11 Figure 6-2 Buffer Example for Streams with Drainage Area > 100 acres ......................... 6-12 Figure 6-3 Buffer Example for Streams with Floodways ................................................... 6-12
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