- Introduction
- Ch. 1 Stormwater Management Requirements
- Ch. 2 Submission, Review, and Approval Procedures
- Ch. 3 Site Design and Stormwater Management Integration
- Ch. 4 Stormwater Management Practice Guidance
- Ch. 5 Construction Guidance
- Ch. 6 Post-Construction and Operations and Maintenance Guidance
- Appendices
- Download
- Back to Chapters
- Manual Organization and Purpose
- Stormwater Regulations
- Private Development Services
- Stormwater Billing and Incentives
- Stormwater Management in Philadelphia
- Applicability and Submission Process
- Preferred Design Approach
- Back to Chapters
- 1.0 Introduction
- 1.1 Applicability Factors
- 1.2 Stormwater Regulations
- 1.3 Stormwater Retrofits
- Back to Chapter 1
- 1.2.1 Post-Construction Stormwater Management Requirements
- 1.2.2 Erosion and Sediment Control Requirement
- Back to Chapter 1
- 1.3.1 Retrofit Project Applicability and Initiation
- 1.3.2 Retrofit Project Requirements and Guidance
- Back to Chapters
- 2.0 Introduction
- 2.1 Existing Resources and Site Analysis
- 2.2 Review Paths
- 2.3 Review Phases
- 2.4 Expedited Post-Construction Stormwater Management Plan Reviews
- 2.5 PWD’s Development Review Process
- 2.6 PWD’s Role in Philadelphia's Development Process
- 2.7 PWD and Pennsylvania Department of Environmental Protection
- Back to Chapter 2
- 2.2.1 Development Compliance Review Path
- 2.2.2 Development Exemption Review Path
- 2.2.3 Demolition Review Path
- 2.2.4 Stormwater Retrofit Review Path
- Back to Chapter 2
- 2.3.1 Development Compliance Review Path
- 2.3.2 Development Exemption Review Path
- 2.3.3 Demolition Review Path
- 2.3.4 Stormwater Retrofit Review Path
- Back to Chapter 2
- 2.4.1 Disconnection Green Review
- 2.4.2 Surface Green Review
- 2.4.3 Expedited PCSMP Review Process
- Back to Chapter 2
- 2.7.1 National Pollutant Discharge Elimination System Permits
- 2.7.2 Other PA DEP Requirements
- Back to Chapters
- 3.0 Introduction
- 3.1 Site Assessment and Stormwater Management Strategies
- 3.2 Stormwater Management Design
- 3.3 Infiltration Testing and Soil Assessment for SMP Design
- 3.4 How To Show Compliance
- 3.5 Integrated Stormwater Management Examples
- Back to Chapter 3
- 3.0.1 How to Use This Chapter
- 3.0.2 Integrated Site and Stormwater Management Assessment and Design Process Overview
- 3.0.3 Interactions between Design Strategies, Stormwater Regulations, and Review Paths
- Back to Chapter 3
- 3.1.1 Background Site Factors and Site Factors Inventory
- 3.1.2 Site Factors Analysis
- 3.1.3 Integrated Design Approach
- 3.1.4 Non-Structural Design
- 3.1.5 Disconnected Impervious Cover
- 3.1.6 SMP Functions
- 3.1.7 Pollutant- Reducing Practices and Roof Runoff Isolation
- 3.1.8 How to Use SMPs to Comply with the Regulations
- Back to Chapter 3
- 3.2.1 Major SMP Types
- 3.2.2 SMP Hierarchy and Selection Process
- 3.2.3 Placing SMPs in Series
- 3.2.4 Stormwater Management Banking and Trading
- 3.2.5 SMP Design Guidance and General Requirements
- 3.2.6 Loading Ratio Requirements
- 3.2.7 Planting and Vegetation Guidance
- 3.2.8 Operations and Maintenance
- Back to Chapter 3
- 3.3.1 Infiltration Testing and Soil Characterization Plan Development
- 3.3.2 Soil Characterization Requirements
- 3.3.3 Infiltration Testing Requirements
- 3.3.4 Soil Characterization Procedures
- 3.3.5 Infiltration Testing Procedures
- 3.3.6 Evaluation of Infiltration Testing Results
- Back to Chapter 3
- 3.4.1 Regulatory Compliance Documentation Requirements
- 3.4.2 Storm Sewer Design Requirements
- 3.4.3 Calculation Methods and Design Tools
- Back to Chapter 3
- 3.5.1 Commercial Office Building Development
- 3.5.2 Residential Multi-Family Development
- 3.5.3 Full Build-Out
- 3.5.4 Trails
- 3.5.5 Athletic Fields
- 3.5.6 Streets
- Back to Chapters
- 4.0 Introduction
- 4.1 Bioinfiltration/ Bioretention
- 4.2 Porous Pavement
- 4.3 Green Roofs
- 4.4 Subsurface Infiltration
- 4.5 Cisterns
- 4.6 Blue Roofs
- 4.7 Ponds and Wet Basins
- 4.8 Subsurface Detention
- 4.9 Media Filters
- 4.10 Pretreatment
- 4.11 Inlet Controls
- 4.12 Outlet Controls
- Back to Chapter 4
- 4.1.1 Bioinfiltration/ Bioretention Introduction
- 4.1.2 Bioinfiltration/ Bioretention Components
- 4.1.3 Bioinfiltration/ Bioretention Design Standards
- 4.1.4 Bioinfiltration/ Bioretention Material Standards
- 4.1.5 Bioinfiltration/ Bioretention Construction Guidance
- 4.1.6 Bioinfiltration/ Bioretention Maintenance Guidance
- Back to Chapter 4
- 4.2.1 Porous Pavement Introduction
- 4.2.2 Porous Pavement Components
- 4.2.3 Porous Pavement Design Standards
- 4.2.4 Porous Pavement Material Standards
- 4.2.5 Porous Pavement Construction Guidance
- 4.2.6 Porous Pavement Maintenance Guidance
- Back to Chapter 4
- 4.3.1 Green Roof Introduction
- 4.3.2 Green Roof Components
- 4.3.3 Green Roof Design Standards
- 4.3.4 Green Roof Material Standards
- 4.3.5 Green Roof Construction Guidance
- 4.3.6 Green Roof Maintenance Guidance
- Back to Chapter 4
- 4.4.1 Subsurface Infiltration Introduction
- 4.4.2 Subsurface Infiltration Components
- 4.4.3 Subsurface Infiltration Design Standards
- 4.4.4 Subsurface Infiltration Material Standards
- 4.4.5 Subsurface Infiltration Construction Guidance
- 4.4.6 Subsurface Infiltration Maintenance Guidance
- Back to Chapter 4
- 4.5.1 Cistern Introduction
- 4.5.2 Cistern Components
- 4.5.3 Cistern Design Standards
- 4.5.4 Cistern Material Standards
- 4.5.5 Cistern Construction Guidance
- 4.5.6 Cistern Maintenance Guidance
- Back to Chapter 4
- 4.6.1 Blue Roof Introduction
- 4.6.2 Blue Roof Components
- 4.6.3 Blue Roof Design Standards
- 4.6.4 Blue Roof Material Standards
- 4.6.5 Blue Roof Construction Guidance
- 4.6.6 Blue Roof Maintenance Guidance
- Back to Chapter 4
- 4.7.1 Pond and Wet Basin Introduction
- 4.7.2 Pond and Wet Basin Components
- 4.7.3 Pond and Wet Basin Design Standards
- 4.7.4 Pond and Wet Basin Material Standards
- 4.7.5 Pond and Wet Basin Construction Guidance
- 4.7.6 Pond and Wet Basin Maintenance Guidance
- Back to Chapter 4
- 4.8.1 Subsurface Detention Introduction
- 4.8.2 Subsurface Detention Components
- 4.8.3 Subsurface Detention Design Standards
- 4.8.4 Subsurface Detention Material Standards
- 4.8.5 Subsurface Detention Construction Guidance
- 4.8.6 Subsurface Detention Maintenance Guidance
- Back to Chapter 4
- 4.9.1 Media Filter Introduction
- 4.9.2 Media Filter Components
- 4.9.3 Media Filter Design Standards
- 4.9.4 Media Filter Material Standards
- 4.9.5 Media Filter Construction Guidance
- 4.9.6 Media Filter Maintenance Guidance
- Back to Chapter 4
- 4.10.1 Pretreatment Introduction
- 4.10.2 Filter Strips
- 4.10.3 Forebays
- 4.10.4 Swales
- Back to Chapter 4
- 4.11.1 Inlet Control Introduction
- 4.11.2 Flow Splitters
- 4.11.3 Curbless Design/Curb Openings
- 4.11.4 Energy Dissipaters
- 4.11.5 Inlets
- Back to Chapter 4
- 4.12.1 Outlet Control Introduction
- 4.12.2 Orifices
- 4.12.3 Weirs
- 4.12.4 Risers
- 4.12.5 Underdrains
- 4.12.6 Level Spreaders
- 4.12.7 Impervious Liners
- 4.12.8 Micro Siphon Drain Belts
- 4.12.9 Low Flow Devices
- Back to Chapters
- 5.0 Introduction
- 5.1 Construction Inspection
- 5.2 Common Construction Issues
- 5.3 Construction Documentation
- Back to Chapter 5
- 5.1.1 Coordinating Inspections with Other PWD Units
- 5.1.2 Preconstruction Processes
- 5.1.3 Construction Processes
- 5.1.4 Final Inspection
- 5.1.5 Post-Construction Submissions
- Back to Chapter 5
- 5.2.1 Erosion and Sediment-Related Construction Issues
- 5.2.2 Stormwater Management Practice-Related Construction Issues
- Back to Chapters
- 6.0 Introduction
- 6.1 Operations and Maintenance
- 6.2 Stormwater Management Practice Inspection Guidance
- 6.3 Stormwater Credits Program
- Back to Chapter 6
- 6.1.1 Maintenance Requirements for Property Owners
- 6.1.2 Operations and Maintenance Agreements
- Back to Chapters
- Appendix Index
- A. Glossary
- B. Abbreviations
- C. PWD Stormwater Regulations
- D. Watershed Maps
- E. Plan and Report Checklists
- F. Design Guidance Checklists
- G. SMP Maintenance Guide Documents
- H. Infiltration Testing Log
- I. Landscape Guidance
- J. Construction Certification Package
- K. Record Drawing Sample
- L. Standard Details
- Back to Appendices
- Table E-1: General Plan Sheet Requirements
- Table E-2: Existing Conditions Plan Requirements
- Table E-3: Conceptual Stormwater Management Plan Requirements
- Table E-4: Erosion and Sediment Control Plan Requirements
- Table E-5: Standard Erosion and Sediment Control Notes
- Table E-6: Standard Sequence of Construction Notes
- Table E-7: Post-Construction Stormwater Management Plan Report Requirements
- Table E-8: Record Drawing Requirements
- Back to Appendices
- F.1 Stormwater Regulation Compliance
- F.2 Post-Construction Stormwater Management Plan
- F.3 Erosion and Sediment Control
- F.4 Disconnected Impervious Cover
- F.5 Infiltration Testing and Soil Assessment
- F.6 Hydrologic Model and Calculation Methods
- F.7 Bioinfiltration/ Bioretention
- F.8 Porous Pavement
- F.9 Green Roofs
- F.10 Subsurface Infiltration
- F.11 Cisterns
- F.12 Blue Roofs
- F.13 Ponds and Wet Basins
- F.14 Subsurface Detention
- F.15 Media Filters
- F.16 Pretreatment
- F.17 Inlet Controls
- F.18 Outlet Controls
F.3 Erosion and Sediment Control
F.3.1 E&S Plans
- Verify that the E&S Plans meet all of the E&S Plan requirements listed in Appendix E, Table E-4. [Section 2.3.1]
- Verify that the E&S Plans include all standard E&S notes listed in Appendix E, Table E-5. [Section 2.3.1]
- Verify that the boundaries of, and total area encompassed by, the limit of earth disturbance are clearly indicated on the plans and that the area is consistent with the area provided on the PWD Stormwater Plan Review Online Technical Worksheet. [Section 2.3.1; Appendix E, Table E-4]
- Verify that the limit of disturbance includes all off-site storm and utility connections. [Appendix E, Table E-4]
- If a PA DEP NPDES Permit has not been applied for, verify that the limit of disturbance remains less than one acre. Site disturbance limits within approximately 10% of one acre are more likely to reach or exceed one acre during construction. Therefore, PWD recommends applying for a PA DEP NPDES Permit in such a situation. Should a site inspection reveal more than one acre of earth disturbance, the site will be required to apply for a PA DEP NPDES Permit. The site will be subject to the enforcement actions outlined in the Stormwater Regulations until the applicant receives an approved NPDES Permit. [Section 2.3.1]
- Verify that soil compaction has been minimized, even in areas not proposed for infiltration SMPs, to the extent practicable. [Section 5.2.2]
- Verify that the E&S Plans propose, in plan view, the location of any orange construction fence or silt fence proposed to protect and mark infiltration areas. [Section 5.2.2]
- Verify that inlet protection is provided for all inlets owned by PWD that are located within one block of the project site on the plans. [Appendix E, Table E-5]
- Verify that the E&S Plans propose silt fence and/or compost filter sock along all downward-sloping areas of the project site’s perimeter. [Appendix E, Table E-4]
- Verify that any proposed stockpile locations are clearly labeled on the plans. [Appendix E, Table E-4]
- Verify that the E&S Plans propose silt fence surrounding any proposed stockpile areas. [Appendix E, Table E-4]
- Verify the dimensions of the rock construction entrance. The minimum length is 50 feet, and the minimum width is 20 feet. [Appendix E, Table E-4]
- Verify that the rock construction entrance is not located on top of any proposed infiltration practice. It may be necessary to phase the erosion and sediment control plan to avoid compaction of the infiltration area. [Section 5.2.2]
- Verify that the E&S Plans propose tree protection fencing around existing trees that are proposed to remain and be used for tree disconnection credit. [Appendix E, Table E-4]
- When compost filter socks are placed on paved surfaces, verify that the E&S Plans indicate that some objects of considerable mass (i.e. concrete blocks, sand bags, etc.) are to be used immediately downslope of the socks (at the same intervals as recommended by the sock manufacturer for stakes) in order to help hold them in place. [Appendix E, Table E-5]
- Verify that the E&S Plans propose a concrete washout station. [Appendix E, Table E-4]
- Verify that the E&S Plans propose dust control measures appropriate to the project. Refer to the City of Philadelphia Department of Public Health Air Management Services Construction/Demolition/Earthworks Dust Control Requirements FAQ for guidance. [Appendix E, Table E-4]
F.3.2 Sequence of Construction
- Verify that the E&S Plans include all standard sequence of construction notes listed in Appendix E, Table E-6. [Section 2.3.1]
- Verify that sequences of construction are provided for both overall construction and the construction of each proposed individual SMP. [Section 2.3.1]
- Verify that the sequence of construction properly identifies all stages of SMP construction for which a registered professional must document the specific elevations and measurements found on the SMP Construction Certification Form(s) within the Construction Certification Package. [Section 5.3.1]
- For soil amendments, verify that the following sequence of construction is clearly noted on the plans. [Section 3.3.6]
- Excavate two feet below the proposed infiltration bed invert elevation.
- Manually grade and scarify the existing soil surface. The bottom of the infiltration bed shall be at a level grade. The existing subgrade shall not be compacted or subject to excessive construction equipment.
- Place geotextile filter fabric immediately after approval of subgrade preparation in accordance with manufacturer’s standards and recommendations.
- Amend in-situ soil. [Provide instructions for amending the in-situ soil. Soil amendment media can include compost, mulch, manures, sand, and manufactured microbial solutions.] The project geotechnical engineer should be on-site to observe installation of soil amendments.
- Place two feet of amended soil across the entire cross-section of the infiltration bed. Lightly compact each layer with light equipment, keeping equipment movement over storage bed subgrades to a minimum.
- Perform infiltration testing of the amended soil layer. A minimum of three infiltration tests must be performed within the amended soil layer. The procedure used must be the double-ring infiltrometer test, soil sampling and characterization are also required, and all must be in compliance with the current Philadelphia Stormwater Management Guidance Manual. Prior to infiltration testing, PWD must be called (office: 215-685-6387) to schedule an observation. The engineer must provide a signed and sealed Geotechnical Report. All information must be submitted to PWD for review and approval before proceeding with construction. If soil amendments are installed, and the tested infiltration rate is determined to be outside of the PWD allowable range of 0.4 to ten inches per hour or varies significantly from the design infiltration rate, additional soil amendments and/or a system redesign will be required. Once the infiltration test results are reviewed and determined by PWD to be acceptable, proceed with installation of the infiltration practice.
- Soil amendments shall not be compacted or subject to excessive construction prior to the placement of geotextile and stone bed.
- Place geotextile and infiltration bed aggregate immediately after approval of soil amendment preparation to prevent accumulation of debris and sediment. Prevent runoff and sediment from entering the storage bed during the placement of the geotextile and aggregate bed.
- Place geotextile in accordance with manufacturer’s standards and recommendations. Adjacent strips of filter fabric shall overlap a minimum of 16 inches. Fabric shall be secured at least four feet outside of bed.
- Install aggregate course in lifts of six to eight inches. Lightly compact each layer with light equipment, keeping equipment movement over storage bed subgrades to a minimum. If proposed, install storage structures (e.g., pipes, arches, crates, etc.) during stone bed placement. Install aggregate to grades indicated on the drawings.
- Complete surface grading above subsurface infiltration system, using suitable equipment to avoid excess compaction.
F.3.3 E&S Details
- Verify that an inlet protection detail is provided on the plans. Verify that appropriate inlet protection details are provided for inlets in the public right-of-way. For roadways maintenance purposes, PWD does not allow inlet protection that includes stone or berms to be used in the public right-of-way. [Section 2.3.1; Appendix E, Table E-4]
- Verify that details for silt fence and/or compost filter socks are provided on the plans. Refer to Standard Details #4-1 and 4-7 through 4-10 of the PA DEP Erosion and Sediment Pollution Control Program Manual (2012 or latest) for guidance. [Section 2.3.1; Appendix E, Table E-4]
- Verify that a rock filter outlet detail is provided on the plans. Refer to Standard Detail #4-6 of the PA DEP Erosion and Sediment Pollution Control Program Manual (2012 or latest) for guidance. [Section 2.3.1; Appendix E, Table E-4]
- Verify that a rock construction entrance detail is provided on the plans. Refer to Standard Details #3-1 and 3-2 of the PA DEP Erosion and Sediment Pollution Control Program Manual (2012 or latest) for guidance. [Section 2.3.1; Appendix E, Table E-4]
- Verify that a pumped water filter bag detail is provided on the plans. Refer to Standard Detail #3-16 of the PA DEP Erosion and Sediment Pollution Control Program Manual (2012 or latest) for guidance. [Section 2.3.1; Appendix E, Table E-4]
- Verify that a concrete washout station detail is provided on the plans. Refer to Standard Detail #3-18 of the PA DEP Erosion and Sediment Pollution Control Program Manual (2012 or latest) for guidance. [Section 2.3.1; Appendix E, Table E-4]
- If riprap is proposed, verify that the E&S Plans include a riprap detail which shows that geotextile or filter stone is provided for erosion protection of the soil beneath the riprap. Refer to Standard Details #9-1 through 9-3 of the PA DEP Erosion and Sediment Pollution Control Program Manual (2012 or latest) for guidance. [Appendix E, Table E-4]