DISTRICT OF COLUMBIA DEPARTMENT OF TRANSPORTATION

GREEN INFRASTRUCTURE STANDARDS

2014

DISTRICT OF COLUMBIA DEPARTMENT OF TRANSPORTATION

GREEN INFRASTRUCTURE STANDARDS

SUPPLEMENT TO DESIGN AND ENGINEERING MANUAL SUPPLEMENT TO STANDARD DRAWINGS

SUPPLEMENT TO STANDARD SPECIFICATION FOR HIGHWAYS AND STRUCTURES

GREEN INFRASTRUCTURE PLANT LIST

GREEN INFRASTRUCTURE MAINTENANCE SCHEDULES

2014

DISTRICT OF COLUMBIA DEPARTMENT OF TRANSPORTATION

TERRY BELLAMY, DIRECTOR

RONALDO T. NICHOLSON, P.E., CHIEF ENGINEER

MUHAMMED KHALID, P.E., DEPUTY CHIEF ENGINEER

RAVINDRA GANVIR, P.E., DEPUTY CHIEF ENGINEER

WASI KHAN, P.E., CHIEF QA/QC DIVISION

Green Infrastructure Standards Development Team DDOT/IPMA/Stormwater Meredith Upchurch, ASLA

Carmen Franks, Ph.D. Alit Balk

Reginald Arno, P.E. Kyle Ohlson, P.E.

DDOT/Urban Forestry John Thomas Sharon Dendy Earl Eutsler

Joseph Burckle DDOT/IPMA/QA-QC

Wasi Khan, P.E. Rezene Medhani, Ph.D., P.E.

Larry Chung Albert Ladipoh DDOT/IPMA

Richard Kenney, P.E. Adil Rizvi, P.E.

District Department Of Environment Rebecca Stack

Steve Saari Greg Hoffmann, P.E., Center for Watershed Protection

A. Morton Thomas & Associates, Inc. Laura Mehiel, P.E.

Don Rissmeyer, P.E. Steve Torgerson, ASLA Larry G. Trout, Jr., P.E.

Robert Pine, FASLA, Pine & Swallow

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TABLE OF CONTENTS

Supplement to Design and Engineering Manual Chapter 2 Project Development

2.3 Project Design Requirements 2.3.10 Soil Erosion and Sediment Control and Stormwater Management 2.3.11 Submittals

2.3.11.1 Preliminary Plan Submittal 30% Review 2.3.11.1.9 Stormwater Management Plan Submission at 30% Design Phase 2.3.11.2 Intermediate (Pre-Final) Plan Submittal 65% Review 2.3.11.2.9 Stormwater Management Plan Submission at 65% Design Phase 2.3.11.3 Final Construction Plans, Specifications, and Cost Estimates Final Review

2.4 Preparation of Drawings 2.4.3 Description and Contents of Drawings

2.4.3.16 Landscape and Planting Plans 2.4.3.37 Stormwater Management Plan and BMP Design Submittal Requirements

Chapter 33 Roadway Drainage 33.14 Green Infrastructure/Low Impact Development Stormwater Management

Chapter 47 Landscape Design Criteria 47.7 Tree Space Design 47.8 Planting Guidance for Vegetated Stormwater Systems

Supplement to Standard Drawings Permeable Pavement Series 621.01 Pervious Concrete Pavement (Roadway and Alley) 621.02 Pervious Concrete Sidewalk 621.03 Porous Asphalt Pavement (Roadway and Alley) 621.04 Porous Asphalt Sidewalk 621.05 Permeable Interlocking Unit Paver Pavement (Roadway and Alley) 621.06 Permeable Paver Sidewalk 621.10 Permeable Pavement Elevation - 1 621.11 Permeable Pavement Elevation 2 621.12 Permeable Pavement Edge Restraint

Bioretention Series 621.20 Bioretention in Open Area 621.21 Bioswale Adjacent to Roadway 621.22 Bioretention Planter Adjacent to Roadway 1 No Step Out Zone 621.23 Bioretention Planter Adjacent to Roadway 2 With Step Out Zone

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621.24 Curb Extension In-Planting Strip Bioretention 621.25 Curb Extension In-Street Bioretention 621.30 Bioretention Facility Street Side Edge Treatment -1 621.31 Bioretention Facility Street Side Edge Treatment -2 621.32 Bioretention Facility Sidewalk Side Edge Treatment 621.40 Inlet and Outlet for Curb Extension Bioretention 621.41 Curb Cut with Splash Pad - 1 621.42 Curb Cut with Splash Pad - 2 621.43 Curb Cut Metal Trench Drain Cover - 1 621.44 Curb Cut Metal Trench Drain Cover - 2 621.45 Metal Plate over Curb Cut

Flow Conveyance Series 621.50 Overflow Riser with Beehive Grate 621.51 Stormwater Facility Underdrain Pipe Risers 621.52 Stormwater Facility Underdrain Bedding and Catch Basin Connection

Check Dam Series 621.60 Concrete Check Dam 621.61 Rock Check Dams 621.62 Plastic Lumber Check Dam 621.63 Acrylic Sheet Check Dam 621.64 Alternate Permeable Pavement Check Dams

Tree Space Series 621.70 Structural Soil Under Sidewalk Covered Tree Space 621.71 Structural Soil Under Sidewalk Continuous Open Tree Space 621.72 Structural Soil Under Sidewalk Confined Open Tree Space 621.73 Structural Soil Under Covered Tree Space Only 621.74 Tree Space Covered Soil Volume Subsurface Drainage Options 621.75 Covered Soil Volume 1 Pervious Cover or Impervious Cover with Linear Grate 621.76 Covered Soil Volume 2 Impervious Cover with Catch Basin 621.77 Tree Space Grate Catch Basin

Supplement to Standard Specifications for Highways and Structures 621.01 Aggregates for Stormwater Management 621.02 Geosynthetics for Stormwater Management 621.03 Underdrains for Stormwater Facilities 621.04 Pervious Concrete Pavement 621.05 Porous Asphalt Pavement 621.06 Permeable Unit Paver Pavement 621.07 Porous Flexible Pavement

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621.08 Porous Grass Pavement 621.09 Bioretention, Plant Bed, Lawn and Sand Based Structural Soils 621.10 Triple Shredded Hardwood Mulch 621.11 Curb Cut Metal Trench Drain Cover 621.12 Domed Overflow Riser 621.13 Check Dams for Stormwater Facilities 621.14 Sidewalk Linear Slot Drain 621.15 Tree Space Grate Catch Basin 621.16 CU Soil 621.17 Lightweight Aggregate 621.18 Structural Cells for Soil Rooting Volume

Green Infrastructure Plant List Plants for use in Bioretention Trees for use in Public Space

Green Infrastructure Maintenance Schedules Permeable Pavement Bioretention Tree Space

DISTRICT OF COLUMBIA DEPARTMENT OF TRANSPORTATION

GREEN INFRASTRUCTURE STANDARDS

SUPPLEMENT TO DESIGN AND ENGINEERING MANUAL

2014

SUPPLEMENT TO DDOT DESIGN AND ENGINEERING MANUAL

D-1

District of Columbia Department of Transportation Design and Engineering Manual The sections provided in this Standards Manual are to supplement the existing Design and Engineering Manual. No sections of the current manual are deleted and no text is modified. All sections herein are to follow any existing sections and text sequentially. Supplement To: CHAPTER 2

PROJECT DEVELOPMENT

2.3 Project Design Requirements 2.3.10 Soil Erosion and Sediment Control and Stormwater Management

2.3.10.1 Stormwater Management Permit Requirements- Designing to the Maximum Extent Practicable

Projects within the Public Right of Way are required to implement stormwater retention in accordance with District Stormwater regulations to the Maximum Extent Practicable (MEP). This process must be a serious attempt to comply, considering every opportunity to achieve the full retention of the regulated stormwater volume. Construction projects in the Right of Way are faced with a multitude of unique site constraints that vary widely. Limited space outside of the roadway restricts opportunities for infiltration and evapotranspiration, and in many cases the width of the roadway cannot be reduced to create additional space. The specific steps that must be explored for MEP design are stipulated in the DDOE Stormwater Guidebook, and include:

Identify Drainage Areas and Calculate Stormwater Retention Volume (SWRv) Evaluate Infiltration Demonstrate Full Consideration of Opportunities with Existing Infrastructure Demonstrate Full Consideration of Land Cover Conversions and Optimum BMP

Placement Size BMPs Address Drainage Areas where Zero-Retention Practices are Installed (i.e. no

retention is achieved)

The DDOE Stormwater Guidebook defines the applicability of the design steps described below to DDOT Public Right of Way projects, and/or to parcel development projects that reconstruct the adjacent existing Public Right of Way as portion of the project (Type 1 and Type 2 projects, respectively).

SUPPLEMENT TO DDOT DESIGN AND ENGINEERING MANUAL

D-2

2.3.10.2 Stormwater Management Submissions

Stormwater Management Plan (SWMP) submissions will be made with the 30%, 65%, 90%, and Final (100%) Design packages. The SWMP will contain a stormwater management map (SMM), MEP Worksheet, and Project Narrative as further in the Design Process section.

The submissions will include increasingly more detail commensurate with the design stage. The SWMP is first submitted at the DCRA Permit Intake Center with a Building Permit application at 30% design. At DCRA, the SWMP is given to the DDOE technician for further detailed plan review. Each design phase SWMP will be submitted to the DDOE Technician at the DCRA Permit Intake Center. The timing of the submission should be within 2 weeks of the design plan milestone submission to DDOT. The submission will be reviewed by the DDOT project manager prior to submission at the Intake Center. DDOE plan review may take 10-30 business days.

2.3.10.3 Design Process for MEP

Prior to Project Design:

Before the project reaches the design stage, the following items will be identified and incorporated into the Designers scope of work:

a. Level of Disturbance: the level of disturbance will determine whether or not the retention regulation applies to the project.

b. Ownership of Land Adjacent to Right of Way: Projects must identify public lands and public rights of way adjacent to the projects limit of disturbance. DDOT will consult with adjacent public property owners and managers to evaluate opportunities to direct stormwater runoff from the project drainage area to adjacent public lands. (This step applies only to DDOT projects, not to parcel projects which include construction within the Right of Way).

c. Feasibility to Use Public Parking Zone: DDOT will define whether or not the Public Parking areas (between the sidewa