District of Columbia Water and Sewer AuthorityGeorge S. Hawkins, General Manager

September 7, 2014

Rainwater Harvesting: Update on Bioretention at Wangari Gardens

Briefing on:

2

Agenda

Background: Stormwater Runoff & CSOs Background: Plan to Mitigate Flooding DCCR Irving Street Green Infrastructure Project

Purpose Bioretention Locations Benefits Example of Plant Palette Maintenance

DC Water’s Proposed GI Plan

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Background:Comparing Natural vs. Built Environment

Natural Environment(0% Impervious Surface)

Built Environment(75-100% Impervious Surface)

4

Background:Why is stormwater runoff a problem?

Stormwater: Carries trash, excess nutrients (such as nitrogen

and phosphorus), sediment and other pollutants; Impacts waterbodies we use for swimming, fishing and providing drinking water.

5

Background:Separate and Combined Sewer Systems

100% of suburbs67% of D.C.

0% of suburbs33% of D.C.

Including Bloomingdale

2 pipes2 pipes 1 pipe1 pipe

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Background: Northeast Boundary Combined Sewer Drainage Area

The Northeast Boundary Drainage Area has been historically prone to combined sewer overflow (CSO) flooding issues.

The Bloomingdale Drainage Area is located in the northern portion of the Northeast Boundary Drainage Area. Stormwater runoff from this

drainage area contributes to flooding events experienced just north of the Northeast Boundary Trunk Sewer.

Bloomingdale Flood Areas

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Background:Mayor Gray’s Task Force

Person Affiliation

Allen Lew, Co-Chair City Administrator

George Hawkins, Co-Chair DC Water General Manager

Kenyan McDuffie Ward 5 Councilmember

Jim Graham Ward 1 Councilmember

Terry Bellamy Dept of Transportation, Director

Keith Anderson Dept. of the Environment, Interim Director

William Howland Dept. of Public Works, Director

Chris Geldart D.C. Homeland Sec. & Emergency Manag., Director

Nicholas Majett Dept. of Consumer & Regulatory Affairs, Director

Dr. Saul Levin Dept. of Health, Director

William White Dept. of Insurance, Securities & Banking, Director

Eric Goulet Office of Budget and Finance, Budget Director

Serita Sanders Bloomingdale neighborhood representative

Teri Quinn Bloomingdale neighborhood representative

Myla Moss LeDroit Park neighborhood representative

Engineering

Task Force Members

Regulatory

Code Changes

O&M

Public Outreach

McMillan Storage

First St Tunnel

Northeast Boundary

Tunnel

Background: Three-step Infrastructure Solution To Mitigate Flooding

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Irving Street Green Infrastructure and McMillan Stormwater Storage - 4 million gallons

First Street Tunnel – 8 million gallons

Northeast Boundary Tunnel

1

3

2

88

Irving St

Michigan Ave

Rhode Island Ave

Firs

t St.

Nor

th C

ap. S

t

North Capitol Tank & Diversion

Structure

Channing St.

First St Tunnel

Connect Diversion Chamber to First St

Tunnel

Northeast Boundary Tunnel

Bioretention (Green Infrastructure) along

Irving St

First St Diversion Chamber

Legend201420162022

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Irving Street Green Infrastructure Project:Purpose

To help mitigate flooding in the Bloomingdale area, the DC Clean Rivers Irving Street Green Infrastructure Project included: Installation of 14 bioretention

facilities Located along Irving Street

corridor between Michigan Avenue and North Capitol Street

Flooding in Bloomingdale and LeDroit Park

Recently planted bioretention

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Irving Street Green Infrastructure Project: Bioretention Locations

Old Soldiers’ Home

Irving St

Park Place NW

First St

Bioretention Locations (typical)

Washington Hospital Center

N

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Irving Street Green Infrastructure Project:Bioretention Overview What is Bioretention?

A planted filter bed of specialized soil, sand, and stone aggregate

Basins are typically slightly depressed into the surrounding landscape to facilitate runoff flow to the system

Also referred to as rain gardens Formal or informal aesthetic (i.e., street side tree

box vs. naturalized garden)

Purpose/Benefits: Stormwater runoff is slowed, cooled, filtered and

infiltrated Reduced flooding Plants and soil remove contaminants and excess

nutrients

Photo courtesy: Daily Journal of Commerce

Photo courtesy: Dennis Carmichael

~10’ (typ.) ~25’

(typ

.)

Example Bioretention: Street Side Tree Box

Example Bioretention: Naturalized Garden

Photo courtesy: Daily Journal of Commerce

Photo courtesy: Dennis Carmichael

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Irving Street Green Infrastructure Project: Bioretention Overview (Cont.) Additional Benefits:

Provide habitat Establish shade and cooling of

surrounding areas Create community amenity and

enhance green space Improve air quality

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Irving Street Green Infrastructure Project:Typical Bioretention Cross Section

Cross section courtesy: DDOE Stormwater Management Guidebook 2013

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Irving Street Green Infrastructure Project:Bioretention at Wangari Gardens

For Bioretention at Wangari Gardens and along Irving Street: Stormwater collected in the basins will

pond to a depth of up to 12”

Stormwater then filters through a soil media layer which removes contaminants.

Stormwater is then stored in a deep layer of stone and detained there until it is released into the underdrain and ultimately back into the sewer.

Recently planted bioretention

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Grasses: Provide texture and seasonal interest year round.

Perennials: Flowers provide diversity of color during the growing season.

Irving Street Green Infrastructure Project:Plant Selection Examples

Coastal Panic Grass Little Bluestem

Foxglove Beardtongue

Black-eyed Susan

Switchgrass

Photo courtesy: Chhe

Wild Blue Indigo

Photo courtesy: Denis Prevot

Photo courtesy: USDA-NRCS PLANTS Database

Photo courtesy: Chhe

Photo courtesy: D. Gordon E. Robertson

Photo courtesy: Lorax

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Shrubs: Provide texture and form to bioretention areas.

Trees: Provide shade and canopy adjacent to the bioretention facility. Flowers and fall foliage enhance bioretention aesthetics.

Irving Street Green Infrastructure Project: Selection Examples (Cont.)

Redosier Dogwood Northern Bayberry

Eastern Redbud FringetreeBlack Gum

Photo courtesy: Jean-Pol Grandmont

New Jersey Tea

Photo courtesy: H. Zell

Photo courtesy: Greg Hume

Photo courtesy: USDA-NRCS PLANTS Database

Photo courtesy: Chhe

Photo courtesy: Derek Ramsey

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Irving Street Green Infrastructure Project:Bioretention Planting Establishment Example

Bioretention Immediately Following Planting

Bioretention After 1 Growing Season

Bioretention During 2nd Growing Season

Photo courtesy: Seattle Public Utilities

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Irving Street Green Infrastructure Project: Maintenance and Monitoring

DC Water will perform ongoing maintenance to ensure long-term performance of the facilities, such as: Remove trash, sediment and animal waste Weed and prune plants Inspect cleanout pipes and underdrains Inspect and treat vegetation for disease and pest problems

Pre/post construction monitoring will provide data to improve future Green Infrastructure design, construction, operation and maintenance.

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Irving Street Green Infrastructure Project:Signage

Signage has been placed at each bioretention location providing contact information for inquiries.

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Proposed Green Infrastructure Plan:What is Proposed for Potomac and Rock Creek?

$60 M of Green Infrastructure in

Piney Branch

$30 M of Green Infrastructure in CSO

027, 028 and 029

Separate CSO 025 and 026 ($10 M)

For more information on DC Water’s Green Infrastructure Plan, visit: www.dcwater.com/green

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Irving Street Green Infrastructure Project:Contact Information

For more information on the Irving Street Green Infrastructure Project, visit: www.dcwater.com/workzones/projects/irvingstreet

How to reach us: Project Manager: Bethany Bezak (202) 787-4466

Community Outreach: (202) 787-4723