Post on 02-Apr-2015
transcript
District of Columbia Water and Sewer AuthorityGeorge S. Hawkins, General Manager
September 7, 2014
Rainwater Harvesting: Update on Bioretention at Wangari Gardens
Briefing on:
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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)
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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.
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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
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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