The Benefits and Challenges
Associated with Green Infrastructure
Practices
Thomas M. Evans ASLA, LEED AP
Regional Green Infrastructure Design Services Director
OWEA Technical Conference, June 20, 2013
Agenda
• Overview of Green Infrastructure Practices
• Critical GI Practices for Stormwater, Floodplain and
CSO Applications
• Case Studies
• GI Benefits, Challenges, Lessons Learned
• Questions
Green Infrastructure Practices
Applicable to Stormwater, Floodplain
Management, and CSO Control
• Stormwater Wetlands
• Stream Restoration
• Green Streets, Bioinfiltration
• Demonstration Projects
Green Infrastructure Benefits Functional/Measurable Values
- Water Quality Improvement, Sediment and Nutrient trapping,
- Flood relief, Floodplain reduction
- Runoff Reduction
- CSO Reduction
- Aquatic and terrestrial habitat restoration/enhancement
Intangible Values
- Neighborhood Beautification
- Increased Real Estate Values
- Parks, Open Space, Greenway/Trail linkages
- Public Education
- Public Health Benefits
Green Infrastructure Challenges - Opportunity Sites, Land Availability
- Need more Monitoring data on Cost Effectiveness
- Interagency - Interdepartmental Collaboration
- Need more Quantification of Intangible Community Benefits
- Modeling to Optimize Benefits
- Public Education
Green Infrastructure must FIT the Community
- Ecological Conditions:
Soils, Groundwater, Rainfall Patterns, habitat,
- Available Land:
Parks, Right of Way, Stream Easements, Public Space, Vacant, Distressed Properties, Land Banks,
- Work with Partnerships:
Redevelopment, DOTs, Parks, Schools, Community Development Corporations
Stormwater Wetlands
for Quantity/Quality Control Wetland Conservation Area, New Albany, Ohio
Stormwater Wetland for Quantity/Quality
Control Wetland Conservation Area, New Albany, Ohio
Stormwater Wetland
Design Elements
• Forebay for sediment
trapping
• Circuitous Wetland for
nutrient uptake and
pollutant breakdown
Stormwater Wetland for Quantity/Quality
Control Wetland Conservation Area, New Albany, Ohio
• Serves as a Community
Open Space
Centerpiece
• Serves as a School
Land Lab
• Enhances Land Values
Pollutant Removal Capabilities of
Stormwater Wetlands
Pollutant Removal Rates (%)
Total Suspended Solids 75%
Total Phosphorous 45%
Total Nitrogen 25%
Organic Carbon 15%
Lead 75%
Zinc 50%
Bacteria 2 log reduction
From: Design of Stormwater Wetlands
Metropolitan Washington Council of Gov’ts
Benefits: Wetland Conservation Area, New Albany, Ohio
- 30 acre wetland park containing 13 acres of wetland replacement
- 40% Reduction in Peak stormwater discharges
- Stormwater filtration functions optimized thru physical and biological processes.
- High visibility, Gateway to amenity to 5000 acre new development
- Habitat diversity includes Open water wetlands, forested wetlands
- Educational land lab to adjacent Middle/High School complex supports Vocational Ed program serving 16 school districts.
- Property values of adjacent properties increased 10-25%
- $1M Funding Partnership with ODOT for Wetland Mitigation.
Challenges: Wetland Conservation Area, New Albany, Ohio
- Cost of land
- Identifying Opportunity Sites
- Permitting
- Hydrology uncertainty, backup wells,
- Vegetation Establishment Uncertainty
- Invasive species
Stream Restoration
for Flood Relief and Habitat Enhancement Lake County, Ohio Stormwater Management Dept.
Kellogg Creek Restoration
Stream Restoration
for Flood Relief, and Habitat Enhancement Lake County, Ohio Stormwater Management Dept.
Kellogg Creek Restoration
Floodplain Restoration in Narrow Stream Easement
Stream Restoration for Flood Relief and Habitat
Enhancement Lake County, Ohio Stormwater Management Dept.
Kellogg Creek Restoration
Before, Channelized Stream
After, Floodplain Restoration
Lowered flood elevations by 2’,
Removed Structures from Floodplain
Benefits: Kellogg Creek Restoration, Lake County, Ohio
- 2200 Lineal Feet of Stream Restoration
- 1-2’ Foot Flood Elevation Reduction
- Reduced peak discharges by 25%
- Removed 5 structures from Floodplain
- Only had 20’-40’ Easement
- First Stream restoration in Lake County
- Effective Public Outreach resulted in 12 donated stream easements
- Colorful native plantings
- $ 600,000 Project Cost = Construction + Engineering
Green Streets: Philadelphia/PennDOT I-95/Girard Street
• $400M I-95 and Urban Arterial Reconstruction along the Delaware River
• 6 phases of construction
• Incorporating extensive G I on I-95 and Urban Roadways.
• One of the Largest G I installations in Philadelphia with Roadway runoff
• Partnership between PennDOT and Philadelphia Water Department
Green Streets: Philadelphia/PennDOT I-95/Girard St. Phase 1
Phase 1 – Relocates 1 mile of Richmond Street and includes 93 stormwater tree vaults, median bioswales, and raingardens. Phila. Water Dept. to maintain this city street.
Goal for capture with the stormwater tree vaults is 30% of a 1" storm
Phase 1 Awarded for Construction 2011 - $91 million
Green Streets: Philadelphia/PennDOT I-95, Phase 2
Phase 2 Highlights: - Roadside bioswales along 6 urban blocks of I-95 30,000 SF of bioswales BMPs required by permit Extensive landscape buffering requested by public
Green Streets: Philadelphia/PennDOT I-95, Phase 2
Green Streets: Philadelphia/PennDOT I-95/Girard St.
Phase 2 – Under Design. Over 30,000 square feet of bioswales for water
quality for 12 lanes of highway. Still discharges to CSO – captures
and treats first 1” of rain. PennDOT to maintain highway bioswales in
ROW.
Phase 3 through 5 – Under Design. Over 20 acres of GI collecting runoff
from new 1 mile, 12 lane highway. Includes stormwater wetlands,
infiltration basins, raingardens, bioretention areas, and pervious
pavement. GI will intertwine with new off road trail and new parking
and recreational areas. Includes sewer separation to Delaware River.
PennDOT and consultant working with community groups, Delaware River
Waterfront, Phila. Parks and Phila. Water Dept. for long term
maintenance.
Challenges: I-95 Green Infrastructure
- Public wanted sustainability, buffering, public spaces
- Interagency cooperation required between PennDOT and PWD.
- Maintenance agreement with Community Groups
- Compliance with plans and specifications is spotty,
Pervious Pavers Parking Lane Tree Box Application
Challenges:
1. Not a one size fits all approach
2. In larger basin areas, more green is req’d so
capital costs are close to gray storage solutions.
20-yr lifecycle costs however are lower.
3. Community buy-in is critical
4. Monitoring (in combined system and on individual
practices) will provide important verification
5. Down spout disconnection program will be critical
in order to route Stormwater from impervious
surfaces
CLEAN, GREEN, GROWING COMMUNITY
Residential and Commercial Green Infrastructure Demonstrations
Mayfield Heights City Hall Green Infrastructure
Demonstration Project
Forested Parking Lot Demonstration
Mayfield Heights City Hall Green Infrastructure
Demonstration Project
Before After
Commercial Parking Lot Demonstration
Mayfield Heights City Hall Green Infrastructure
Demonstration Project
Pervious Concrete
Before After
Mayfield Heights City Hall Green Infrastructure
Demonstration Project
Residential Downspout Disconnection Demonstration
Benefits: Mayfield Heights City Hall Green Infrastructure
Demonstration Project
- Demonstrates Residential Downspout Disconnection, flow to raingarden
- Demonstrates commercial parking lot pervious pavement
- Demonstrates forested parking lot
- High Visibility, Publicly Accessible Location
Challenges: Mayfield Heights City Hall Green Infrastructure
Demonstration Project
- Pervious concrete specified to be installed by Certified Pervious Installer
- Mow Edge for raingarden to avoid mowing “accidents”
- Service staff education, snow plowing concerns
Single Family Residential Commercial Street
Buffalo Sewer Authority Green Infrastructure
Demonstration Project
Multi Family Residential
Aggregate Base Course Permeable Asphalt Street
Buffalo Sewer Authority Green Infrastructure
Demonstration Project
Permeable Asphalt Streets
Benefits: Buffalo Sewer Authority Green Infrastructure
Demonstration Project
- Testing Roadside Bioswales in different neighborhood settings: single family, multi family, commercial
- Demonstrate permeable asphalt street pavement
- Flow Monitoring underway
- Testing details, plantings, maintenance requirements
Challenges: Buffalo Sewer Authority Green Infrastructure
Demonstration Project
- Construction Administration, Inspection is critical
- Multi Family bioswales are narrow, high traffic, abused
- Commercial setting is much more difficult than residential
- Commercial street with retrofitting fencing, taller, more formal planting
Green Infrastructure Lessons Learned
• Site Identification is difficult, All Sites are not equal
• Targeting Distressed Property Clusters
• Identified Neighborhood Transformative Sites
• CSO reduction and Runoff reduction are two
different items
• Construction Administration is critical, many basic
mistakes made in demonstration projects
Questions