The Benefits and Challenges Associated with Green ...€¦ · The Benefits and Challenges...

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