The Benefits and Challenges Associated with Green Infrastructure Practices

Transcription

1 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

2 Agenda Overview of Green Infrastructure Practices Critical GI Practices for Stormwater, Floodplain and CSO Applications Case Studies GI Benefits, Challenges, Lessons Learned Questions

3 Green Infrastructure Practices Applicable to Stormwater, Floodplain Management, and CSO Control Stormwater Wetlands Stream Restoration Green Streets, Bioinfiltration Demonstration Projects

4 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

5 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

6 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

7 Stormwater Wetlands for Quantity/Quality Control Wetland Conservation Area, New Albany, Ohio

8 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

9 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

10 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

11 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.

12 Challenges: Wetland Conservation Area, New Albany, Ohio - Cost of land - Identifying Opportunity Sites - Permitting - Hydrology uncertainty, backup wells, - Vegetation Establishment Uncertainty - Invasive species

13 Stream Restoration for Flood Relief and Habitat Enhancement Lake County, Ohio Stormwater Management Dept. Kellogg Creek Restoration

14 Floodplain Restoration in Narrow Stream Easement Stream Restoration for Flood Relief, and Habitat Enhancement Lake County, Ohio Stormwater Management Dept. Kellogg Creek Restoration

15 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

16 Benefits: Kellogg Creek Restoration, Lake County, Ohio Lineal Feet of Stream Restoration Foot Flood Elevation Reduction - Reduced peak discharges by 25% - Removed 5 structures from Floodplain - Only had 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

17 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

18 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 $91 million

19 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

20 Green Streets: Philadelphia/PennDOT I-95, Phase 2

21 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.

22 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,

23

24 Pervious Pavers Parking Lane Tree Box Application

25 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

26 Mayfield Heights City Hall Green Infrastructure Demonstration Project Residential and Commercial Green Infrastructure Demonstrations

27 Mayfield Heights City Hall Green Infrastructure Demonstration Project Forested Parking Lot Demonstration Before After

28 Mayfield Heights City Hall Green Infrastructure Demonstration Project Commercial Parking Lot Demonstration Pervious Concrete

29 Mayfield Heights City Hall Green Infrastructure Demonstration Project Residential Downspout Disconnection Demonstration Before After

30 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

31 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

32 Buffalo Sewer Authority Green Infrastructure Demonstration Project Single Family Residential Commercial Street Multi Family Residential

33 Buffalo Sewer Authority Green Infrastructure Demonstration Project Permeable Asphalt Streets Aggregate Base Course Permeable Asphalt Street

34 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

35 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

36 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

37 Questions