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Water Environment Transportation Energy Facilities
TheBigGreenApple
November 16, 2015
Maine Stormwater Conference+ NE IECA Annual ConferenceSouth Portland, Maine
Virginia Roach, P.E.
Overview
• Green infrastructure approach in New York City
• Programmatic areas of the NYC Green Infrastructure Program
• Right‐of‐Way Program• Public Retrofit Program
• Maintenance• Costs
NewYorkCityGreenInfrastructureApplicationRatesandMilestoneSchedule
0%
1%
2%
3%
4%
5%
6%
7%
8%
9%
10%
2010 2015 2020 2025 2030
Initial 1.5% Additional 2.5% Additional 3.0% Final 3% 10% Target
$1.5 billion projected over the 20‐year program.
Manage 1” of stormwaterrunoff from 10% of impervious surfaces in combined sewer areas by 2030
AdaptiveManagementPlan2014AnnualReportSuccesses
• 3 demonstration areas (70 ROWBs)
• Manage 14% of impervious areas
• 20% reduction in runoff to combined sewer in typical storm
• Early 2015• 300 ROWBs constructed• 1,300 under construction
• End of 2015• 5,600 practices projected
• Constructed, in construction, registered with Notice to Proceed
Area‐WideDesignBB‐008
The Bronx
Queens
Brooklyn
= does not meet water quality standards(pathogens/DO)
SiteSelectionProcess1.TributaryDrainageAreaAnalysis
• BB‐008 (1,200 acres): More than 4,700 ROWBs needed to manage 100% of impervious ROW area
SiteSelectionProcess2.Walk‐ThroughstoInvestigatePotentialSites
• BB‐008: More than 950 Preliminary ROWB locations identified
DOTBioswaleSitingCriteria
ROW Siting Criteria examples:• Mature Trees• Sidewalk widths (8’ or 5’)
• Fire Hydrants• Pedestrian Ramps• Building Entrances/Exits• Driveways• Muni Meters• Bus Stops
SiteSelectionProcess3.BoringsandPermeabilityTests
• BB‐008• 646 geotechnical investigations representing 895 sites
• 70% success rate• Permeable soils• Low groundwater
SiteSelectionProcess4.LimitedSurvey
• BB‐008• 4 ROWB construction contracts
• 375 ROWBs• $12,300 per ROWB
Edenwald Houses
• Hutchinson River CSO tributary area (HP‐024)
• Largest NYCHA development in the Bronx
• 41 buildings• 3‐story and 14‐story• Community Center
• 5,450 residents
Edenwald Houses
Total drainage area• 53 acres• 54% impervious
• Sidewalks 17%• Buildings 14%• Roadways 8%• Parking areas 3%
Edenwald HousesGeotechnicalInvestigations:LowPermeabilityRates
• 0.00014 to 0.13 in/hr at Edenwald Houses• 0.2 in/hr min for groundwater recharge (NJ)• 0.17 in/hr min for stormwater infiltration (MA)
• At 0.13 in/hr – 3 days to infiltrate 10 inches of water• High percentage of fines in soils (>20%)
Edenwald Houses:FinalDesignofGreenInfrastructurePractices
• Vegetated bioretentionareas
• Rain gardens• Rooftop runoff redirection to green infrastructure
• Porous pavements
EdenwaldHouses35%ofImperviousAreaManaged
Not Managed by Green Infrastructure
65%
Building Entrances, Walkways and Vehicle
Access Drives (Permeable Pavers, Porous Asphalt, Pervious Concrete)
18%
Vegetated BioretentionAreas / Rain Gardens
11%
Parking Areas (Porous Asphalt)
6%
Edenwald HousesPercent of Impervious Area Managed by Green Infrastructure
ROWBMaintenance
• Current NYC DEP practices• Inspect and remove trash every two weeks during construction
• Inspect and remove trash every week after construction
• Evaluating maintenance practices under ongoing R&D Program
• GIS‐Based Project Tracking and Asset Management System
VegetatedBioretention Area/RainGardenMaintenance
• Highest maintenance first two years
• Seasonal weeding, raking and pruning
• Infiltration improves over time as roots establish
PorousPavementMaintenance
• Inspect once per year• Vacuum sweep two to four times per year
• Power wash if needed• Permeable pavers
• Regenerative air or traditional sweeper
• Replenish joint material
HartfordGreenCapitolsO&MManual
Porous Asphalt Winter Maintenance:• Remove snow promptly• Slightly raised plow
preferred• Do not use sand
EdenwaldHouses‐ NorthCostperImperviousAcreManaged
$‐
$100,000
$200,000
$300,000
$400,000
$500,000
$600,000
$700,000
Rain Gardens VegetatedBioretention Areas
Veg Bio Areas w/PlumbingRedirection
Porous Pavements Total
Engineer's Estimate
Bid Costs