Looking Ahead: NYC Green Infrastructure Program
Hudson River Foundation September 19, 2016
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NYC Water Quality Improvement Program
Data from Harbor Survey Program.
1985
Fecal Coliform Bacteria: < 100 cfu/100 mL 100 – 200 201 – 2,000 >2,000
2015
$10B investment since the early 2000s has yielded the highest water quality observed in the NYC Harbor in recent history
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NYC Green Infrastructure Program
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Current GI Construction Timeline
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GI Program Stats • Over 3,800 GI assets built, mostly bioswales, managing over 400 impervious
acres • Spent over $250 million towards the program in capital funding
• Over $900 million in capital budgeted through Fiscal Year 2025
Impervious Area CSO Reduction
Total Impervious Area (Ac)
Managed Area (Ac)
% Imp. Area Managed
Volume Reduction (MG/yr)
% Reduction
78,749 1,182 1.5% 507 2.4%
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Infiltration Considerations - Bedrock
Depth to Bedrock
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Infiltration Considerations - Groundwater
Depth to Groundwater
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ROW Siting Criteria ROW Siting Criteria challenges:
Mature Trees
Sidewalk widths (8’ or 5’)
Fire Hydrants
Pedestrian Ramps
Building Entrances/Exits
Driveways
Muni Meters/ parking meters
Bus Stops
Unfavorable subsurface conditions
Utility conflicts
Additional Additional
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NYC Land Use Distribution
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Looking Ahead: Program Shifts 1. Moving out of the streets and scaling up public and private properties
2. Developing new tools to overcome siting and design challenges
3. Considering long-term operations and maintenance costs
4. Diving into costs fluctuations and variability
5. Determining what is “cost-effective”
6. Aligning CSO and MS4 Program
Before After
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Looking Ahead: The Green/Grey Balance • ~30 Billion Gallons of CSO/Year
• NYC is required to complete 11 waterbody LTCPs, and one city-
wide LTCP
• Current obligated to spend an additional $3.3 Billion in grey
investments over already planned work
• Including large grey CSO storage planned in three waterbodies as
part of LTCP
• Currently, the NYC Consent Order has the CSO reductions in the
baseline, which doesn’t allow us to make decisions on a watershed
basis.
• GI costs per impervious acre managed can range from $400,000-
$900,000 depending on the various constraints we’ve
encountered.
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