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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Scaling Up Green Infrastructure

www.nyc.gov/dep/gimap

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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.