This presentation highlights the initiative by the NYC DEP to prepare the city for a changing environment.

1. Looking Ahead:
NYC Green Infrastructure Program
Hudson River Foundation
September 19, 2016

2. 2
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

3. 3
NYC Green Infrastructure Program

4. 4
Current GI Construction Timeline

5. 5
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%

6. 6
Scaling Up Green Infrastructure
www.nyc.gov/dep/gimap

7. 7
Infiltration Considerations - Bedrock
Depth to Bedrock

8. 8
Infiltration Considerations - Groundwater
Depth to Groundwater

9. 9
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
AdditionalAdditional

10. 10
NYC Land Use Distribution

11. 11
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

12. 12
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.