Ida Programs

Green Infrastructure Expansion

Program Partners

• NYC Department of Design and Construction (DDC)
• NYC Department of Environmental Protection (DEP)
• New York City Housing Authority (NYCHA)

Program Descriptions

NYCHA Green Infrastructure

Green Infrastructure (GI) describes an array of practices that use or mimic natural systems to manage stormwater runoff. GI systems collect stormwater from streets, sidewalks, and other hard surfaces before it can enter the sewer system or cause local flooding. By reducing the amount of stormwater that flows into the sewers, GI helps prevent sewer overflows and backups and improves the health of local waterways.

In New York City, green infrastructure takes many shapes and forms including but not limited to:

• Rain gardens are planted areas in the sidewalk that are designed to collect and manage stormwater. Rain gardens are vegetated or landscaped depressions designed to promote infiltration of stormwater runoff into the underlying soil.
• Stormwater green streets, like rain gardens, are planted areas designed to collect and manage stormwater. However, green streets are typically constructed in the roadway, are usually larger than rain gardens, and have varying lengths, widths, and soil depths based on the characteristics of the existing roadway.
• Infiltration basins are designed to store rainwater beneath a surface that closely mimics its surroundings, like grass or concrete. They are similar in functionality to rain gardens in that they capture stormwater, yet they maintain the look and feel of the existing sidewalk. Basins hold the water so that it can be collected and released into the surrounding ground at a slower rate.
• Green roofs are made of a top vegetative layer that grows in an engineered soil, which sits on a drainage layer. A green roof can be intensive, with thicker soils that support a wide variety of plants, or extensive, covered in only a light layer of soil and minimal vegetation.
• Blue roofs are designed without vegetation solely to detain stormwater. Weirs at the roof drain inlets create temporary ponding and gradually release stormwater.
• Subsurface detention systems with infiltration capability provide temporary storage of stormwater runoff underground. These systems have an open-bottom and can incorporate perforated pipe and stormwater chambers for added detention volume. Systems are primarily designed with a gravel bed that stores water until it can infiltrate into the ground.
• Permeable paving is a range of materials and techniques, such as permeable pavers or porous concrete, which allow water to seep in between the paving materials and be absorbed into the ground. Permeable paving can be used instead of traditional impermeable concrete or asphalt.
• “Cloudburst projects” employ a combination of GI and grey infrastructure to absorb, store, and transfer stormwater to minimize flooding from cloudburst events, which are sudden, heavy downpours in a short amount of time. Cloudburst projects may also feature special community amenities and open spaces for use by the public.

Through this program, the City proposes to use CDBG-DR funds to expand the City’s GI network in areas impacted by PTC Ida. Softening the landscape and providing more stormwater storage will provide a first line of defense during large precipitation events and will allow the City’s grey infrastructure (e.g., sewers and water treatment facilities) to operate more efficiently. Allocating CDBG-DR funds to this activity will allow the City to expand its GI network more quickly than anticipated, and to ensure that GI projects that will benefit low- and moderate-income areas or households will be prioritized.