Green Infrastructure Reference Resources

This is a collection of resources pertaining to Green Infrastructure. The resources listed here are referenced in the CDRPC GI Code Audit.


Roof top disconnect


Combined Sewer Overflow (CSO)

Dry Swales

Dry wells



example: Cluster development

example: Open space design

example: Conservation subdivision

Conservation subdivision review process

Irregular lot shapes

Temporary Ponding

Transfer of development rights

Rooftop runoff



Natural resource protection

example: Natural Resource Buffers

Density and natural resource areas

Density bonus

Consolidated open spaces

Forest and tree protection

Funding arrangements for open space

Maintenance of open space in natural condition

Natural vegetative cover requirements

Soil conservation

Timber Harvesting

Tree replacement






Areas landscaped for catching and filtering stormwater before entering the ground. Bio-retention can be of any scale and consists of a grass buffer strip, sand bed, ponding area, organic layer or mulch layer, planting soil, and plants.

Example: bio-retention & stormwater practices







a tank for storing collected stormwater, creates a reservoir for non-potable uses such as flushing a toilet or irrigation.

For more information, click here.

Combined Sewer Overflow (CSO)

A combined sewer system (CSS) collects rainwater runoff, domestic sewage, and industrial wastewater into one pipe. Under normal conditions, it transports all of the wastewater it collects to a sewage treatment plant for treatment, then discharges to a water body. However, when rainwater is falling and collecting at a faster rate than the system can handle, it creates an overflow.

Stormwater Model Codes

Municipal codes are used to regulate land-use and behavior. They can be applied to everything from road design to GI infrastructure.

Example: Cul-de-Sac Regulation
Example: Pedestrian walkways between cul-de-sacs
Example: Sidewalks must slope towards the front yard
Example: Driveway width
Example: Using pervious materials for driveways and “two track” design
Example: Shared Driveways
Example: Driveways slope towards yard and not street
Example: Parking lot design
Example: Parking lot requirements (Part G)
Example: Pervious materials for parking lots (part A)
Example: Parking lot landscaping
Example: Parking requirements
Example: Shared Parking
Example: Shared Parking Agreements
Example: Parking ratios & proximity to mass transit
Example: Floodplain management
Example: Local erosion and sediment control law
Example: Erosion requirements
Example: Delineation of natural conservation areas (part F)
Example: Native vegetation protection (part G)
Example: Stream buffers & Wetland Buffer

Complete Streets

Streets that have accommodation for everyone. They serve pedestrians, motorists, cyclists, and public transit riders. Complete streets offer safe crossings and easy access to shops, and also has green space intermixed.

Example: Road Width
Example: Grid Plan
Example: Complete Streets Legislation
Example: Sidewalk Guidelines
Example: Parking best practices




FEMA Flood Insurance Program

A program that enables property owners in participating communities to purchase insurance protection, administered by the government, against losses from flooding, and requires flood insurance for all loans or lines of credit that are secured by existing buildings, manufactured homes, or buildings under construction, that are located in a community that participates in the NFIP. The program is offered by the Federal Emergency Management Agency (FEMA).

Intermittent Streams

Streams that are only present hours or days after rainfall and wet seasons. These streams cease to flow for weeks and months at a time when weather is warm and dry.


A type of alternative turnaround structure that can be used in low density residential areas.

Multi-Use Trail

A path physically separated from motor vehicle traffic by an open space or barrier and either within a public right of way or easement, which accommodates two-way non-motorized travelers including pedestrians, bicyclists, joggers, and skaters.

Example: Connective Pedestrian Path
Example: Multi-use trail plan





Natural Resource Inventory (NRI)

An NRI compiles and describes important naturally occurring resources such as forests, wetlands, surface and ground waters, and farmland within a given locality (e.g., municipality, watershed, or region).

Parking Ratios

The number of parking spaces available on a per-unit, or sometimes square footage, basis.

Passive Recreation

Non-consumption uses of space, such as wildlife observation, biking, walking, and canoeing. The objective of passive recreation is to limit the disturbance on ecosystems while enjoying the outdoors.

Pervious Materials

Pervious materials permit water to enter the ground by virtue of their porous nature, or by large space in the material. This helps reduce stormwater runoff as more water is naturally absorbed into the ground.

Right of Way Width

The width of road and sidewalks, as well as the green space in between the two, that is reserved for public use. Beyond the right of way is typically private property.

Shared Parking

An example of shared parking is when adjacent property owners share their parking lots and reduce the number of parking spaces that each requires. Large parking lots dedicated to a single property are rarely ever full, so shared parking among multiple properties can make more efficient use of the space.

Transfer of Development Rights (TDR)

An incentive based program that allows landowners to sell development rights from their land to a developer or other interested party who then can use these rights to increase the density of development at another designated location.

Center for Land Use Education: Planning Implementation Tools Transfer of Development Rights (TDR)

Queuing Street

Some local roads (usually longer, more continuous roads) have 2 travel lanes, whereas others are “queuing streets”. A queuing street has only 1 travel lane (when on-street parking is well-used) and drivers must pull over to allow oncoming traffic to pass. Queuing streets have 2 main benefits:

  • Containing built-in traffic calming to lower the speed of traffic, and
  • Minimizing the pavement width, which reduces the demand on the drainage system and minimizes the environmental impact.


Example 2: Queuing Street


Resources from The Center for Watershed Protection

Introduction to Better Site Design and the Code and Ordinance Worksheet: Runoff Reduction Practices

Types of Curb Extensions


Best Green Infrastructure Practices