Modeling Tools that Support the Green Streets, Green Jobs, Green Towns Approach

There are a variety of free modeling tools available to help guide you towards using the Green Streets, Green Jobs, Green Towns (G3) approach to incorporate green streets and innovative stormwater management techniques in your community. Modeling tools support planning and design decisions on a range of scales from setting a green infrastructure target for an entire watershed to designing a green infrastructure practice for a particular site or location, such as a green street. Outputs that are particularly helpful include:

• runoff volume,
• runoff rate,
• pollutant loading, and
• cost.

Some models can predict the water quality and water quantity impacts of green infrastructure approaches. Start with simpler, less resource-intensive models and advance into more complex models that require more time and expertise.

Tools

1. EPA's Water Quality Scorecard - This EPA product is a tool that communities can use to collaboratively identify the barriers to green infrastructure in local codes and ordinances. The scorecard guides municipal staff through 230 policies, codes, and incentives that could be adapted to promote sustainable stormwater management. The scorecard also provides extensive references and case studies.
2. EPA's National Stormwater Calculator - A stormwater management model (SWMM) based desktop application that estimates the impact of land cover change and green infrastructure controls on stormwater runoff from a selected site. Estimates of runoff volume and frequency are based on local soil, topographic and climate data, and user-provided land cover and BMP data.
3. EPA's Stormwater Management Model (SWMM) with LID Controls - SWMM is used throughout the world for planning, analysis and design related to stormwater runoff, combined and sanitary sewers, and other drainage systems in urban areas. There are many applications for drainage systems in non-urban areas as well.  SWMM 5 has recently been extended to model the hydrologic performance of specific types of low impact development (LID) controls.  The LID controls that the user can choose include the following seven green infrastructure practices: permeable pavement, rain gardens, green roofs, street planters, rain barrels, infiltration trenches, and vegetative swales.
4. Watershed Resources Registry  - An interactive mapping tool to characterize and prioritize natural resource management opportunities using a Watershed Approach.  The objective of the Registry is to map natural resource areas that are a priority for preservation and to identify sites best-suited for ecosystem preservation and restoration.     
5. i-Tree Streets  - Focuses on the ecosystem services and structure of a municipality’s street tree population. Uses a sample or complete inventory to quantify and put a dollar value on trees’ annual environmental and aesthetic benefits.
6. Low Impact Development Urban Design Tools Website  - This site provides watershed managers with a new set of tools and techniques that can be used to meet regulatory and receiving water protection program goals for urban retrofits, re-development projects, and new development sites.

To access additional models that address stormwater runoff, cost, air quality, and energy consumption visit EPA's Green Infrastucture Modeling Tools webpage.