The Nation’s First Green Infrastructure Portfolio Standards

A Green Infrastructure Portfolio Standard would help cities scale up their green infrastructure, especially in highly urbanized areas in need of stormwater management methods.

A Green Infrastructure Portfolio Standard would help cities scale up their green infrastructure, especially in urbanized areas in need of stormwater management methods.

For the past year, CNT, in partnership with American Rivers and the Great Lakes and St. Lawrence Cities Initiative, has been working with officials in Milwaukee, Wisconsin and Grand Rapids, Michigan to develop a new way to manage stormwater in developed urban settings: the Green Infrastructure Portfolio Standard (GIPS). The GIPS pilot program takes a cue from the popular Renewable Portfolio Standard and Energy Efficiency Portfolio Standard policies enacted in many states across the country to encourage renewable energy and energy efficiency use, respectively. The GIPS is intended specifically to help developed areas scale up green infrastructure practices relatively quickly, since stormwater regulations that apply only to new developments or redeveloped sites are inadequate for this purpose.

For too long, stormwater runoff has been treated as a nuisance and a waste to be disposed of, rather than a vital asset to be managed carefully. Cities that thrive in the future will make better use of such important resources, in turn providing more benefits to their residents and businesses and reducing the cost of living and doing business. CNT’s Water Program identifies, develops, and implements creative solutions that make effective use of our water resources. The GIPS program is a perfect example.

Below is a quick update on how the GIPS pilot projects in Milwaukee and Grand Rapids are progressing. Download our GIPS fact sheet for more information.

Grand Rapids
The Grand Rapids GIPS pilot area contains roughly 200 acres of residential, commercial, and industrial properties. Within this area, the City is carrying out several projects to eliminate combined sewer overflows and a state-funded street resurfacing project. These are opportunities for the GIPS team to integrate green infrastructure practices into planned work. The area is primarily in one sewer shed, or drainage area with a single outfall, which makes it easier to measure runoff and track progress in the reduction of both stormwater runoff volume and water pollution.

The Grand Rapids Department of Environmental Services has identified several dozen green infrastructure projects within the project area to implement in the first year, which include street rain gardens with infiltration basins, porous pavement projects on public and private property, and a rain barrel program for residents. The Task Force is in the process of setting annual goals for runoff retention for the next 10 years. An annual goal, for example, could be that the installed green infrastructure retain an additional 1 percent of the runoff from the area that occurs from a one-inch rainfall. That would mean retaining roughly 15,000 more gallons of runoff each year for every 1-inch rainstorm. The Department has also begun developing a written policy committing to this goal and to implementing the GIPS program as a standard procedure.

If Grand Rapids continues the GIPS program as currently planned, it will install enough green infrastructure to reduce the runoff from the project area by at least 20 percent in the next two decades, which will greatly assist in the elimination of the flooding and combined sewer overflows in the area that today result from typical storm events.

Milwaukee
The City of Milwaukee has selected two GIPS project areas located in sewer sheds that drain into nearby waterways with significant flooding issues. These areas already have several completed green infrastructure projects, such as street-side rain gardens or bioswales. The project areas also have potential for future public projects that will incorporate green infrastructure features. Using the City’s Geographic Information Systems (GIS) database, CNT matched the City’s proposed working areas to specific sewer sheds, ensuring that the runoff from the sites can easily be monitored and measured. Next steps for the Milwaukee GIPS include estimating the current runoff volume to create a baseline, identifying green infrastructure projects for the first year of the program, and calculating how much rain those projects will be able to retain. Finally, the City will need to set annual goals for how much rain to keep on-site with future GI installations.

Download the GIPS fact sheet ››