Science Inventory

Green Roofs for Stormwater Runoff Control

Citation:

Berghage, R., D. Beattie, A. Jarrett, C. Thurig, F. Razaei, AND T. OCONNOR. Green Roofs for Stormwater Runoff Control. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-09/026, 2009.

Impact/Purpose:

To share information

Description:

This project evaluated green roofs as a stormwater management tool. Specifically, runoff quantity and quality from green and flat asphalt roofs were compared. Evapotranspiration from planted green roofs and evaporation from unplanted media roofs were also compared. The influence of media type, media depth and drought during plant establishment on plant growth and long-term management of media pH were investigated. The goal of the project was to provide high-quality replicated data which could be used to develop and refine reliable anticipated runoff volumes and loadings from green roofs, respectively, as well as evaluate factors which impact plant growth and stablishment. Results indicate that the green roofs are capable of removing 50% of the annual rainfall volume from a roof through retention and evapotranspiration. Rainfall not retained by green roofs is detained, effectively increasing the time to peak, and slowing peak flows for a watershed. There are seasonal considerations as more runoff is generated during winter and for many summer storms there was no runoff. Green roof runoff does contain concentrations of some nutrients and other parameters, but values are in line with other planted systems. Due to the volume reduction, actual nutrient loadings from green roofs are less than asphalt roofing runoff or otherwise manageable at the downspout.

URLs/Downloads:

Green Roofs for Stormwater Runoff Control

Record Details:

Record Type: DOCUMENT (PUBLISHED REPORT/REPORT)
Product Published Date: 03/26/2009
Record Last Revised: 08/13/2012
OMB Category: Other
Record ID: 205444

Organization:

U.S. ENVIRONMENTAL PROTECTION AGENCY

OFFICE OF RESEARCH AND DEVELOPMENT

NATIONAL RISK MANAGEMENT RESEARCH LABORATORY

WATER SUPPLY AND WATER RESOURCES DIVISION

URBAN WATERSHED MANAGEMENT BRANCH