Requirements, recommendations and information for using green roofs as a BMP in the MIDS calculator
This site is currently undergoing revision. For more information, open this link.
The information on green roofs will be updated in early summer of 2013
The information on green roofs will be updated in early summer of 2013
Below is a summary of requirements, recommendations and other information for using the Minimal Impacts Design Standards (MIDS) calculator for green roofs. Links to MIDS pages and the MIDS calculator are included at the bottom of this page.
Contents
Model defaults
- Media holding capacity = 0.33 cubic feet per cubic feet
- Annual volume retained = 45%
- Phosphorus reduction (particulate and dissolved) = 0%
- TSS reduction = 85%
- TSS Event Mean Concentration = 15 mg/L
The above default values tend to be conservative values. For more information see the water quantity and water quality sections in the green roofs overview or the article on calculating credits for green roofs.
Model input requirements and recommendations
Caution: The following are requirements or recommendations for inputs into the MIDS calculator
- Media depth must be 4 inches or less
- The top surface area of the green roof cannot exceed the total impervious area for the site
Information
Information: The following information may be useful in determining inputs for the MIDS calculator
- Information on green roof design
- Guidance on characteristics of different types of green roofs
- Information on green roof construction