Earlier this year, the Clear Waters Initiative Charter, part of the Wisconsin DNR’s Green Tier program, published a Technical Guidance Document for Green Roofs. Information from this document has now been incorporated into the Dane County Stormwater Manual, along with additional resources to support design implementation.
Green roofs are an engineered roofing system utilizing soil and vegetation. This form of green infrastructure is becoming more prominent in the region as a way to effectively manage stormwater in-place while providing significant social, economic, and environmental benefits, particularly in urban environments.
There are many considerations that go into the successful design and implementation of a green roof. Locally, there has been a need for additional guidance on best practices for employing green roofs as a stormwater management practice, as well as how to model these systems to meet local stormwater ordinances.
In 2022, the Clear Waters Initiative Charter set out to consolidate and improve on design guidelines and modeling parameters, as well as construction and maintenance considerations. CARPC staff served on the technical guidance committee that developed the Technical Guidance Document for Green Roofs finalized in early 2023.
More recently, the Dane County Land & Water Resources Department updated their Dane County Stormwater Manual to include a page dedicated to Green Roofs which pulls information from the guidance document and provides additional resources to assist designers with implementing some of the design considerations. The webpage contains a calculator, links to other useful resources, as well as a link to the guidance document.
CARPC became an official Signatory Member of the Clear Waters Initiative Charter in 2021. The Charter’s basic aim is to reduce the overall nutrient and sediment delivery to Dane County’s lakes and streams beyond current state and local requirements.
To see examples of green roofs in the greater Madison area, check out CARPC’s Greater Madison Region Green Infrastructure Viewer, an ArcGIS webmap showcasing a collection of representative and exemplary projects using green infrastructure practices for urban stormwater management.
