m
 
(50 intermediate revisions by the same user not shown)
Line 1: Line 1:
{{alert|The information on green roofs will be updated in early summer of 2013|alert-under-construction}}
+
[[File:mids logo.jpg|300px|right|alt=image of Minimal Impact Design Standards logo]]
 +
[[File:Target Center Arena Green Roof 1, Minneapolis, MN.jpg|300px|thumb|alt=image of target center green roof, Minneapolis, MN|<font size=3>View of the Target Center Arena green roof, located in downtown Minneapolis, Minnesota. Image by Bergerson Photography, Courtesy of The Kestrel Design Group, Inc., INSPEC, and Leo A Daly.</font size>]]
 +
 
 +
{{alert|The [http://www.mngreenroofs.org/ Minnesota Green Roofs Council] has a new [http://www.mngreenroofs.org/case-studies/database-of-minnesota-green-roofs/ database] of green roofs in Minnesota|alert-info}}
 +
 
 +
{{alert|Green roofs consist of a series of layers that create an environment suitable for plant growth without damaging the underlying roof system. Green roofs create green space for public benefit, energy efficiency, and stormwater retention/ detention.|alert-success}}
 +
 
 +
{{alert|Green roofs can be particularly effective stormwater Best Management Practices in [[Glossary#u|ultra-urban]] settings.|alert-info}}
 +
 
 +
Green roofs typically occur at the beginning of stormwater treatment trains. Green roofs provide filtering of suspended solids and pollutants associated with those solids, although total suspended solid (TSS) concentrations from traditional roofs are generally low. Green roofs provide both volume and rate control, thus decreasing the stormwater volume being delivered to downstream Best Management Practices (BMPs).
 +
 
 +
*For a literature review of green roof benefits, see [[File:green roof benefits.docx]].
 +
*The full contents of the green roofs section are contained within a pdf document. To access the pdf, link to: [[file:Green roofs.pdf]]
 +
*'''The individual articles comprising this section on green roofs may be viewed as a [[Green roofs combined|single article]].''' Note: Due to an unresolved bug, when viewing a formula in a combined article, the math markup (used for equations) is displayed.
 +
 
 +
A listing of contributors and participants to the development of pages comprising the green roof section of this Manual appears in the Acknowledgements section.
 +
 
 +
<font size=4>[[Acknowledgements for green roofs|Acknowledgements]]</font size>
  
 
*[[Overview for green roofs]]
 
*[[Overview for green roofs]]
Line 5: Line 22:
 
*[[Design criteria for green roofs]]
 
*[[Design criteria for green roofs]]
 
*[[Construction specifications for green roofs]]
 
*[[Construction specifications for green roofs]]
*[[Construction observations for green roofs]]
+
<!--*[[Construction observations for green roofs]]-->
 
*[[Assessing the performance of green roofs]]
 
*[[Assessing the performance of green roofs]]
*[[Operation and maintenance of green roofs]]
+
*[[Operation and maintenance (O&M) of green roofs]]
 +
*[[Operation and maintenance of green roofs - supplemental information]]
 +
**[[Operation and maintenance of green roofs]] - we recommend using the above two pages
 
*[[Calculating credits for green roofs]]
 
*[[Calculating credits for green roofs]]
 
*[[Cost-benefit considerations for green roofs]]
 
*[[Cost-benefit considerations for green roofs]]
 
*[[Plant lists for green roofs]]
 
*[[Plant lists for green roofs]]
*[[Additional considerations for green roofs]]
+
<!--*[[Additional considerations for green roofs]]-->
 +
*[[Case studies for green roofs]]
 
*[[Links for green roofs]]
 
*[[Links for green roofs]]
 
*[[References for green roofs]]
 
*[[References for green roofs]]
 
*[[Supporting material for green roofs]]
 
*[[Supporting material for green roofs]]
 
*[[Green roofs terminology and glossary]]
 
*[[Green roofs terminology and glossary]]
 +
*[[Green roof fact sheet]]
 +
*[[Requirements, recommendations and information for using green roofs as a BMP in the MIDS calculator]]
 +
 
<br>
 
<br>
  
<!--*[[Acknowledgements for green roofs]]
+
<!--Several [[Fact sheets for green roofs|fact sheets]] for green roofs provide overview information and information on design, construction and maintenance, and volume and pollutant removal.-->
 
 
Several [[Fact sheets for green roofs|fact sheets]] for green roofs provide overview information and information on design, construction and maintenance, and volume and pollutant removal.-->
 
 
 
Green roofs consist of a series of layers that create an environment suitable for plant growth without damaging the underlying roof system. Green roofs create green space for public benefit, energy efficiency, and stormwater retention/ detention.
 
 
 
==Design criteria==
 
[[file:Green roofs 2.jpg|thumb|300px|alt=Photo of Green roof|<font size=3>Photo of a green roof.</font size>]]
 
Structural load capacity, how much weight the roof can hold, is a major factor in determining whether the green roof is “[[Glossary#E|extensive]]” or “[[Glossary#I|intensive]]”. Vegetation selection is based on numerous factors including, growth medium depth, microclimate, irrigation availability and maintenance. A leak detection system is recommended to quickly detect and locate leaks.
 
 
 
==Benefits==
 
*Reduce, delay, and cool stormwater runoff
 
*Can significantly lower building energy costs
 
*Provide habitat for birds and insects
 
*Increase longevity of traditional roofing systems by protecting from ultraviolet rays
 
*Reduce carbon dioxide levels and heat island effect
 
*Local food production
 
*Decreased stormwater utility fee
 
*Aesthetics
 
*Create gardens even where open space is not available at grade
 
*Can be used for stormwater treatment in many areas where other LID techniques might not work (e.g. redevelopment projects with limited open space, areas with high bedrock, karst topography, contamination)
 
*Beneficial in hospitals (see Ulrich, 2002)
 
 
 
==Limitations==
 
*Initial capital cost is higher (Note: considering lifecycle costs may make green roof a more attractive investment due to increased roof lifespan, increased energy efficiency, and stormwater benefits).
 
*Leaks can cause significant damage and can be hard to locate and repair without an electronic leak detection system. ANSI/SPRI RP-14 Wind Design Standard for Vegetated Roofing Systems, available at http://www.spri.org, gives guidelines on how to design to minimize wind damage in green roofs, including, for example, how to evaluate what roofs are too windy for a green roof, and where a green roof may need extra wind protection.
 
*Conditions can be harsh for vegetation establishment.
 
*Maintenance needs can be higher than traditional roofing system.
 
*Building codes and insurance
 
 
 
==Management suitability==
 
*Water Quality (V<sub>wq</sub>) - High
 
*Channel Protection (V<sub>cp</sub>) - Med.
 
*Overbank Flood Protection (Vp<sub>10</sub>) - Low
 
*Extreme Flood Protection (Vp<sub>100</sub>) - Low
 
*Recharge Volume (V<sub>re</sub>) - Low
 
 
 
See [[Unified sizing criteria]] for explanation of these terms.
 
===Mechanisms===
 
*Screening/ Filtration
 
*Temperature Control
 
*Evaporation
 
*Transpiration (if vegetated)
 
*Soil Adsorption
 
*Biological/ Micro. Uptake
 
 
 
==Pollution removal==
 
*Total Suspended Solids - 90%
 
*Nutrients - Total Phosphorus/Total Nitrogen - 100%/ 20%
 
*Metals - Cadmium, Copper, Lead, and Zinc - 80%
 
*Pathogens - Coliform, Streptococci, E. Coli - 65%
 
NA Toxins - Hydrocarbons, Pesticides
 
 
 
==Site factors==
 
*Drainage Area - Rooftop
 
*Max. Slope - NA.
 
*Min. Depth to Bedrock - NA.
 
*Min. Depth to Water Table - NA.
 
*SCS Soil Type (can be used in C&D soil types with modifications (e.g. underdrains)) - NA
 
*Freeze/ Thaw Suitability - Good
 
*Potential Hotspot Runoff (requires impermeable liner) - Suitable
 
 
 
Note: Pollution removal percentages apply to volume of runoff treated, and not to volume by-passed
 
 
 
==Description==
 
[[file:green roof schematic.jpg|thumb|500px|alt=Schematic of green roof|Schematic of green roof]]
 
 
 
There are two systems of green roofs, extensive and intensive, composed of the same system of layers. Extensive systems are lighter, typically have 6 inches or less of growing medium, use drought tolerant vegetation, and can structurally support limited uses (such as maintenance personnel). Intensive systems are heavier, have a greater soil depth, can support a wider range of plants, and can support increased pedestrian traffic.
 
<p>Rainfall is initially intercepted by vegetation, held on foliage, or soaked up by plant roots. Any remaining runoff filters through the growing medium and is drained away from the roof’s surface by the drainage layer. This water can be captured in cisterns to irrigate plants or for other re-use purposes. Some drainage systems use small depressions to store excess water for uptake during drier conditions ([http://www.rwmwd.org/index.asp?Type=B_BASIC&SEC=%7B399EA196-60B5-4C83-A433-8B97901418D1%7D RCWD]), while others provide an overflow for larger rainfall events.</p>
 
  
 +
<noinclude>
 
[[Category:BMP]]
 
[[Category:BMP]]
 +
</noinclude>

Latest revision as of 20:30, 3 August 2022

image of Minimal Impact Design Standards logo
image of target center green roof, Minneapolis, MN
View of the Target Center Arena green roof, located in downtown Minneapolis, Minnesota. Image by Bergerson Photography, Courtesy of The Kestrel Design Group, Inc., INSPEC, and Leo A Daly.
Information: The Minnesota Green Roofs Council has a new database of green roofs in Minnesota
Green Infrastructure: Green roofs consist of a series of layers that create an environment suitable for plant growth without damaging the underlying roof system. Green roofs create green space for public benefit, energy efficiency, and stormwater retention/ detention.
Information: Green roofs can be particularly effective stormwater Best Management Practices in ultra-urban settings.

Green roofs typically occur at the beginning of stormwater treatment trains. Green roofs provide filtering of suspended solids and pollutants associated with those solids, although total suspended solid (TSS) concentrations from traditional roofs are generally low. Green roofs provide both volume and rate control, thus decreasing the stormwater volume being delivered to downstream Best Management Practices (BMPs).

  • For a literature review of green roof benefits, see File:Green roof benefits.docx.
  • The full contents of the green roofs section are contained within a pdf document. To access the pdf, link to: File:Green roofs.pdf
  • The individual articles comprising this section on green roofs may be viewed as a single article. Note: Due to an unresolved bug, when viewing a formula in a combined article, the math markup (used for equations) is displayed.

A listing of contributors and participants to the development of pages comprising the green roof section of this Manual appears in the Acknowledgements section.

Acknowledgements


This page was last edited on 3 August 2022, at 20:30.