Michael van Niekerk, Clive Greenstone and Mike Hickman Dr. Debra Roberts, Meggan Spires and Nicci Diederichs Mander eThekwini Municipality, June 2011 Clive Greenstone and Mike Hickman, unless otherwise credited This guideline has been prepared as part of the Green Roof Pilot Project (GRPP), an initiative of eThekwini Municipality’s Environmental Planning and Climate Protection Department. The GRPP was initiated in 2008 as part of the adaptation work stream of the eThekwini Municipal Climate Protection Programme (MCPP). The aim of the GRPP is to assess the effectiveness of green roof habitats in Durban in reducing temperatures and stormwater runoff, both of which are projected to increase as a result of climate change. The co-benefits of the GRPP in terms of its role in promoting urban biodiversity are also being assessed. This guideline forms part of the Green Guideline Series, an initiative of the Greening Durban 2010 Programme. The aim of the Greening Durban 2010 Programme was to ensure that the 2010 FIFA World CupTM was hosted in an environmentally sustainable way, and that a positive environmental legacy was achieved from hosting the event in Durban. As part of that legacy, the series is now being extended in the post-World CupTM phase with this new green roof habitat guideline. The content of this guideline is intended for information purposes only and does not constitute legal advice. While every effort has been made to ensure the comprehensive nature of the information, the suggestions and tech- nologies contained herein should not be considered exhaustive. Any liability that arises from the use of the guideline is excluded. Ecoman Abbreviations and Quick Definitions Guide .............................................................................................. 2 1. Introduction ................................................................................................................................................. 3 2. Green Roof Pilot Project ......................................................................................................................... 5 2.1 Background and Introduction .......................................................................................................... 5 2.2 Location and Design .......................................................................................................................... 6 2.3 Results .................................................................................................................................................. 6 2.3.1 Structural Considerations ..................................................................................................... 6 2.3.2 Growing Media ........................................................................................................................ 7 2.3.3 Plants .......................................................................................................................................... 8 2.3.4 Increasing Biodiversity ........................................................................................................... 8 2.3.5 Reducing Stormwater Run-off ............................................................................................. 8 2.3.6 Reduce ‘Urban Heat Island Effect’ ..................................................................................... 9 2.3.7 Food Security ........................................................................................................................... 9 3. Why Create Green Roof Habitats? ...................................................................................................... 10 3.1 Creating Habitats for Biodiversity ................................................................................................ 10 3.2 Reducing Stormwater Run-off ....................................................................................................... 12 3.3 Reducing Temperature Inside Buildings ...................................................................................... 14 3.4 Reducing the ‘Urban Heat Island Effect’ ...................................................................................... 15 3.5 Extending the Life of Roofs ............................................................................................................ 17 3.6 Reducing Air Pollution ..................................................................................................................... 18 3.7 Improve Working and Living Environment ................................................................................ 19 3.8 Reducing Noise Pollution ............................................................................................................... 20 3.9 Providing Food Security .................................................................................................................. 20 4. How to Create a Green Roof Habitat ................................................................................................ 22 4.1 Getting Started .................................................................................................................................. 22 4.1.1 Structural Considerations ................................................................................................... 22 4.1.2 Safety Considerations ........................................................................................................... 22 4.1.3 Roof Slope ............................................................................................................................... 22 4.1.4 Location ................................................................................................................................... 23 4.2 Types of Green Roof Systems ....................................................................................................... 24 4.2.1 Direct Green Roof System ................................................................................................. 25 4.2.2 Modular Green Roof System ............................................................................................. 27 4.3 Choosing a Planting Medium ......................................................................................................... 29 4.4 Choosing Your Plants ...................................................................................................................... 30 4.4.1 Plant Selection ........................................................................................................................ 30 4.4.2 Plant Themes, Combinations and Communities ............................................................ 36 4.5 Edging .................................................................................................................................................. 38 5. Maintenance ................................................................................................................................................ 39 5.1 Irrigation ............................................................................................................................................. 39 5.2 Composting and Garden Waste Management ........................................................................... 41 5.3 Controlling Weeds ........................................................................................................................... 42 5.4 Controlling Pests and Diseases ..................................................................................................... 43 6. Summary and Conclusion ........................................................................................................................ 44 7. Existing Green Roof Habitats in Durban ............................................................................................. 45 8. Useful Resources ....................................................................................................................................... 46 8.1 Publications and Articles ................................................................................................................. 46 8.2 Websites ............................................................................................................................................. 46 8.3 Relevant Legislation .......................................................................................................................... 47 8.4 Green Roof Materials Suppliers .................................................................................................... 48 8.5 Green Roof Plant Suppliers ............................................................................................................ 48 8.6 Green Roof Specialists Involved in the GRPP............................................................................. 48 BTU British Thermal Unit KwH Kilowatt-hour CBD Convention on Biological Diversity LECA Light Expanded Clay Aggregate CH4 Methane MCPP Municipal Climate Protection Programme CO2 Carbon Dioxide NOx Nitrous Oxides CO Carbon Monoxide O2 Oxygen DIY Do-It-Yourself PM Particulate Matter GHG Green House Gases GRPP Green Roof Pilot Project SOx Sulphur Oxides dB Decibel TEEB The Economics of Ecosystems and EPCPD Environmental Planning and Biodiversity Climate Protection Department UNFCCC United Nations Framework Convention EMA EThekwini Municipal Area on Climate Change EPA U.S. Environmental Protection Agency VOC Volatile Organic