Graeme Hopkins Hopkins.Graeme@saugov.sa.gov.au May 2008 South Australian Government Incentive Program: Bushtops for Green Roofs and Walls South Australian Government Incentive Program: Bushtops for Green Roofs and Walls The South Australian Government, through its planning arm Planning SA, is leading the development of an innovative green roof and living wall incentive program to bring the Australian “bush” into the city of Adelaide – “Adelaide’s innovative green wall and roof incentive policy set to be a model for other Australian cities” heads up an article in the Winter 2008 issue of the North American Living Architecture Monitor. This incentive program encourages Government agencies to implement green roofs and walls, but also demonstrates the complexity and interdependency of the interaction between ecosystems. There are four components that make up this program: what are bushtop roofs and walls, creating stepping stone corridors, integration into green infrastructure, and increased residential density. First of all, we need an understanding or an explanation of what these components are and how they integrate with each other to create a sustainable environment. Bushtops Bushtops are a series of living walls and green rooftops, that mimic the endemic ecosystems of the original landscape of the city, in this particular case the City of Adelaide. Bushtops are not just the physical structure of habitats or ecosystems, they introduce the relevent animal species into this type of green roof and living wall from the early design and implementation stages. Particular emphasis is placed on providing habitat for species that were once common in the Adelaide Plains, by planting selected native grasses, sedges and flowering plants. Bird boxes will be installed into the various ecosystems, as well as bat boxes that attract micro-bats, useful in the control of mosquitoes and flying ants. Bushtop ecosystems allow natural systems to operate processes such as: stormwater retention, improving water quality, evaporative cooling from plants, bio-filtration of air- bourne pollutants, and increased carbon dioxide/oxygen exchange through photosysnthesis or carbon sinks. A good example of this process is creating a constructed wetland ecosystem as a bushtop roof or wall to treat the grey water from the building and then returning the water back to the building as recycled water or even as potable drinking water. Stepping Stone Corridors The plan is to linked individual projects together, based on patch dynamics and metapopulation theories, to form stepping stone wildlife corridors across the central business district to restore the original migration patterns of birds, insects and certain animals. Green walls will connect the bushtops to the ground and allow the passage of animals and insects between the vertical and horizontal planes. The projects will be carefully integrated with current research at the School of Urban Ecology at the University of South Australia and it is expected that Planning SA’s program will be a major platform for the reintroduction of species back into Adelaide’s urban environment. Green Infrastructure Green infrastructure is a process of designing natural systems into the urban environment, or using natural systems to replace or augment existing services that support the built infrastructure systems. The city is an urban ecosystem, with natural systems being smaller ecosystems within the overall urban ecosystem. These systems utilise the complex interactions of the earth’s natural cycles (hydrologic, nitrogen, Graeme Hopkins Hopkins.Graeme@saugov.sa.gov.au May 2008 South Australian Government Incentive Program: Bushtops for Green Roofs and Walls oxygen, carbon and others). These elements in the natural systems provide processes that repair, transform and transport matter, clean water and break down pollutants. These processes are vital for a healthy sustainable urban ecosystem. Green roofs and walls become part of a multi-layered corridor by bio-mimicking natural sytsems to create green infrastructure throughout the city. This green infrastructure adapts to the changing conditions caused by climate change. Green roofs and walls are one of many tools to be used in the urban environment affected by climate change. For instance they have an important role to play in stormwater management at the source, reducing the heat island effect, and providing carbon sinks. The green roofs and living walls mimic natural systems in many ways, but are particularly important for the removal of pollutants through capturing pollutant particles on plant leaves and deposits on the roots, where micro-organisms feed to convert this into water, carbon dioxide and nutrients. This process provides water and water vapour as an end product. The green roofs and living walls have all the same natural systems as the ground level environment, but are set up artificially. The stormwater chain in a natural system is the capture and retention of stormwater at its source, and its reuse or infiltration. In green infrastructure this natural process is mimicked by using green roofs and living walls to capture and retain the rainwater that falls on them, thus eliminating a large volume of stormwater at its source. Increased Residential Density The SA government has a policy of increasing the population, especially in the inner metro areas through infill programs. This increased density development is usually to the detriment of open space or the landscape bio-mass. The increased built form can be offset by using green roofs and walls integrated into the design of the built form. By employing living wall methodolgy, the backyard or courtyard can be tilted up vertically, creating both extra space for another building and also retaining the same amount of landscape or bio mass. Green roofs and walls to preserve biomass Graeme Hopkins Hopkins.Graeme@saugov.sa.gov.au May 2008 South Australian Government Incentive Program: Bushtops for Green Roofs and Walls This concept can be taken further by adding another dwelling to the site and incorporating a green roof and living wall to increase the landscape/biomass along with the built form density. Developing this process even more, it is possible to increase the built form density and create more landscape/biomass than the site had in the pre- development stage. The advantages of this building technology are an increase of biomass and biodiversity, together with the expected environmental benefits to the building interior, and an increased capacity in stormwater retention and detention of the site via the bushtop roofs and walls. The downside is a loss of deep root zone for large trees and ground infiltration of stormwater. Some of the landscape/biomass areas may not be usable for active open space as it is vertical or an extensive (and therefore non-accessible) roof system, the need for recreational open space will have to be accommodated elsewhere in the development or as part of an integrated public open space system. Program South Australian Government buildings or projects and projects financed by the State Government can access design services for concept design and development for bushtop green roofs and walls. This will be a free professional design service for these projects. Planning SA’s program includes unique green roof and living wall incentives for Government buildings and projects. Often with many Government agencies, monies for incentive programs are limited and very competitive, so a pioneering idea may have very little leverage to attract funding. However, under this new incentive program, Government projects can now access design and development services via Planning SA’s Principal Urban Designer's expertise in green roof and living wall design. This is a free service for government projects to encourage the inclusion of green roofs and walls into their sustainable projects; an effective way to incorporate this green technology into new buildings or revitalisation projects. This concept design and development service may range from informed advice at the conceptual stage of a project through to the full conceptual design and development documentation of a green roof or living wall system prior to construction documentation. The construction documentation will be carried out by the Government agency or their consultant. Technical advice may be provided during the construction documentation stage and the implementation of the bushtops. The unique nature of this incentive program is that Government agencies/client groups have no additional costs for concepts and designs, and that Planning SA has no extra costs, this depends on that Planning SA has the technical knowledge to provide this service. The Government can lead by example by developing demonstration projects without a design cost penalty. A major spin off from the demonstration projects is the influence that this will have on the private sector in the competitive sustainable green building market. As Government projects push the boundaries in the sustainable world and demand higher green ratings for their leased spaces then the commercial sector with respond with green building advancements. Current Projects A stepping stone corridor is being planned to build on from the successful Hocking Place Bushtop project on a State Government housing development and the neighbouring private development of the Christies Walk rooftop. By linking a series of green roofs Graeme Hopkins Hopkins.Graeme@saugov.sa.gov.au May 2008 South Australian Government Incentive Program: Bushtops for Green Roofs and Walls across the city to connect with the surrounding parklands, habitat opportunities will be provided for a range of species. Planning SA is investigating the technology of bushtop roofs and walls to maintain or increase open space and landscape/biomass in the increased residential infill density program. This techology will become one of the many techniques used to increase density and livability in the inner metro. The bushtop roof and wall program will become the most visible and environmentally important of all the techniques employed. The bushtop for green roofs and walls program has already been implemented in several other Government city-wide projects that are in the conceptual development stage, including the new State Government Margery Jackson-Nelson Hospital featuring green roofs and walls integrated into various levels, as part of the sustainable design content required by Government. A high profile project that has State and Federal Government funding and incorporating the bushtop program, is the New Entry and Administration complex to Adelaide Zoo that features a long living wall leading into the Entry and transitioning from a living wall into a series of green roofs. This complex is being designed by Hassell. Adelaide Zoo new development designed by Hassell Flow-on Effect in Government and Local Government There is a natural flow-on effect from this incentive program to other levels of Government, such as Local Government. Like all organisations Local Government wants to be seen at the cutting edge and providing the best outcome for their rate payers. So as Government encourages the bushtop program, Local Government takes up the concept as well. An example is the development of a green infrastructure project for University of South Australia and partnered by Adelaide City Council, which was developed and brokered by Planning SA using this incentive program. This project would not have developed without the incentive program, which has provided expertise Graeme Hopkins Hopkins.Graeme@saugov.sa.gov.au May 2008 South Australian Government Incentive Program: Bushtops for Green Roofs and Walls and time developing this multi-layered green infrastructure, with living walls and green roofs forming a vital component of this urban ecosystem. Adelaide City Council has already produced a Fact Sheet on Green Roofs for Medium Density Housing and, combined with the bushtop program, these devices can be targeted to Government housing in the Adelaide City Council area to encourage the further development of green technology. Adelaide City Council fact sheet Catalyst for Private Sector These Government incentives are creating a catalyst for private development of green roofs and walls. By Government providing incentives it demonstrates that it is taking seriously the benefits of this technology for urban development, and this will gradually infiltrate into mainstream design of sustainable green buildings. Also this gives these projects a competitive advantage in their position in the sustainable green building market, including benefits to the Government leasing policy. Developers are starting to see advantages of these green technologies and are incorportating them into their buildings, as evidenced by the College Street Apartments at the Adelaide beachside suburb of Glenelg, designed by Woods Bagot for Urban Construct. Graeme Hopkins Hopkins.Graeme@saugov.sa.gov.au May 2008 South Australian Government Incentive Program: Bushtops for Green Roofs and Walls New development at Glenelg designed by Woods Bagot Conclusion It is important that Government takes on a leadership role in these new technologies in the sustainable green building industry. This leadership, especially by example, sends a powerful message to the community and industry that Government is serious about sustainability and climate change. This program is innovative in the way it uses avaliable resources within Government, and especially by not requiring extra capital expenditure.