Urban Intensification, Biophilic Design & SW Management in SEQ. Understanding Blue Green Roofs.

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  • The Blue Green roof combines blue and green roof technologies. Conventional green roofs use a drainage layer to provide lateral drainage and irrigation. Blue roof technology, however, aims to increase both the volume of water stored and control the amount of water released.
  • Combining the technologies can increase the overall benefits of greening roof-scapes.
  • Combining blue green roof technology and encouraging the wide spread adoption would mitigate flood events and better manage storm water runoff in SEQ.
  • Blue Green roof tops will capture and slowly release rainwater in order to slow the rate of runoff and reduce the potential for related flooding.
  • During and after rainfall, weirs at roof drain inlets restrict the flow rate of the captured water, creating temporary ponding before gradually releasing stormwater to the main SW system. Most weirs allow for adjustment of the flow rate.
  • The ratio of captured runoff is typically designed to closely mimic the pre-construction hydrology of the site. A blue roof acts as a temporary sponge, replacing the prior capacity of undeveloped, pervious ground to absorb rainwater.
  • The stored rainfall can be reused for irrigation purposes, as makeup water for cooling, or in recreational contexts for communal spaces.
  • Blue roofs are often incorporated with extensive green roofs to provide hydration to vegetation.
  • Blue Green Roofs reduce or eliminate the need for underground storage, which in turn reduces excavated material and underground construction cost and time.
  • Roof top Gardens will increase real estate value, biodiversity, rainwater management and re-use, building energy performance, urban resilience, human health or reduction of the urban heat island effect.

Glossary of Green Roof Types

Extensive

Extensive green roofs are lightweight with a shallow layer of growing substrate of less than 200 mm deep -  Generally groundcovers, sedums and grasses.

Intensive

Intensive green roofs are intended to replicate what can typically be found at ground level in the natural landscape, and in green spaces such as parks or cultivated gardens. (A deeper or intensive growth medium substrate is greater than 200mm, to accommodate plants with deeper root zone requirements).

Semi Extensive

A semi-extensive green roof is a hybrid of the two systems (extensive and intensive). Allowing a combination of both shallow and deeper planting requirements.

Recommendations

  • Government to create specific Green Infrastructure funding Grants for Roof tops.
  • Incentives to developers to adopt Green & Blue Roof Initiatives via tax concessions.
  • Incentives to developers through Increased building height approvals which would raise floor space yield ROI and counter balance any upfront costs associated with provision of green (blue) infrastructure.
  • Approval relaxations on Site Cover ratio, Car Park Spaces required, sub-grade SW retention requirements when sustainable Blue Green Roofs are design and Installed.
  • Mandated Green (Blue) Roofs in High Density Inner City precincts under certain Neighbourhood plan policy / City Plan 2014.

 

James Worth, Director of Worth Design, June 2018

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Using WSUD to Drive Innovation in Open Spaces

INTERNATIONAL PARKS AND LEISURE CONGRESS

MELBOURNE CRICKET GROUND, MELBOURNE, AUSTRALIA.

14-17 OCTOBER 2018

#IPLC2018

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ABSTRACT

When planning and designing new sporting facilities, as well as renewing existing green open space, it is important to consider how Water Sensitive Urban Design (WSUD) can effectively address urban storm water runoff.

Sporting facilities and the broader network of green open spaces are of increasing importance as high density development significantly reduces stormwater infiltration and aquifer recharge. 

Apart from the benefits to public health and livability, sports and recreational open space will play an increasingly important role in managing urban runoff and mitigating the effects of the urban heat island.

A multi-disciplinary, WSUD integrated approach to planning and design, will achieve outcomes that provide usable open space, attenuate peak flows associated with urban runoff, reduce mains water irrigation demand, treat polluted storm-water and  provide urban cooling.

 

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Sally Boer

Sally Boer is a Director of E2Designlab, who has been at the forefront of WSUD and passive irrigation, successfully delivering the first sports field wicking bed in Australia.  She brings ecological first principles and integrated design processes into practice to deliver multiple benefits. 

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Christoper Walker

Dr Christopher Walker is the Environmental Manager of Covey Associates and has developed and managed stormwater treatment projects for numerous development projects in Australia and overseas. Chris is also an Adjunct at the University of the Sunshine Coast and a founding member of the Stormwater Research Group at USC.

 

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Terry Lucke

Dr Terry Lucke is Associate Professor in Hydraulic and Civil Engineering at the University of the Sunshine Coast in Australia. His main teaching areas are Fluid Mechanics, Hydraulics and Road and Drainage Design. The focus of Terry’s research includes the development of innovative stormwater management systems and evaluation of their performance, and the advancement of Water Sensitive Urban Design practices. Terry leads a team of researchers in the Stormwater Research Group at the University of the Sunshine Coast.

 

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James Worth

James Worth is a Senior landscape Architect and Director of Worth Design who's passion is in delivering future solutions that cater to sustainable design outcomes. Such innovations aim to provide positive solutions that will minimise negative impacts of increased urban density. Worth is extremely passionate about Green Infrastructure and especially living architecture biomass allocation within high density built up spaces. 'Clean air and clean water will be increasingly important in future urban environs and therefore it is vital that we plan now with realistic cost effective and practical sustainable solutions in mind'.

 

https://www.iplc2018.com/

 

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