Evolvement was given the job to test a cost effective and zero water system for a new public building project. The idea was to trial green roofs without an irrigation system. The building in question will emit a volume of water from its air-conditioning, and this will be distributed to the roof via a wicking bed system developed by E2Designlab.
The green roof system provides a sustainable water source with zero town water. It will save the considerable cost in irrigation pipes, contollers and water. it will be maintenance free, failure will not be possible - a real plus for the green roof industry.
CLOUSTON associates, the project leads, required testing to see how the system would perform on green roofs. A variety of plants were chosen for their diversity. Two succulents, Australian native grasses and a 2 small shrub species. Plants were propagated by Evolvement Pty Ltd at their specialised green roof nursery. 5 types of green roof plots were trialled at different growing media depths with a number of replicates. Control green roof replicates provided a comparison to the wicking bed systems.
Media was provided by Benedicts Sand & Soil and Urbanscape from Knauf Insulation was included. Trials were conducted at the Evolvement research facilities in Sydney.
Growth rates and species survival were observed in the different plot types. Records of plant mass and survival were kept for a 12 month period during all seasons.
The interesting aspect of this research is that the wicking bed plots have no piped irrigation. The system is fed by normal humidity extraction from air conditioners in the building. Two types of wicking bed systems were used. One based on sand and the other on a 40mm Urbanscape Greenroll layer. Traditional drip irrigation was also used to compare performance. Plants were periodically deprived of water to check limits of their performance.
I’m pleased to say that the wicking bed systems worked extremely well and had no detrimental effect on the plants. In fact the plant roots obtained water from the wicking beds directly. When compared to control plots, wicking bed plant growth and species survival had a marked improvement.
Urbanscape wicking bed plots had similar or better results with an added advantage of minimal media depth and green roof weight. For instance, Urbanscape Greenroofs weighed 100kg/M2 less than the sand-based system. This of course means your building can be constructed with lighter and cheaper roofing systems.
Thank you Clouston and E2Design for your creative approach and the trust you gave Evolvement Pty Ltd to provide the required research.
If you want to have more information, or research on your ideas contact our specialised research team on 0468 787 071 or rob@greenlook.com.au
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