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The irrigation cooling effect at the Royal Botanic Garden Melbourne and Cranbourne. Cho Kwong Charlie Lam, Ailie Gallant, Nigel Tapper. Nocturnal irrigation alleviates urban heat island. Potential 1-2°C cooling. modified after City of Melbourne 2012.
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The irrigation cooling effect at the Royal Botanic Garden Melbourne and Cranbourne Cho Kwong Charlie Lam, Ailie Gallant, Nigel Tapper
Nocturnal irrigation alleviates urban heat island Potential 1-2°C cooling modified after City of Melbourne 2012
Reducing 1-2 °C at night saves lives during heatwaves Threshold Temperature This morning’s minimum Nicholls et al. 2008
Identify neighbourhoods that require intervention A = Moderate priority B = Medium priority C = Highest priority Norton et al. 2015
Hourly-avg Ta data 18/12/13 – 26/3/14 O Gate (ref.) Fern Gully Oak Lawn
Cranbourne Garden Ian Potter Lawn Desert Discovery Camp (ref.) Bloodwood Garden Hourly-avg Ta data 18/12/13 – 26/3/14
Well-irrigated areas were 2-4 °C cooler than non-irrigated areas during heatwave Melbourne Garden Hot Ta average of 12-4pm, 14 – 17 January 2014 (Tmax > 41 °C) Warm
Nocturnal irrigation cooling and residual daytime cooling Positive values indicate cooling. Ta difference: O Gate – Oak Lawn Average of 10 irrigation events
Irrigation intensified nocturnal cooling during heatwave Heatwave days: Ta ≥ 35 °C (n = 3) Ta difference: O Gate – Oak Lawn
Limited nocturnal cooling effect when daytime misting systems were used Average of 10 irrigation events Ta difference: O Gate – Fern Gully
Lawn surface produced 1-2 °C nocturnal cooling Average of 15 irrigation events Ta difference: Desert Discovery Camp – Ian Potter Lawn
Gravel surface had negligible irrigation cooling effect Average of 16 irrigation events Ta difference: Desert Discovery Camp – Bloodwood Garden
Prioritising the landscape zones that require additional mitigation 10 0 Well-being nodal space Very poor Very positive
Incorporating water-sensitive urban design in cooling sculptures for heat respite Breeze shelter in Singapore Misting system
Summary Irrigation cooling effect differed between two gardens with distinct characteristics Greater irrigation cooling effect during heatwaves Consider shifting irrigation timing
Landscape coefficient determines irrigation priority Connellan 2013