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Moderating the urban heat of car parks in Moreland

March 29, 2022 at 12:00 am John Englart 1 comment

As a highly built up municipality Moreland tends feel the heat of Summer and extreme heat events exacerbated by the urban heat island effect. The extensive car parks and roads around our municipality contribute to this amplification of high temperature effects.

New research from University of Western Sydney throws new light on the urban heat island effect on microclimates and especially the role of asphalt car parks. Asphalt is particularly bad for building up heat inertia to warm the micro climate during both the day and night. But the researchers also outlined solutions.

How does this apply in Moreland? Well Moreland Council should be implementing heat mitigation solutions for all Council car parks, and also advocating for these solutions when Businesses provide parking, or the State Government expands parking, such as at Merlynston Station. Moreland Council is expanding parking at Hosken Reserve as part of the Hosken Reserve Masterplan, but have paid little attention to limiting urban heat from car parking. When putting in new car parking is the ideal time to implement urban heat solutions.

The growing number of unshaded car parks, particularly on the urban fringe, is a symbol of our failure to create communities fit for the 21st century. They reflect an unwillingness to stop out-dated and unsustainable urban sprawl and associated car-dependency.
Worse, these spaces will be with us for decades. In a warming world, improving the design of new and existing car parks is essential. Regulations and guidelines need updating. Shadeless, heat-radiating car parks must become relics of the past. We have the necessary technology. We don’t need to wait. We need to change”.

Limiting the warming effect of urban expansion is possible. It requires dedicated heat responsive planning and design strategies being applied systematically and at scale. But where should planners and developers start to effectively reduce urban heat?

At-grade car parks are an ideal starting point. They represent the ‘low-hanging fruit’ for urban cooling efforts. While unavoidable today and in the near future, at-grade car parks are predominately unshaded; made from black, heat-retaining asphalt; widespread and fairly uniform; and often large in size. Changes to current designs of at-grade car parks can therefore have a big impact. A number of strategies to effectively reduce surface heat of car parks are commercially available. Cooling car parks not only addresses their status as local heat islands, but it also leads to lower ambient air temperatures in downwind environments. 

Dr Sebastian Pfautsch et al in Despicable Urban Spaces: Urban Car parks (Feb 2022)

The report goes beyond highlighting the problem of urban heat. It also proposes solutions. The most effective cooling techniques for car parks will:

• Reduce the area covered by impermeable black asphalt
• Coat remaining asphalt with reflective surface sealants
• Increase open space (permeable pavements)
• Use solar reflective (light-coloured), porous surface materials
• Use existing tree canopy for shade cover
• Introduce infrastructure for strategic shading
• Use climate-adapted trees species with wide, dense crowns
• Irrigate green infrastructure (active or passive)

“Shade in car parks will also reduce exterior and interior temperatures of parked cars. This effect will lead to reduced emissions as less fuel is required to cool interior air and surface temperatures to safe and comfortable levels.”

Further-reaching measures to reduce the impact of car parks on urban microclimates include:

• Using solar panels to shade car parks, with the added benefit of generating renewable energy.
• Green/living facades for multi-level parking lots.
• Infrastructure for active and public transport to limit car-use
• Occupancy surveys to identify optimal car park size and available space for cooling mechanisms
• Transforming unused car parks into green spaces/parks
• Increase smart- and shared-parking options (private and business).

“The interrelated impacts of global warming and increasing urban expansion on heat in metropolitan regions, and the positive relationship between growing urban populations and at-grade car parking points towards acceleration of urban warming. This report offers alternatives to avoid this scenario, by transforming car parks from heat islands to cool islands.”

The report highlights a failure in the current Australian standards and state based standards around urban heat of infrastructure. It finds there is no obligation for government infrastructure projects or private development to implement heat-responsive design elements when constructing at-grade car parks.

A lack of appropriate incentives to implement energy efficiency measures could significantly hinder the realisation of progressive and effective heat mitigation strategies. Competing budgetary priorities, upfront capital costs, desired payback periods, and difficulties measuring wider public and environmental benefits, along with split incentives, seem to be the primary reasons as to why heat mitigation solutions have not been implemented.

Despicable Urban Spaces: Urban Car parks (Feb 2022)

Moreland Council is working on addressing urban heat, including in playgrounds. A shade sail has just been installed over part of the Skatepark at CB Smith Reserve in Fawkner. This will keep the shaded concrete cooler during extreme heat days. Well done Moreland Council.

Of course all the asphalt car park to the south and much to the east and west of the Skatepark will still be exposed to the sun. There is some canopy shade but not nearly enough. And the John Fawkner College synthetic Sports field adds to the urban heat in the micro-climate for the area during Spring, Summer and Autumn (See Literature Review on Synthetic Turf Chapter 5 on Urban Heat Island Impact, and the Climate Action Moreland fully referenced and detailed blog on synthetic turf and urban heat island impact in the context of Hosken Reserve.)

Vegetation, Urban heat and heat vulnerability in Moreland

Victorian Planning Department of DELWP has an interactive mapping tool for Melbourne. This brings together three main datasets: vegetation cover, urban heat, and the heat vulnerability index. It contains data only from 2014 and 2018. It Really needs to be updated to include 2022 data.

Urban heat vulnerability adds in social demographic factors to urban heat to add a vulnerability rating. This includes such factors as population age, education, language and migrant background, health data, socio-economic status, which can all influence vulnerability and heat health status.

We know that vegetation, and particularly provision of canopy shade can reduce urban heat.

It is interesting looking at the change in vegetation between 2014 and 2018. It would be even better if we could compare 2018 to 2022, but there is no recent data, unfortunately.

From this mapping tool it appears there has been a slight greening between 2014-2018, but much of the municipality has remained fairly static, while there are even some places that show a vegetation loss. In recent years Moreland Council have increased tree plantings in public areas, but vegetation is being lost at a greater pace on private land predominently due to subdivision and urban infill development.

Reference:

• Pfautsch S., Wujeska-Klause A., Paolini R., van den Nouwelant R., Morrison N. (2022) Despicable urban places: hot car parks. Western Sydney University, 68p. DOI: 10.26183/7q7a-f148 URL: https://doi.org/10.26183/7q7a-f148
• DELWP, Victoria Planning. Cooling and Greening Melbourne Interactive Map. Bringing together three main datasets: vegetation cover, urban heat, and the heat vulnerability index Contains data from 2014 and 2018. Really needs to be updated to include 2022 data. https://www.planning.vic.gov.au/policy-and-strategy/planning-for-melbourne/plan-melbourne/cooling-greening-melbourne/cooling-and-greening-melbourne-interactive-map

Entry filed under: climate change info, Moreland Council, news. Tags: asphalt, car park, climate adaptation, Fawkner, Hosken Reserve, Merlynston Railway Station, shade sail, synthetic turf, Urban heat island, urban heat island effect.