Urban Heat Island Effect

Urban Heat Island Effect

Image 5: Urban heat by SA2 by for 2018. Source: DELWP, 2021, Spatial Data mart.

Urban heat is increasingly becoming an issue for the health and wellbeing of the community, particularly during periods of extended hot days. This is where the hard surfaces of an urban environment store the heat from the sun’s rays, then re-radiate it out at night-time. When occurring at a scale large enough e.g. suburb, municipal or city scale, the radiated heat keeps night-time temperatures higher for longer. This has well researched impacts on human health and wellbeing but also on our urban environments.

The most effective way of mitigating this heat is to reduce the amount of hard surfaces that receive direct sunlight through the natural shading of tree canopies. Increasing the amount of stormwater infiltrated into urban soils also helps to cool the urban environment by providing soil moisture to vegetation to create evapotranspiration.

Therefore, understanding where these heat impacts are greatest, gives us the ability to target these areas for greater tree canopy cover.

In Hobsons Bay, these hotspots occur around Altona Meadows, Seabrook and in the industrial parts of the Municipality. The Altona Meadows and Seabrook hotspots are the most concerning as they cover the majority of the residential areas in those suburbs. These areas are consequently also the areas with lowest tree canopy cover.