The Role of Carparks As Urban Heat Islets in Western Sydney

Home , Jamisontown, Old Toongabbie, Parklea, Western Sydney Parklands

The role of carparks as urban heat islets in

Chanda Prajapati June 2020 A thesis submitted in fulfillment of the requirements for the degree of Master of Research Western Sydney University

Supervisor Dr. Sebastian Pfautsch

Statement of Authentication

The work presented in this thesis is, to the best of my knowledge and belief, original except as acknowledged in the text. I hereby declare that I have not submitted this material, either in full or in part, for a degree at this or any other institution.

…………………………………………………….. (Signature)

Acknowledgment

I would like to express my sincere gratitude and thankfulness to my Supervisor, Dr. Sebastian Pfautsch, for his continuous support, guidance, patience, and invaluable assistance. I could not have imagined having a better advisor and mentor for the completion of my Master of Research. I am very much grateful for support and encouragement since tentative conversations about the possibility of undertaking a master’s research project, during my physical hard times to the end of the project.

I would also like to thank Susanna Rouillard, GIS, and Data Visualisation Specialist for helping me in producing a GIS map. I am also thankful to Amrita Limbu, a Ph.D. scholar of Western Sydney University for constant support during the writing process.

I owe a very special thanks to my parents (Krishna Bhakta and Churi Prajapati) and in-laws (Shyam and Laxmi Awale) for all their encouraging words throughout this journey. I would not have completed this road without their undeniable support of caring and nourishing my one-year-old son Kiaan.

Finally, I appreciate the patience of my husband Kiran Awale, and his immense belief that I can complete this study. His endless care and support mentally and financially will always be remembered. Thank you for your unending love and support. I couldn’t have done this without you.

Abstract

Every summer, and at an increasing frequency and severity, residents of western Sydney experience extreme heat during the day and heat island effects during the night. The latter results in higher nighttime air temperatures in urban areas compared to nearby rural land. This phenomenon is linked to low vegetation cover and a large proportion of hard surfaces from buildings, roads, and carparks that dominate urban landscapes. Especially the dark, flat and unshaded surfaces of car parks store and re-radiate large amounts of solar energy and contribute substantially to local heat. The contribution of carparks to urban heat island effects and localised warming is well documented in the literature. Yet, the area taken up by these local heat islets in western Sydney remains unknown.

This research quantified the current (2019) total area of carpark infrastructure across all suburbs that are contained in six local government areas (LGAs) in western Sydney. For the purpose of this study, carparks were defined as those exposed to solar radiation, thus excluding underground carparks and lower decks of multilevel carparks. Carparks with less than 10 parking bays were also excluded as their contribution to local warming was deemed insignificant. All carparks were remotely measured using high-resolution aerial images. In addition, changes in carparking space between 2010 and 2019, as well as the presence and extent of green infrastructure and tree shade provided in these carparks were determined. Lastly, the relationship between the dynamics of changes in carpark area and changes in the size of local populations were elucidated for each suburb in each LGA using Census data (only available for 2012 and 2018 during the time of this research).

Image analyses resulted in the identification of 2250 carparks across a total area of 1300 km2 of urban and rural land covered by 143 suburb areas. Carpark surfaces were predominately (>90%) made from conventional black asphalt and far less from light-coloured concrete. The total area covered by car parks across this land increased by 21% from 4.8 km2 in 2010 to 5.8 km2 in 2019 while at the same time the total population increased 16%, from 1.12 million to 1.31 million people. The largest increase of carpark area was observed for the LGA of Blacktown, where 144 new carparks added 47 ha (+46%) of sealed black surface, nearly all of which was unshaded. At the same time, the population of Blacktown increased only by 15% (317,766 in 2012 to 366,379 in 2018). The largest increase in carpark area relative to the area of the LGA was in Camden where on average across all suburbs, carparking space grew by more than 50%. The area covered by carparks decreased only in the LGA of Parramatta City.

In 2010, 3880 trees and other green infrastructure covered just 0.98% of the carparks in the six LGAs. By 2019, and as a result of the increasing total area of carparks, the proportion of green infrastructure remained just above 1%, even though the total number of trees counted in the carparks had risen to 4471. There was a highly significant (p <0.001) and positive relationship between the area covered by carparks in individual suburbs of the six LGAs and the number of trees growing in these carparks in 2010 and 2019.

To document the capacity of tree shade to reduce local heat in carparks, additional empirical measurements of surface, air, and black globe temperatures (the latter as an approximation for a ‘feels like’ temperature) were collected in four carparks during sunny days in summer 2019/20. In all four carparks, measurements were collected in full sun and under tree shade on black asphalt. Tree shade reduced surface temperatures by 15-20℃, air temperature by 2-5℃, and black globe temperature by 5-10℃. iii

The results of this study reveal the extent and dynamic changes of carparks in western Sydney. It is reasonable to expect that the increasing space used by carparks intensifies local heat in a part of the Sydney Basin that already experiences record temperatures in summer. This expectation is enforced by the finding that these carparks only contain 1% green infrastructure, and shade is provided by just 8 trees per 10,000 m2. Moreover, the overcapacity of current carparking space, where the relative expansion of this space markedly exceeds population growth in some LGAs is of great concern. Is capacity being built for anticipated growth in population, or is greenfield converted to unnecessary grey infrastructure? In any case, negative effects on summer heat remain.

Rapid urban development in western Sydney is predicted to continue for the coming decades. Homes, work and transport infrastructure for an additional 800,000 residents must be provided by 2036. New insight offered through this research about the dynamic relationship between concurrent increases of local populations and carparks can now be used to develop more sustainable strategies to provide the required parking infrastructure. The data presented here make it obvious that regulators, urban planners, contractors, and land managers have failed to address the issue of increasing urban heat loads through carparks in the past decade of development in western Sydney. Hence, this research work can become a central point of reference to inform responsible infrastructure planning across the region.

Heat in western Sydney is a regional issue that requires concerted solutions. As car dependency remains large in this region, carparks are a seemingly unavoidable source of radiant heat for some time to come. This situation demands that new and improved policies and regulations are developed that result in the construction of carparks that mitigate heat much better than today. In the meantime, local governments can ramp up their greening programs for carparks to improve the microclimate around these heat islets and increase the thermal comfort of their users.

Contents 1 Introduction...... 1 1.1 Background ...... 1 1.2 Heat in Western Sydney ...... 8 1.3 Car Dependency ...... 9 1.4 Carparks as Sources of Urban Heat ...... 10 1.5 Thesis Overview ...... 12 2 Materials and Methods ...... 14 2.1 Study Areas ...... 14 2.2 Carpark Assessments ...... 16 2.3 Demographic Data ...... 20 2.4 Carpark Heat ...... 20 2.5 Statistical Analysis...... 21 3 Results...... 23 3.1 Overview ...... 23 3.1.1 Demographic Status ...... 23 3.1.2 Carpark Types ...... 23 3.1.3 Carpark Area ...... 25 3.1.4 Green Infrastructure ...... 27 3.1.5 Population and Carpark Dynamics ...... 29 3.2 Heat in Carparks ...... 31 3.3 Individual Councils ...... 34 3.3.1 Blacktown ...... 34 3.3.2 Campbelltown ...... 38 3.3.3 Camden ...... 42 3.3.4 Cumberland...... 46 3.3.5 Parramatta ...... 49 3.3.6 Penrith ...... 53 4 Discussion ...... 58 4.1 Trends across Western Sydney ...... 58 4.2 Consequences of Missing Shade in Carparks ...... 65 4.3 The Future of Carparks ...... 68 4.4 Limitations of this Study ...... 69 4.5 Impact Statement ...... 70 5 Conclusion ...... 71 6 References ...... 72 7 Supplementary Figures………………………………………………………………………… 82

Tables Table 2.1: Key categories, attributes, and units assessed for each carpark...... 17 Table 3.1: Demographic status and size of six local government areas (LGAs) in western Sydney. ... 23 Table 3.2: Overview of the number and size of carparks across all suburbs of the investigated LGAs in western Sydney for the years of 2010 and 2019...... 25 Table 3.3: Variation in the ratio of carpark space relative to suburb size among the six LGAs between 2010 and 2019...... 26 Table 3.4: Total area of green infrastructure, number of trees and the ground area shaded by trees in carparks of six western Sydney LGAs for 2010 and 2019...... 27 Table 3.5: Status of trees (Number and area) in each Study site of studied LGA ...... 28 Table 3.6: Carparks, population, and their change between 2010 and 2019 across the suburbs of Blacktown ...... 36 Table 3.7: Status of Green Infrastructure in the Blacktown carpark in 2010 and 2019...... 37 Table 3.8: Carparks, population, and their changes between 2010 and 2019 across the suburbs of Campbelltown...... 40 Table 3.9: Status of Green Infrastructure in the Campbelltown carpark in 2010 and 2019...... 41 Table 3.10: Carparks, population, and their changes between 2010 and 2019 across the suburbs of Camden ...... 44 Table 3.11: Status of Green Infrastructure in the Camden carpark in 2010 and 2019...... 45 Table 3.12: Carparks, population, and their changes between 2010 and 2019 across the suburbs of Cumberland ...... 47 Table 3.13: Status of Green Infrastructure in the Cumberland carpark in 2010 and 2019...... 48 Table 3.14: Carparks, population, and their changes between 2010 and 2019 across the suburbs of Parramatta ...... 51 Table 3.15: Status of Green Infrastructure in the Parramatta in 2010 and 2019...... 52 Table 3.16: Carparks, population, and their changes between 2010 and 2019 across the suburbs of Penrith ...... 55 Table 3.17: Status of Green Infrastructure in Carpark of Penrith in 2010 and 2019 ...... 56

Figures Figure 1.1: Representation of the Urban Heat Island Effect...... 1 Figure 1.2: Factors influencing the intensity and formation of UHI...... 4 Figure 1.3: A representation of the sources and interactions that lead to rising air temperatures in urban environments ...... 5 Figure 1.4: Examples of different pervious surface materials...... 7 Figure 2.1: Map of western Sydney with the six studied local government areas marked with red lines...... 15 Figure 2.2: Image showing an area of Marsden Park, LGA of Blacktown...... 16 Figure 2.3: Measuring area of car park and tree crown area of Western Sydney university P’south ... 17 Figure 2.4: Examples of conventional carparks with little or no green infrastructure in 2019...... 18 Figure 2.5: Examples of conventional carparks with noticeable proportions of green infrastructure, especially tree canopy...... 19 Figure 3.1: Relative proportion of different types of carparks analysed in the present study...... 24 Figure 3.2: Surface materials used in carparks of the six western Sydney LGAs ...... 24 Figure 3.3: Relationship between the population of the six investigated LGAs and the area covered by carparks...... 27 Figure 3.4: Relationship between the total area of carparks in suburbs of the six LGAs...... 29 Figure 3.5: Dynamics of population and carpark attributes based on observed changes between 2010/2012 and 2018/2019 across 143 suburbs in six western Sydney councils...... 30 Figure 3.6: Mean air temperature (panel a) and mean black globe temperature (panel b) of four conventional asphalt carparks in western Sydney...... 31 Figure 3.7: Mean surface temperatures of four conventional asphalt carparks in western Sydney.. ... 32 Figure 3.8: Examples for the effect of direct sunshine and shade on surface temperatures of black asphalt carparks in western Sydney...... 33 Figure 3.9: Location of carparks across the LGA of Blacktown...... 35 Figure 3.10: Relationship between population growth between 2012 and 2018 and the change in carparking area from 2010 to 2019 across the 30 suburbs of Blacktown ...... 38 Figure 3.11: Location of carparks across the LGA of Campbelltown...... 39 Figure 3.12: Relationship between population growth between 2012 and 2018 and the change in carparking area from 2010 to 2019 across the 24 suburbs of Campbelltown...... 42 Figure 3.13: Location of carparks across the LGA of Camden...... 43 Figure 3.14: Relationship between population growth between 2012 and 2018 and the change in carparking area from 2010 to 2019 across the 12 suburbs of Camden...... 45 Figure 3.15: Location of carparks across the LGA of Cumberland ...... 46 Figure 3.16: Relationship between population growth between 2012 and 2018 and the change in carparking area from 2010 to 2019 across the 13 suburbs of Cumberland...... 49 Figure 3.17: Location of carparks across the LGA of Parramatta...... 50 Figure 3.18: Relationship between population growth between 2012 and 2018 and the change in carparking area from 2010 to 2019 across the 27 suburbs of Parramatta...... 53 Figure 3.19: Location of carparks across the LGA of Penrith...... 54

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Figure 3.20: Relationship between population growth between 2012 and 2018 and the change in carparking area from 2010 to 2019 across the 28 suburbs of Penrith City...... 57 Figure 4.1:The transformation of the suburb of Jordan Springs in the LGA of Penrith...... 59 Figure 4.2: An example for the decrease in carpark space at Wentworth Point, a suburb in the south- east of the LGA of Parramatta City LGA...... 60 Figure 4.3: Relationship between urban population density and fuel use per capita for large metropolitan centres around the world...... 62 Figure 4.4: Berkeley Lab researchers measuring cool pavement technology to mitigate the negative effects of UHIE ...... 64 Figure 4.5: Example of porous parking surface materials...... 65 Figure 4.6: Changes in carparking area. Blacktown Showground, Richmond Rd, Blacktown NSW 2148, Australia...... 69 Supplementary Figure S1: Blacktown LGA with its delineated suburbs……………..……………….82 Supplementary Figure S2: Campbelltown LGA with its delineated suburbs…………………………..83 Supplementary Figure S3: Camden LGA with its delineated suburbs………………..……………….84 Supplementary Figure S4: Cumberland LGA with its delineated suburbs……………………………..85 Supplementary Figure S5: Parramatta LGA with its delineated suburbs……………..………….……86 Supplementary Figure S6: Penrith LGA with its delineated suburbs……………….…………….…...87

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1 Introduction

1.1 Background

Urban heat island effects (UHIE) arise when urban areas experience significantly warmer air temperatures compared to nearby rural areas (Figure 1.1). These temperature differences are most pronounced during the night and have been known for many decades (Duckworth & Sandberg 1954; Nieuwolt 1966; Sundborg 1950). UHIE is a relatively local climate phenomenon where air temperature of urban areas is usually 3-4 °C warmer compared to their rural proximities, though peak differences can reach 10 °C or more (Heaviside, Cai & Vardoulakis 2015). The term ‘urban heat island’ was introduced by Hutcheon (1967) to describe this phenomenon and it was further verified in ground-breaking studies (Kim 1992; Oke 1973, 1976, 1981; Oke & Maxwell 1975). Since that time thousands of studies describing UHIE have been published and UHIE have been confirmed for hundreds of cities around the world (Peng et al. 2012; Santamouris et al. 2015).

Figure 1.1: Representation of the Urban Heat Island Effect. Generalised variation of air and surface temperatures are shown for day and night along a rural-urban-rural gradient. Image sourced from the Environmental Protection Agency, United States (http://www.epa.gov/heatisland/about/index.htm).

Urban development replaces natural, open surfaces with dry, hard, impervious surfaces such as roads, carparks, footpaths, roofs, and buildings. Removal of vegetation and associated loss of shading and cooling benefits greatly impacts urban microclimates and it is this transition from green to grey urban infrastructure that leads to an increase in local surface temperature, 1 and subsequently to hotter air temperature and the observed UHIE (Coutts et al. 2010). The most impactful factors that lead to UHIE are (after Santamouris 2007): 1. low vegetation cover that results in low rates of evapotranspiration and associated cooling, 2. low albedo causing absorption of solar radiation, 3. interference with local air flows and 4. a high amount of anthropogenic heat release.

Negative Effects of Urban Heat There is international scientific agreement that air temperatures are increasing, and extreme temperatures occur more frequently and with greater intensity (IPCC 2019). Numerous studies have assessed the impacts of rising temperatures on urban environments (Gasper, Blohm & Ruth 2011; Ng et al. 2012; Santamouris 2014). The UHIE has numerous environmental problems along with substantial consequences for the liveability in our cities (Yang, Wang & Kaloush 2015). It impacts health, wellbeing, and thermal comfort of affected communities (Grimmond 2007). The continuing pattern of increasing air temperatures can lead to degraded urban climates where temperature extremes worsen. Therefore, the UHIE is an enormously important issue to address as more and more urban dwellers would be exposed to more and more extreme heat (Coutts, Beringer & Tapper 2010).

The negative impacts of extreme temperatures can be assigned to the three broad categories of public health, economic disruption, and environmental degradation. Heat leads to increased surface temperatures during the day, which will reduce nighttime cooling and the capacity of humans to recover from the daytime heat. If extreme daytime heat and associated high nighttime temperatures continue over more than 3-4 days, human health will be impacted widely, and general discomfort, heat cramps and exhaustion, heatstroke, and heat-related mortality are likely to spike (Margolis 2014).

Projected surges in summer temperatures and related illness and mortality rates have been identified as a serious health-related problem (Golden et al. 2008; Gubernot, Anderson & Hunting 2014; Luber & McGeehin 2008). For example, exposure to excessive heat kills more people each year compared to all other natural disasters combined in the United States

(MMWR 2006). Cities around the world operate heat alert systems (Weisskopf et al. 2002) including Melbourne in Australia (Nicholls et al. 2008).

The UHIE alone, but even more so in combination with high and extreme air temperatures increase urban energy demand for cooling (Founda & Santamouris 2017). Normally, for every increase in 0.6 ℃ temperature increase in summer time, electricity demand increases by 1.5- 2% (Akbari, Pomerantz & Taha 2001). Heatwave events are likely to amplify this effect, whereby additional stress is added to electricity grids, increasing the risk of black-outs. Black- outs triggered by extreme heat have the greatest impact on cities and urban populations that rely heavily on continued access to electricity to keep vital systems operative, including offices, health care, public transport, but also air conditioning and refrigeration.

Increasing urban heat applies stress on local, urban, and peri-urban ecosystems and wildlife. Once thermal limits are surpassed, faunal and floral species can be pushed outside their tolerance range (Valle-Díaz et al. 2009). Urban heat and the UHIE can also lead to degradation of water quality by thermal contamination due to increase of surface temperature. Rainwater that falls to the impervious surface of the city gets additional heat loads along with dust and chemicals (Finkenbine, Atwater & Mavinic 2000). The warmer and more polluted runoff drains into waterways where it affects the habitat quality and life cycle of aquatic organisms (Krause et al. 2004).

The global increase in urbanization and related effects of human consumption, land use change, and energy demand requires new, and most importantly sustainable adaptation and mitigation strategies for urban heat, including ways to limit UHIE. One such strategy relates to the use of reflective materials. While the positive effect of reflective materials to reduce surface temperatures and energy consumption in cities is well documented, it is not well understood how large-scale introduction of reflective materials would impact urban climate and also ecosystem functions (Yang, Wang & Kaloush 2015).

Factors Impacting UHIE The UHIE is influenced by uncontrollable and controllable factors (Figure 1.2). While the uncontrollable factors relate to geographic location, larger scale environmental processes (e.g., seasonal changes), and planetary cycles (e.g., day-night cycles), the controllable factors can be manipulated to influence the extent and intensity of UHIE. 3

Figure 1.2: Factors influencing the intensity and formation of UHI. Figure modified from Rizwan, Dennis & Chunho (2008).

A rapid increase in the world’s urban population is a key driver for UHIE. The global area occupied by cities continues to expand and at the same time cities become denser and lose vegetation cover. However, the direct impact of urbanisation on UHIE has been debated in the scientific literature. Some time ago, studies have reported a positive correlation between urbanisation and the UHIE (Huang, Ooka & Kato 2005), whereas other studies did question this effect (Kim & Baik 2004).

To date, overwhelming evidence has identified and quantified the direct impact of growing urban populations on local climate and UHIE (Ellis et al. 2017; Javanroodi & Nik 2020; Ramírez & Souza 2019). The impact of urbanisation on climate change has been documented for several Australian cities (Maheshwari et al. 2020). Results like these emphasize the importance to include urbanisation associated climate change, along with the effects of greenhouse gases, in emerging climate change adaptation strategies and policies. Growing urban populations contribute directly to more intense UHIE in two ways. First, activities of a growing urban population lead to more intensified sources of anthropogenic heat. These sources comprise stationary sources like electricity consumption by buildings, industrial and commercial activities, public lighting, human and animal metabolism and lastly fuel combustion from vehicular traffic (Déqué 2007; Ferreira, Oliveira & Soares 2011). Second, more buildings, roads, and other infrastructure will absorb and reradiate greater amounts of

4 solar energy (Figure 1.3). This energy can accelerate UHIE if it is trapped in urban space as a result of air pollution from intensified traffic and industry activities. In theory, the direct and indirect impacts of urban populations on UHIE should be controllable.

Figure 1.3: A representation of the sources and interactions that lead to rising air temperatures in urban environments. Image sourced from Yamamoto (2006).

Another controllable variable that indirectly contributes to UHIE is vegetation cover, or urban green infrastructure. Green infrastructure helps to cool by providing shade and through evapotranspiration of water (Mirzaei & Haghighat 2010; Zhang, Wu & Chen 2010). Shading lessens the surface temperature by reducing the extent of incoming and absorbed solar radiation. Evapotranspiration is a mechanism in which plants take up water from the soil and release this water as vapor through the leaves. The phase change of liquid water to vapor in the leaf produces cooling as it converts solar energy to latent heat.

Urban forests or parks usually have lower air and surface temperatures compared to the surrounding environment. Studies have shown that even relatively smaller green areas can have a marked cooling effect. A small park of 0.15 ha can generate about 1.5 ℃ mean air temperature cooling for about 100 m surrounding the park boundary and up to 3 ℃ cooling during midday (Shashua-Bar & Hoffman 2000). Further, it has reported that a large green area (156 ha) can generate a large cooling effect with maximum reductions of air temperature by 5.9 °C in summer (Upmanis, Eliasson & Lindqvist 1998). These studies demonstrate the 5 positive impact of urban green infrastructure to reduce heat and therefore limit the intensity of UHIE.

Buildings and roads are major contributors to UHIE through heat that is stored in their materials. However, the amount of storage and radiation of heat depends largely on the physical properties of materials that relate to reflectance, heat release, and heat capacity. Objects with high solar reflectance reflect most of the incoming solar energy and hence less heat is stored in the object (Chudnovsky, Ben-Dor & Saaroni 2004). As a rule of thumb, light coloured materials and objects reflect more energy than dark materials and objects. Dark materials have a low reflectance of 5-50%, which means that at least half of the incoming solar radiation is stored as heat. Importantly, the reflectance of building materials changes as a result of aging (Levinson & Akbari 2002). Not only the materials and colour but also the spatial arrangement and density of buildings can significantly impact the UHI by reducing or increasing the areas of exposed surfaces. The structure and width of urban canyons can impact the speed of airflow for natural ventilation and can provide shaded paths for pedestrians (Alobaydi, Bakarman & Obeidat 2016; Perini & Magliocco 2014).

Mitigation Strategies Mitigation of urban heat allows creating more habitable environments where thermal comfort is enhanced, and the energy consumption is reduced. Some of the widely recommended UHI mitigation techniques to moderate urban temperatures are cool materials, urban vegetation (green infrastructure), shading, and water sensitive urban design (WSUD). The effectiveness of these mitigation techniques can vary according to location, urban context (density, scale), and climate zone (Coutts et al. 2013).

Several building materials are major contributors to the development of UHIE, namely asphalt, concrete, stone, and brick – all materials with high thermal mass. The surface of these materials could be engineered to increase their reflectance, be shaded, or where possible be replaced with more thermally inert materials (e.g. wood or cladding). For example, cool pavement materials tend to store less heat compared with conventional products. Their increased reflectance (high albedo), emittance (high emissivity), and in case of some specific paving materials also their permeability or capacity to store moisture contribute to be a ‘cool’ alternative to common impermeable materials (Bretz, Akbari & Rosenfeld 1998). The use of lighter pigments and

6 ratio of aggregates in asphalt, concrete, and other block pavers can increase their reflectance by up to 30% (EPA 2015).

Numerous studies have identified urban heat mitigation and thermal comfort enhancement of city dwellers by introduction of green infrastructure as an effective measure. (Chui et al. 2018; Saaroni et al. 2018; Zhang, Wu & Chen 2010). Cool building materials refer to any building materials that reduce the temperature of the surface and its surrounding. Cool building materials that exist for roofs are highly reflective roof materials. They have been shown to decrease indoor temperature by 1.2 ℃ to 4.7 ℃ compared to conventional roof materials (Santamouris, Synnefa & Karlessi 2011). Also, conventional paving can be replaced with cooler options (Figure 1.4). Products with light colour, but more importantly high permeability help reducing surface temperatures, whereby emitting less heat into the surrounding environment. In addition, evaporation of stored soil moisture further cools these materials.

Figure 1.4: Examples of different pervious surface materials.

Green infrastructure provides resilience against climate extremes and supports urban liveability through shading, evaporative cooling, and the alteration of wind patterns (Oke et al. 1989). Green infrastructure can be found in different arrangements as parks, street trees, green roofs, and green walls and are the most effective approaches in mitigating increasing urban air temperatures. Especially planting large canopy trees on or around man-made structures can deliver large thermal benefits (Akbari, Pomerantz & Taha 2001). However, expanding green infrastructure in cities is challenging due to competition with development for limited space and other limited resources. Existing land use, increasing urban densification, limited government funding, and shortages in water and council personnel represent some important barriers for the expansion of urban tree canopy in build-up space. In this situation, it becomes paramount to identify alternative spaces to cool urban fabric.

WSUD approaches are taken as a vital part of developing water sensitive cities as they are considered as the most effective approaches in mitigating increasing urban heat (Jamei & Tapper 2019; Sharma, Gardner & Begbie 2018). The key concept behind WSUD is to deliver the prospect to hold the water in cities, particularly during drought and extreme heat conditions along with minimizing the dependence on centralized water supply systems. These benefits are achieved by WSUD through techniques such as “reusing, retaining, treating, and diverting stormwater, by means of technologies such as rainwater tanks, rain gardens, stormwater harvesting systems, and biofiltration systems” (sensu Wong & Brown 2009). The other objective of WSUD is maximising the use of artificial water bodies (e.g., man-made wetlands and lakes). The study by Saaroni and Ziv (2003) reported a negative advection and associated reduction in midday air temperature of 1.6℃ as natural water bodies provide a downwind cooling benefit generated by evaporation and transfer of latent heat from the waterbody. Thus, incorporating WSUD in urban design and especially the design of new urban developments, represents a critical design tool that can help reduce the effect of heat and UHIE on urban populations.

1.2 Heat in Western Sydney

Australia’s climate has warmed since 1910, with an increment of mean surface temperature across Australia by 1 ℃, with an accelerating trend in recent decades. Thus, the duration, frequency, and intensity of heatwaves have amplified across large parts of Australia (Bureau of Meteorology 2018). There has been a continuous increment of mean, daily minimum, and daily maximum temperatures throughout this century for all regions in Australia. In recent decades deviation in warm months has happened more often than the deviation in cold months. Many heat related records were broken in the past 15 years, including the 11 hottest years and hottest day ever recorded in Greater Sydney, where air temperatures soared to 48.7 °C on 4 January 2020. The increase in frequency and severity of heatwaves has killed more people than any other natural disaster in Australia. This will be impacting the population of Greater Sydney that is expected to grow by 1.6 million until 2036 (Greater Sydney Commission 2016). Heat stress already has a severe impact on the quality of life in Australian cities and it is the foremost natural disruptor in Greater Sydney (Resilient Sydney 2018; WSROC 2018). Therefore, it can be expected that increasing urbanization will worsen the effects of climate change by further accelerating local warming and associated UHIE (Coutts et al. 2016; Levermore et al. 2018).

Sydney has a warm-temperate climate and is characterised by warm summer and cold winters (Beck et al. 2018). The climate of Greater Sydney is significantly affected by its coastal site and the nearness to the ocean. This can be observed by the upsurge in mean summer temperatures from the coastal zone near the central business district (CBD) of the City of Sydney towards the west, where air temperatures are usually 2–5 °C warmer. This, however, depends on the wind speed and direction (Santamouris et al. 2017). Western Sydney is particularly exposed, as, unlike the coastal suburbs, it does not receive the moderating influence of a cooling sea breeze. Indeed, analyses of available temperature records for the Sydney Basin found that western Sydney is heating up more quickly compared to the City of Sydney.

For some time now, Greater Western Sydney has experienced a phase of intense transformation, where former pastoral and agricultural land is transformed into residential housing, roads, and other hard infrastructure (Smith 2003). Until 2036, it is anticipated that another 800,000 residents will call western Sydney their home (Greater Sydney Commission 2018). This large-scale conversion of green to grey infrastructure in Sydney’s west has been predicted to worsen already severe summer heat impacts (Reeves et al. 2010). During the past 40 years, western Sydney weather stations have recorded a rise in annual temperatures above the predicted temperature through global warming (Bureau of Meteorology 2018). During heatwaves, western Sydney is subjected to 6-10 °C higher temperatures compared to the eastern suburbs (CSIRO & Meteorology 2015). Meteorological data also shows that the days over 35 ℃ have increased from an historical average of 1 day per year in the late 1960’s, to more than 15 days per year in late the 2010’s in western Sydney. Similar, the annual number of days with air temperatures greater than 40 °C has also increased. These extreme heat events have a key impact on productivity and economic activity long with adverse effects on health and safety of workers (Ogge, Browne & Hughes 2018) and vulnerable groups of the local population, such as children and the elderly. Hence, it becomes especially important to identify effective Fstrategies that help reduce heat across the region.

1.3 Car Dependency

The heavy reliance of citizens on private cars for transport as a result of the design and location of new settlements across urban Australia has long been known (Hensher 1998). On a global scale, dependence on cars is greatest in cities of the United States, followed by cities in Canada and Australia, and is much lower in European and Asian cities (Kenworthy & Laube 1999). A 9 range of factors determines how car dependent a city is. They are usually related to cost difference between public transport and car use and public transport operating costs (Tong & Wong 1997), accessibility of public transport, the time and distance to work, and the type of urban form (Marchetti 1994). Also, the cost of owning and operating a car can influence dependence (Giuliano & Dargay 2006; Kenworthy & Laube 1999). According to urban economic theory, the vehicle of choice and distance travelled by an average household depends on the size of the city, the dispersal of employment, and the public transport and road network (Bento, Cropper & Mobarak 2005).

The decision to use private or public means of transport has been shown to also depend on parking availability at the destination and home (Christiansen 2014). In cities with high car dependency, industrial estates, shopping malls, hospitals, central business districts and other businesses providing work, goods, and services for the citizens must offer sufficient parking space. Parking accessibility and its cost at the destination have a great influence on travel behaviour, including choice of travel mode, choice of destination, and even car ownership and occupancy (Feeney 1989; Guo 2013; Inci 2015). Evidence shows that car use is the lowest in large densely built urban areas, areas close to city centres and areas in which a high number of people work and have sufficient access to public transport services (Christiansen et al. 2017; Næss 2012; Newman & Kenworthy 1989).

The Car parking facilities have become an essential constituent of entire urban developments. Inadequate provision of carparks can lead to congestion, unsafe traffic conditions, or result in illegal parking therefore have an adverse effect on commercial viability of businesses. On the other hand, an excessive provision of car parking spaces may boost car use and also uneconomical use of urban land.

1.4 Carparks as Sources of Urban Heat

Car parking is a main land use identified to occupy in some cases over 30% of the ground area of some cities (Ben-Joseph 2012; LOCI 2017). Conventional, flat, open, asphalt-covered carparks can be found in cities around the world. These types of carparks are a known source for urban heat (Shoup 2018), representing small localized islands, or more accurately, islets of urban heat. These impervious surfaces are often constructed by replacing the natural vegetation cover. Hence, it increases the runoff and also offers a place for traffic-generated residues and 10 pollutants to wash off (Rushton 2001). Moreover, carparks have been linked to the presence of air pollution in the lower atmosphere especially during the daytime where they can be directly proportional to the occupancy of a carparking area (Gentili et al. 2019). Parking has always been a topic of debate and has great significance to both regional and local strategic urban planning. Ironically, complaints for insufficient parking facility appears to raise in direct proportion to the quantity of parking supplied (Young, Thompson & Taylor 1991). Several factors play important roles in prompting demand for parking, which can be broadly classified as the socioeconomic and psychological characteristics of drivers, features of the parking facility, and alternative transportation. Moreover, in-vehicle costs like fuel cost, travel time are less influential to car users than out-vehicle costs that includes of parking charges, driving and walking time (Parmar, Das & Dave 2020).

Many carparks are rarely at their full capacity, and quite often even empty (LOCI 2017). Numerous attempts have been made to reform car parking policies and procedures, including reducing or removing minimum off-street parking requirements, and changes in providing free or under-priced curb side parking (Shoup 2018). New, innovative planning and design strategies are necessary to build heat resilient carparks and identify the potential to convert existing conventional carparks into cool carparks. Studies estimating the potential for mitigation of UHIE have shown that greening parking lots can have a cooling effect by decreasing surface heat budgets (Onishi et al. 2010; Takebayashi & Moriyama 2009). Once other means of transport have been provided, cities can convert obsolete parking areas to recreational areas and public squares (Garrick & McCahill 2012). Good examples for such conversions are West End Square in Dallas, United States or Prahran Square in Melbourne, Australia.

Other design interventions to reduce heat in carparks can be used. These include reflective coatings that contain infrared-reflective pigments along with a new generation of permeable materials (Santamouris 2013). More permanent structures can also be used to provide shade, including sails or solar canopies. Solar canopies are raised structures that offer shade as well as host solar panels (Nunes, Figueiredo & Brito 2016). They shield paved or other hard surfaces that otherwise absorb a large proportion of the sun’s energy (Turan et al. 2019), which as described above will warm local air temperature and intensifies UHIE. Solar structures can be a beneficial addition to any carparking, as they provide numerous benefits. Carparks with solar roofs can provide clean and regenerative energy to power buildings and electric cars. The 11 elevated shade structures also known as carports protect cars from sun and hail damage and will keep the interior of cars cooler in summer. A cooler car would also require less energy to be cooled down at the beginning of a trip, whereby the engine would produce less carbon dioxide emissions (Energy 2019).

In conclusion, current green-field development in western Sydney includes the construction of new conventional carparks, which all contribute to increasing urban heat. To date, the establishment of carparks is a fundamental component of urban development in western Sydney. The provision of insufficient carparking space or limited access to public transport systems can lead to congested traffic conditions. However, a sound understanding of the impacts of carparks on microclimates and UHIE is lacking. It is currently unknown how much urban space is covered by carparks in Greater Western Sydney, and if this space is increasing proportionally with the growing population.

1.5 Thesis Overview

Residents of Greater Western Sydney frequently experience UHIE and extreme heat in summer, leaving urban areas hotter compared to nearby rural land. This phenomenon is linked to the large proportion of hard surfaces from commercial and residential buildings, roads, and parking lots that dominate urban space. Especially the dark, flat surfaces of car parks store and re-radiate large amounts of solar energy and contribute to local heat. This project aims at quantifying the area of car park infrastructure across six local government areas in western Sydney. It will also investigate how the area used for car parks has changed between 2010 and 2019 and will assess features and characteristics of car parks such as tree shade and building materials. Carparks are omnipresent, unnoticed, yet necessary and unavoidable. Importantly, they are notorious contributors to the UHIE. Predicted trends in extreme summer temperatures paired with rapid urbanization across Greater Western Sydney create a situation where a fundamental rethinking of carpark design is urgently needed. However, physical evidence that can inform optimised thermal design of carparks is currently missing.

This project will improve our understanding of the extent to which growing populations lead to more carparking spaces. The results of this study will demonstrate how the area used by car parks is increasing in western Sydney. This is critical information for urban planners, landscape

12 designers, and policymakers who want to increase the resilience of existing and new settlements in western Sydney against heat.

Aims and Objectives The main aim of this project is to determine the area covered by carparks across more and less densely populated local government areas in western Sydney. Further, it will shed light on the relationship between population growth and space covered by conventional carparks. Through a set of physical measurements, it will provide empirical evidence for the capacity of shade to reduce surface temperatures in carparks. Lastly, it will assess the existing extent of tree canopy cover in carparks. Thus, this project aims to answer the following policy and planning questions:

1. How much land surface in local government areas of western Sydney is covered by carparks?

2. Which council of the western Sydney Basin has the greatest and the least increase in new conventional carpark space?

3. Does this observation match with the recent population increase in these local government areas?

4. How much green infrastructure (e.g. trees, shrubs) is present in carparks that can mitigate summer heat and reduce UHI effects?

2 Materials and Methods

2.1 Study Areas

Greater Western Sydney (GWS) is a region that spans from Parramatta in the east to Penrith in the west, Windsor in the north, and Campbelltown in the south of the Sydney Basin in New South Wales, Australia. The region houses Australia’s third-largest economy, superseded only by economic growth generated in the CBD of Sydney and Melbourne. Currently, GWS experiences the fastest growth rates in population, jobs, and gross primary productivity in Australia. The New South Wales Department of Planning's Metropolitan Strategy divides Greater Western Sydney into three sub-regions (i.e. West Central, South West, and West) that contain 13 local government areas (LGAs).

Six of the 13 LGAs (Figure 2.1) were studied for the current project. The selection of the six LGAs was guided by a preliminary assessment of available landforms (ranging from highly urban to rural), population density, centres of ongoing conversion of green to grey infrastructure, and geographical location. The following LGAs were selected:

1. Parramatta – West Central sub-region, a mix of low-, medium- and high-density housing, no rural land, CBD of the Central River City. 2. Cumberland – West Central sub-region, a mix of low- and medium-density housing, no rural land. 3. Blacktown – West Central sub-region, a mix of low- and medium-density housing, a large proportion of rural land, high rates of conversion from green to grey infrastructure. 4. Penrith – West sub-region, predominately low-density housing, a large proportion of rural land, medium rates of conversion from green to grey infrastructure. 5. Camden – South West sub-region, predominately low-density housing, a large proportion of rural land, high rates of conversion from green to grey infrastructure. 6. Campbelltown – South West sub-region, a mix of low- and medium-density housing, some rural land, high rates of conversion from green to grey infrastructure.

Figure 2.1: Map of western Sydney with the six studied local government areas marked with red lines.

To assess the increase in carpark space in each suburb of each LGA, the current project used high-resolution aerial images from April 2010 and June 2019 (Figure 2.2). Large-scale conversion of rural to urban land is occurring in all LGAs, except Parramatta and Cumberland where densification, rather than the conversion of land dominates efforts to meet the increasing demand for housing. As a result, large areas of green pervious land are converted to carparks (Figure 2.2).

(a) (b)

Figure 2.2: Image showing an area of Marsden Park, LGA of Blacktown. Panel (a) depicts a rural landscape in 2010 that by 2019, shown in panel (b) has been completely converted to a large green field development with shops and extensive asphalt carparks. Images were taken from Nearmap.

2.2 Carpark Assessments

For this study, carparks were defined as open, flat areas exposed to solar radiation. The areas could have been covered by any surface material and were permanently used for parking of cars. Application of these selection criteria resulted in excluding underground parking lots and accounting only for the top parking story of multi-level carparks. Further, permanent carparks with less than 10 parking spaces were also excluded, as it was assumed that heat radiated from these small carparks would not have made a significant contribution to local microclimates.

Carpark infrastructure in each of the selected LGAs was identified manually using high resolution aerial photographs provided by Nearmap (Nearmap, Barangaroo, Australia). Geographical position and the physical address of each carpark was recorded using the location function in Google Maps (Google LLC, Menlo Park, United States). A range of characteristics of each carpark was determined using visual assessment and spatial analysis tools provided in Nearmap (e.g. polygon function) (Figure 2.3). Where necessary, characteristics of carparks (listed in Table 2.1) were further investigated using the street view function in Google Maps. In total, this project analysed 2,250 carparks in the six LGAs, of which 409 were classified as ‘small’, and 1,841 as ‘large’.

(a) (b)

Figure 2.3: Measuring area of car park and tree crown area of Western Sydney University Paramatta South.

Table 2.1: Key categories, attributes, and units assessed for each carpark. Categories Attributes Unit Location N/A °latitude, °longitude Total parking area N/A ha Type of shade Trees, sails, hard roof, solar N/A Number of shade structures N Total shaded area Ha Total green area Ha Surface material Concrete/asphalt/gravel, grass, N/A uncovered soil Types of carpark Multistorey/ Street/Single layered N/A

The category ‘green area’ in Table 2.1 included the area of a carpark covered by green plants of low statue (herbs, short shrubs, and grasses). This category also included very small trees that did not provide a measurable area of shade in 2010 or 2019 (typically tree canopies <1 m2). If a measurable proportion of shaded area was present, its spatial extent and source were determined, using the attributes listed in Table 2.1. An example for a bare conventional carpark and one with noticeable green infrastructure is provided for each LGA in the following two figures (Figs. 2.4 and 2.5)

(a) (b)

(e) (f)

Figure 2.4: Examples of conventional carparks with little or no green infrastructure in 2019. Examples are provided for (a) Blacktown: 17 Patrick St, (b) Campbelltown: 9 Redfern Rd, (c) Camden: 2A Porrende St, (d) Cumberland: 15 Mack St, (e) Parramatta: 9 Hill Rd and (f) Penrith. Image: 72 Mulgoa Rd. Image source: Nearmap.

(a) (b)

(e) (f)

Figure 2.5: Examples of conventional carparks with noticeable proportions of green infrastructure, especially tree canopy, in 2019. Examples are provided for (a) Blacktown: Sentry Dr, (b) Campbelltown: 281 Queen St, (c) Camden: Sydney Assembly Hall (d) Cumberland: 615A Great Western Hwy, (e) Parramatta: Shane Gould Ave and (f) Penrith: 56 Second Ave, Kingswood. Image source: Nearmap.

For the categorisation of carparks according to their size, it was necessary to define a threshold area for small and large carparks. As no official definition of small and large carparks exist in the literature, this study adopted the concept that small carparks are those that provide parking bays for 50 or fewer cars. The threshold area of such carparks was determined by selecting 20 carparks at random. Within each of these carparks five delineated parking spaces were measured using the polygon function in Nearmap, generating spatial data for 100 carparking spaces. The average of these spaces was multiplied by 50 and an additional 10% of space was added to include areas that represent driveway and road infrastructure necessary to move vehicles in and out of carparks. This calculation resulted in a threshold area for small carparks to be 682 m2 or less.

2.3 Demographic Data

Population data was sourced through the online platform of profile.id. This platform uses Census data, from the last 20 years to build a powerful story about the characteristics of a community, how it has changed, and how it is expected to look like in the future. Census data in Australia is collected at 5-year intervals in years ending -1 and -6. For intermediate years, the Australian Bureau of Statistics provides annual estimates of changes in population. However, at the suburb-level for the LGAs investigated here, the closest match for the dates of aerial imagery from 2010 and 2019 was 2012 and 2018. Admittedly, this was not ideal, yet it represented the best possible scenario for matching the presence and spatial extent of carparks with the dynamic change of local populations. Population.id also provides information about the area covered by individual suburbs. This information was also recorded to estimate the relative area of carparking space as proportion of the total size of each suburb.

2.4 Carpark Heat

Environmental data were collected at four conventional, black asphalt carparks at:

1. Parramatta South Campus of Western Sydney University Victoria Road, Parramatta NSW 2150, Lat/Long -33°48'34", 151°1'37" 2. Parramatta stadium park Pitt St &, Macquarie St, Parramatta NSW 2150, Lat/Long-33°48'25", 151°0'1"

3. Granville railway station and 1C Memorial Dr, Granville NSW 2142, Lat/Long -33°50'1", 151°0'45" 4. Granville library. 8 Carlton St, Granville NSW 2142, Lat/Long -33°49'57",151°0'33"

Surface temperatures of carparks were assessed using a high-resolution infrared camera (T540, FLIR Systems, Wilsonville, United States). Images were taken in both shaded and unshaded areas of each carpark during midday on 4 days with clear sky. Surface temperatures at each carpark were recorded on two individual days.

Parramatta South Campus of WSU 2/03/2020 13/03/2020 Parramatta stadium park 18/03/2020 19/03/2020 Granville railway station 13/03/2020 18/03/2020 Granville library 13/03/2020 18/03/2020

In each of the images, the emissivity was set to 0.95 as instructed in the FLIR guidebook (asphalt = 0.93-0.95) and the temperature indicator was set to 25 to 50 ℃.

Micrometeorological data were collected in parallel to infrared imaging. Air and black globe temperature were recorded using a portable weather station (Kestrel 5400, Boothwyn, United States). The black globe thermometer represents an integrated ‘feels like’ temperature that combines incoming solar radiation, radiated surface heat, air temperature and wind speed. At each carpark and shaded and sunlit positions, data were recorded at 30 second intervals for at least 15 minutes. During calculation final 5 min data were only taken as to allow the instrument to equilibrate to the ambient conditions, ensuring that only apparent ambient conditions were recorded and analysed.

2.5 Statistical Analysis

Pearson’s correlations were used to analyse the relationships between population change and change in carpark area, as well as a change in green space. Pearson’s correlation (r) measures a linear dependence between two variables. However, correlation does not imply causation, 21 and if a significant correlation was found, the association was tested with linear regression. The significance level was set at p<0.05 for all analyses. Linear regression analysis was used to assess whether the change in carparking area and change in population or the ratio of total carpark area to suburb area (all independent variables) were related. The goodness of fit was given as R2. Analysis of Variance (ANOVA) was used to test the differences between two sample populations. It was done for demographic data including a population of LGA “2010” to “2019” and carpark assessment data including carpark area of “2010” to “2019” along with green space, number of trees, and tree shade area. The thermal images (shaded and unshaded region) of each site were used to extract 10 random measurements of surface temperature to calculate means and their standard deviation. Only micrometeorological data recorded during the last 5 minutes at each location and carpark were used to calculate the mean (and 1 standard deviation) air and black globe temperature. Data from both measurement days were averaged for each location and carpark.

3 Results

3.1 Overview

3.1.1 Demographic Status Data about the demographic status of the study areas identified Blacktown as the most populated LGA (population in 2018: 317,735) and Camden as the least populated LGA (population in 2018: 61,127) (Table 3.1). In terms of size, Penrith covered the largest area (405 km2) and Cumberland the smallest (71.67 km2). While large differences existed in populations and land areas, also the change in the population varied markedly among the six LGAs. While the population of Campbelltown City increased by just 9.52% between 2012 and 2018, the population of Camden grew by 54% at the same time (Table 3.1).

Table 3.1: Demographic status and size of six local government areas (LGAs) in western Sydney.

Population Population Population Area (km2) (2012) (2018) change (%) Blacktown 317,735 366,078 15.2 240.13 Campbelltown 152,425 166,930 9.5 311.33 Camden 61,127 94,029 53.8 200.96 Cumberland 207,528 236,599 14.0 71.67 Parramatta 208,182 251,065 20.6 83.75 Penrith 187,281 208,947 11.6 404.77

3.1.2 Carpark Types Most of the studied carparks (about 95%) were conventional surface carparks, separated from roads by access lanes or ramps. Because carparks with less than 10 parking bays were excluded in this analysis, the least common carpark type was street parking. Multistorey carparks represented 4% of all carparking spaces analysed (Figure 3.1), although their number notably varied among the six LGAs. Camden as a more rural LGA had the fewest (5% of all carparks), whereas the highly urbanised LGAs of Parramatta and Cumberland had the highest number of multistorey car parks (35% and 23% of all carparks) (Figure 3.1).

Penrith 9% Blacktown 16% Conventional 95% Multistorey Campbeltown 4% 12% Parramatta Camden 35% Street 5% 1% Cumberland 23%

Figure 3.1: Relative proportion of different types of carparks analysed in the present study. Multistorey carparks are listed separately for each of the six investigated LGAs.

Carparks surfaces were predominately one of three types: asphalt, concrete or gravel. The vast majority of carpark surfaces was made from conventional black asphalt (Figure 3.2). Less than 10% of carpark surfaces were made from lighter-coloured concrete in five of the six LGAs. Only in Camden did the proportion of carparks that were made from concrete reach 18%. Only three carparks in the LGA of Penrith were surfaced using gravel or blue metal rock (Figure 3.2).

(a) (b) (c)

(d) (e) (f)

Figure 3.2: Surface materials used in carparks of the six western Sydney LGAs. Dark grey: black asphalt, light grey: concrete, very light grey: gravel (Penrith only). 24

3.1.3 Carpark Area Among all six LGAs, the total number of carparks increased from 1881 in 2010 to 2188 in 2020 (Table 3.2). At the same time, 116 carparks that were present in 2010 had disappeared in 2019. This dynamic change represents a net increase in the number of carparks by 16 %. The area covered by carparks had increased by 22 %, or from 489 ha to 595 ha. The largest increase in carparking space was observed in Camden (+89%), growing from 148 sites in 2010 to 218 sites in 2019. In comparison, the area covered by carparks increased by a mere 8 % in Campbelltown, where 247 carparks in 2010 grew to 270 in 2019.

Table 3.2: Overview of the number and size of carparks across all suburbs of the investigated LGAs in western Sydney for the years of 2010 and 2019. LGA 2010 2019

No. of carparks Total carpark area (ha) No. of carparks Total carpark area (ha) Blacktown 452 112.65 596 159.53 Campbelltown 251 82.63 275 89.28 Camden 148 26.12 218 49.22 Cumberland 288 83.36 311 92.38 Parramatta 458 106.64 449 115.44 Penrith 284 77.75 339 89.99

Among six different LGAs, calculating the average contribution of carparking space to individual suburbs across LGAs for 2010 and 2019 (Table 3.3) revealed that while the average suburb area remained constant, the relative amount of space taken up by carparks varied significantly within and among LGAs. The densely populated LGAs of Parramatta and Cumberland had the largest proportion of carpark area covering their suburbs, where they took up on average more than 100 m2 ha-1 in 2010 and 2019 across their suburbs (Table 3.3). Notably, the relative coverage of carparks increased in all six LGAs, with the largest increase across suburbs of Camden (+53%) and the least increase in suburbs of Campbelltown (+8%) and Cumberland (+7%).

Table 3.3: Variation in the ratio of carpark space relative to suburb size among the six LGAs between 2010 and 2019.

LGA Mean area of carparks Mean area of carparks Relative change in the area across suburbs in 2010 across suburbs in 2019 of carparks across suburbs (m2 ha-1) (m2 ha-1) between 2010 and 2019 (%) Blacktown 52.5 63.33 +20.63 Campbelltown 49 52.77 +7.68 Camden 32.24 49.19 +52.55 Cumberland 101.86 109.44 +7.43 Parramatta 142.2 158.46 +11.42 Penrith 41.18 47.53 +15.41

When looking at individual suburbs within LGAs, only Cumberland had no suburbs free of carparks in 2010 and 2019, while Camden had two suburbs free of carparks in 2010 (Leppington, Oran Park), but none in 2019. In Parramatta, five suburbs remained free of carparks in 2010 and 2019 (Beecroft, Dundas Valley, North Parramatta, Oatlands, Telopea) and there were five suburbs that had not carparks in 2010 and 2019 in Campbelltown (Blair Athol, Blairmount, Claymore, Macquarie Links, Rural Residential). In Penrith, the number of carpark free suburbs declined from 11 in 2010 (Berkshire Park, Castlereagh/Agnes Banks, Emu Heights, Emu Plains, Leonay, Londonderry, Luddenham – Wallacia, North St Marys, Regentville, Werrington Downs, Jordan Springs) to 10 in 2019 as Jordan Springs was developed. The largest decline in carpark free suburbs, however, was observed for Blacktown, where in 2010 seven suburbs were carpark free (Blackett, Bungarribee, Colebee, Dean Park, Riverstone, Whalan, Willmot). By 2019, urban development had resulted in carpark constructions in Bungarribee, Colebee, and Riverstone, leaving only four suburbs free of carparks with more than 10 parking spaces.

In 2019, the suburbs with the largest ratio of carparking space to suburb area were Emerson in Blacktown (293 m2 ha-1), Gledswood/Gregory Hills in Camden (157 m2 ha-1), Campbelltown CBD (358 m2 ha-1), Pemulwuy/Prospect in Cumberland (258 m2 ha-1), Westmead in Parramatta (1073 m2 ha-1) and Jamisontown in Penrith (320 m2 ha-1).

The relationship between population size and the area covered by carparks was highly significant for the earlier (population of 2012, carparking area of 2010) and more recent (population of 2018, carparking area of 2019) timepoints (Fig 3.3). Notably, the positive relationship changed from a curvilinear relation at the earlier timepoint to a strongly linear

26 relationship, which is predominately driven by the over proportional increase in carpark area across the LGA of Blacktown.

Figure 3.3: Relationship between the population of the six investigated LGAs and the area covered by carparks. Panel a shows the early timepoint (population of 2012, carpark area of 2010), while panel b shows the more recent timepoint (population of 2018, carpark area of 2019) assessed in this study.

3.1.4 Green Infrastructure The area covered by green infrastructure in carparks across the investigated western Sydney councils was very low. In 2010, 3880 trees and other green infrastructure covered only 1% of the total carpark area. This coverage remained unchanged in 2019, where 4471 trees were counted. It should be noted that the net area covered by green infrastructure in carparks did increase in only four of the six councils (Table 3.4).

Table 3.4: Total area of green infrastructure, number of trees and the ground area shaded by trees in carparks of six western Sydney LGAs for 2010 and 2019.

LGA 2010 2019 Green No. of Tree shade Green No. of Tree shade area (ha) trees area (ha) area (ha) trees area (ha) Blacktown 0.50 1067 1.69 0.98 1406 1.84 Campbelltown 0.29 722 0.73 0.27 721 1.03 Camden 1.06 116 0.61 1.67 215 0.75 Cumberland 0.46 730 0.81 0.42 795 0.99 Parramatta 1.10 742 1.79 1.22 780 1.92 Penrith 1.37 553 1.56 1.69 607 1.61

Trees varied in canopy size and number (Table 3.5). In 2019 more than 60 % of carparks were without any trees. The number of trees in carparks varied from 1-85 and the area covered by individual tree canopies ranged from 8 m2 to 15 m2. One carpark in Parramatta had the highest tree canopy cover where crowns covered an area of 2500 m2.

Table 3.5: Status of trees (number and area) in 2019 for each of the six studied LGAs. Number Area (m2) Car park Ratio to total Mean Min Max Mean Min Max with tree carpark Blacktown 149 33% 9.2 1 65 170 15 1800 Campbelltown 77 31% 9.4 1 50 94.4 15 700 Camden 35 24% 7.5 1 80 197.9 20 600 Cumberland 100 41% 8.2 1 85 77.5 8 620 Parramatta 88 19% 9.1 1 80 223.8 15 2500 Penrith 94 33% 6.5 1 26 172.1 10 1500

The area covered by green vegetation was positively related to the area of carparking space across all LGAs and their suburbs included in the study (Figure 3.4). Although this relationship was relatively weak, it was statistically significant (p <0.05). Much stronger and highly significant (p <0.01) was the relationship between the number of trees and the parking area these trees shaded when the total area of carparks in individual suburbs increased. These strong relationships indicated that the trend towards greener carparks increased with the amount of space dedicated to carparks, regardless of geographical location of the suburb and LGA.

Figure 3.4 (previous page): Relationship between the total area of carparks in suburbs of the six LGAs in western Sydney and green area (panels a and d), number of trees (panels b and e) and the area shaded by trees (panels c and f). Top panels show data for 2010, bottom panels show data for 2019. All relationships were statistically significant, with p<0.05. Red, dotted lines depict linear trends and coefficients of determination are shown for each trend.

3.1.5 Population and Carpark Dynamics Analyses of data from 143 suburbs indicated that an increase in population resulted in a highly significant increase in the area covered by carparks (p <0.001). Although individual suburbs existed where an increase of population led to a decline in carparking space (e.g. Parramatta CBD, Eastwood, Ermington – Melrose Park), the general trend was that 4000 new residents resulted in an addition of two hectares carparking space (Figure 3.5a).

With the increase in carparking area, a parallel and highly significant increase in area covered by green infrastructure (p <0.001; Figure 3.5b) and the number of trees planted in carparks (p<0.001; Figure 3.5c) occurred. Yet the total areas of additional green infrastructure and numbers of additional trees were rather small. The number of trees growing in carparks remained unchanged in the majority of suburbs (n = 92) and declined in more than 10% of all suburbs (n = 16), with the largest tree losses in Sydney Olympic Park (-25 trees), Lidcombe/Rookwood (-29 trees) and Blacktown CBD (-39 trees). The largest increases in the number of trees were observed at Pemulwuy/Prospect (+88 trees), Glenwood (+85 trees) and Gledswood/Gregory Hills (+80 trees). A weak, though statistically significant and positive relationship was detected between the increase in the number of trees and the area of shade provided (p<0.0001; Figure 3.5d).

(a) (b)0.35 14 y = 0.0099x + 0.005 y = 0.0005x + 0.16 R² = 0.27 R² = 0.17 0.25 10

6 0.15

0.05

Change in in (ha) area Change parking Change in green area (ha) area in Change green

-2 -1000 1000 3000 5000 7000 9000 -0.05 Change in population (N) -2 2 6 10 14 Change in Parking area (ha) (c)110 (d) 0.3 y = 4.5962x + 1.37 R² = 0.23 y = 0.0007x + 0.007 80 0.2 R² = 0.11

50 0.1

20 0 Change in in trees Change (N) of no

-10 (ha) in Change shade tree -0.1

-40 -0.2 -2 2 6 10 14 -40 -10 20 50 80 110 Change in parking area (ha) Change in no of trees (N) Figure 3.5: Dynamics of population and carpark attributes based on observed changes between 2010/2012 and 2018/2019 across 143 suburbs in six western Sydney councils. (a) Relationship of changes in local populations with changes in the area covered by carparks. (b) Relationship between the change in the area covered by carparks and the change in the area covered by green infrastructure. (c) Relationship between change in area covered by carparks and the change in the number of trees growing inside the carparks. d) Relationship between the change in the number of trees and the change in the area of shade provided by these trees. Linear regressions as well as 95% confidence intervals are shown.

3.2 Heat in Carparks

The black globe temperature represents a measurement that integrates a range of factors that contribute to how a body (the black sphere) is experiencing temperature of the surrounding environment. Due to its sensitivity to solar radiation and surface heat emission it showed a larger temperature difference between sunlit and shaded carpark areas when compared with air temperature. The difference in mean air temperature measured in the sun and in shade on four carparks was 0.8℃ to 2.6℃ (Figure 3.6). Compared to the modest cooling effect of shade on ambient air temperature, the effect of shade on black globe temperature was with 6.3℃ to 9.4℃ far greater (Fig 3.6).

Figure 3.6: Mean air temperature (panel a) and mean black globe temperature (panel b) of four conventional asphalt carparks in western Sydney. Measurements were collected during sunny days at locations in full sun and in the shade of trees. For each mean n = 10. Error bars show 1 standard deviation of the mean.

Surface temperatures of black asphalt in direct sunlight was up to 53 °C. Averaged across all measurement days and locations, sunlit asphalt was around 46 °C (Figure 3.7). The highest surface temperatures were measured on the carpark at Parramatta park, leading also to the highest black globe temperatures due to radiant heat from the surface. Notably, measurements at Parramatta park were not collected during the hottest day – as indicated by lower mean air temperatures at Parramatta park compared to those measured at the carpark of Western Sydney University.

Shading black asphalt greatly reduced surface temperatures (Figure 3.7), much more so than the effect of shade on black globe or air temperatures. Shade reduced the surface temperature 31 at Parramatta park by as much as 25°C and about 16 °C at Granville station. The lowest surface cooling by shade was observed at the carpark of Western Sydney University where temperatures were 8 °C cooler on shaded compared to sunlit asphalt.

50 ℃) 45

Surface temperature Surfacetemperature ( 25

20 WSU P' South Parramatta Granville Granville park station library

Figure 3.7: Mean surface temperatures of four conventional asphalt carparks in western Sydney. Measurements were collected during sunny days at locations in full sun and in the shade of trees. For each mean n = 10. Error bars show 1 standard deviation of the mean.

The images produced with the infrared camera (Figure 3.8) show variation of surface temperatures of up to 20 °C according to light conditions. All images were scaled to show the same colour gradients for surface temperatures between 25 and 50 °C.

(a) (b)

(e) (f)

Figure 3.8: Examples for the effect of direct sunshine and shade on surface temperatures of black asphalt carparks in western Sydney. Left panels show actual view, right panels show infrared view. Panels a and b: unshaded section of the carpark at Western Sydney University carpark. Panels c and d: partly shaded carpark at Parramatta park. Panels e and f: shaded section of the carpark at the Granville library. The tripod-mounted micrometeorological weather station for measurements of air and black globe temperatures is visible in all images.

3.3 Individual Councils

3.3.1 Blacktown The LGA of Blacktown City is located in Sydney's west, about 35 kilometers from the Sydney CBD. In 2012, 317,735 people lived in the LGA of Blacktown City, which covered an area of 366,08 hectares, across 39 suburbs (see Figure S1 at the end of this thesis). By 2018, the population had increased to 366,379, leading to a highly significant increase in population (p <0.001). Population density rose from 13.2 people per hectare in 2010 to 15.3 people per hectare in 2018.

Figure 3.9: Location of carparks across the LGA of Blacktown. The boundary of the LGA is depicted as a blue line. The red dots show the locations of carparks across the LGA. The insert in the top left shows the location of the LGA (marked in yellow) in the larger context of the Sydney Basin. While the population of Blacktown City generally increased, this trend did not apply to every suburb. The average relative population increase between 2012 and 2018 was 125.81%. The highest population increase in a single suburb was in Bungarribee where 85 residents were recorded in 2012 and 2,993 in 2018, a change of +3,421%. Between 2012 and 2018, the population in all suburbs increased with two exceptions. The population of Bidwill declined by 8% and that of Emerton by 6% (Table 3.6).

Across the LGA, 596 carparks were identified and analysed for the timepoints of 2010 and 2019 (Table 3.6). 102 of these carparks were classified as ‘small’. The concentration of carparks was greater in the eastern and southern parts of the LGA (see Figure 3.9). However, clusters of new carparks were identifiable in the north-western section where significant development has taken place.

The total area covered by car parks increased from 452 ha in 2010 to 596 ha in 2019, representing an addition of 144 ha, or 26%. The average area covered by carparks across the 39 suburbs of Blacktown City was 66 m2 ha-1. Emerton had the largest proportion of carparks, covering 293 m2 ha-1. The overall largest increase in carpark area between 2010 and 2019 was observed for Marsden Park/Shanes Park where the number of carparks changed from 1 to 30, the area covered from 0.3 to 14.6 hectare, increasing the ratio of carparking area to suburb area from 1 m2 ha-1 to 39 m2 ha-1. Between 2010 and 2019, the area covered by carparks remained unchanged in 21 of the 39 suburbs. The number of carparks ranged from 0 to 65 in the suburbs of Blacktown and was on average around 12 (±2.85) in 2010. The range of carparks changed from 0 to 86 in 2019, and a mean number of carparks of around 15 (±3.42) per suburb.

As mentioned earlier, the number of suburbs in Blacktown that did not have any carparks declined from seven in 2010 to four in 2019. The highest number of carparks in an individual suburb in 2019 was in Rooty Hill, where 86 carparks covered a total area of 21.24 ha, representing an increase of 27% since 2010 (Table 3.6). Although slightly less in number (n = 74), carparks in Blacktown CBD covered the largest area of a single suburb in this LGA (23.5 ha). While the area of carparks across the LGA increased on average by 142% in each suburb, some suburbs experienced nil change in relative parking area (e.g., Kings Park, Minchinbury

35 or Plumpton; Table 3.6), whereas others saw large increases (e.g., Marsden Park: +4123%, The Ponds: 298%; Table 3.6).

Table 3.6: Carparks, population, and their change between 2010 and 2019 across the suburbs of Blacktown City.

2010 2019 Ratio of Relative Parking to Parking Relative No. of Parking No. of Parking Population Population Suburb Suburb area area Change Population Carparks area (ha) Carparks area (ha) (2012) (2018) Area (ha) (m² ha¯¹) (% ) Change (% ) Acacia Gardens- Parklea 1 3.04 2 3.48 6,986 7,691 205 169.7 14.5 10.1 Bidwill 3 1.01 3 1.01 4,689 4,322 151 66.6 0.0 -7.8 Blackett 0 0.00 0 0.00 3,508 3,596 106 0.0 0.0 2.5 Blacktown 65 19.59 74 23.46 45,859 49,700 1,591 147.5 19.8 8.4 Bugarribee 0 0.00 2 0.46 85 2,993 352 13.1 0.0 3421.2 Colebee 0 0.00 4 1.12 304 2,693 351 31.9 0.0 785.9 Dean Park 0 0.00 0 0.00 3,225 3,348 148 0.0 0.0 3.8 Dharruk 4 0.83 4 0.83 2,840 2,853 94 88.7 0.0 0.5 Doonside 9 1.41 10 1.66 13,805 14,707 595 27.8 17.7 6.5 Emerton 9 2.63 9 2.63 2,472 2,313 90 292.6 0.0 -6.4 Glendenning 31 3.55 31 3.55 5,228 5,388 353 100.5 0.0 3.1 Glenwood 19 6.36 24 7.68 16,101 16,905 487 157.7 20.7 5.0 Hassal Grove 4 0.44 4 0.44 4,575 4,739 121 36.7 0.0 3.6 Hebersham 5 0.34 7 1.03 5,675 5,884 168 61.5 207.8 3.7 Kellyville Ridge 2 0.19 3 0.42 8,845 11,013 263 16.1 118.8 24.5 kings Langley 5 0.51 5 0.51 9,598 9,727 391 13.1 0.0 1.3 Kings Park 3 0.93 3 0.93 3,469 3,669 260 35.6 0.0 5.8 Lalor Park 1 0.38 2 0.57 7,455 7,924 266 21.3 47.5 6.3 Lethbridge park 1 0.05 1 0.05 4,857 5,091 164 3.0 0.0 4.8 Marayong 4 0.51 4 0.51 7,682 8,347 271 18.9 0.0 8.7 Marsden Park- Shannes Park 1 0.34 30 14.52 3,280 9,935 3,760 38.6 4123.6 202.9 Minchinbury 22 5.05 22 5.05 5,688 5,932 448 112.8 0.0 4.3 Mount Druitt 55 15.46 60 15.89 16,566 17,602 619 256.8 2.8 6.3 Oakhurst 1 0.06 2 0.25 7,178 7,399 203 12.3 302.1 3.1 Plumpton 10 3.44 11 3.44 8,679 9,794 302 113.8 0.0 12.8 Prospect - Huntingwood - Arndell Park 51 10.99 60 17.51 4,832 5,069 1,765 99.2 59.3 4.9 Quakers Hill 27 4.63 32 5.36 27,211 28,843 974 55.0 15.9 6.0 Riverstone - Vineyard 0 0.00 15 1.94 6,483 9,433 2,401 8.1 0.0 45.5 Rooty Hill - Eastern Creek 59 16.79 85 21.24 14,878 16,501 2,596 81.8 26.5 10.9 Schofields - Rouse Hill 20 3.53 33 8.79 4,959 12,568 1,952 45.0 148.9 153.4 Seven Hills 21 6.18 26 8.93 19,436 20,637 953 93.7 44.4 6.2 Shalvey 1 0.13 1 0.13 3,618 3,656 158 8.0 0.0 1.1 Stanhope Gardens 9 2.69 10 3.48 8,515 9,833 284 122.5 29.3 15.5 The Ponds 2 0.32 9 1.26 4,970 10,867 326 38.7 297.5 118.7 Toongabbie 4 0.35 5 0.47 4,714 5,301 170 27.9 35.5 12.5 Tregear 3 0.37 3 0.37 4,060 4,198 165 22.4 0.0 3.4 Whalan 0 0.00 0 0.00 6,145 6,309 242 0.0 0.0 2.7 Willmot 0 0.00 0 0.00 2,566 2,607 91 0.0 0.0 1.6 Woodcroft 2 0.54 2 0.54 6,730 6,992 172 31.3 0.0 3.9

In the Blacktown LGA, the area within carparks covered by green infrastructure was 0.5 ha in 2010 and 1.6 ha in 2019, representing a net increase of 1.1 ha (Table 3.7). The largest contributor to this increase was Glenwood, where green carpark infrastructure increased by 0.55 ha. In total, 339 trees were added to carparks between 2010 and 2019 across the LGA of Blacktown, with Glenwood again leading this trend by having added 85 new trees. However, at the same time, Blacktown CBD had lost 39 trees from their carparks, the single largest loss of trees in any of the 39 suburbs (Table 3.7). Synchronous to the net increase of trees, the area

36 of carpark space that was shaded by trees increased from 1.7 ha to 1.8 ha. Yet, as a result of the large increase of overall carparking space, the relative area shaded by trees declined from 0.015% to 0.012%. This net decline is also captured in the number of trees per hectare carparking space, declining from 9.5 trees ha-1 in 2010 to 9.2 trees ha-1 in 2019.

Table 3.7: Status of Green Infrastructure in the Blacktown carpark in 2010 and 2019.

2010 2019 Green No. of Tree shade Green No. of Tree shade area (ha) trees Area (ha) area (ha) trees Area (ha) Acacia Gardens- Parklea 0.00 16 0.03 0.03 31 0.03 Bidwill 0.01 3 0.00 0.01 3 0.00 Blackett 0.00 0 0.00 0.00 0 0.00 Blacktown 0.05 136 0.23 0.11 97 0.14 Bugarribee 0.00 0 0.00 0.00 10 0.01 Colebee 0.00 0 0.00 0.02 33 0.06 Dean Park 0.00 0 0.00 0.00 0 0.00 Dharruk 0.02 14 0.01 0.02 14 0.01 Doonside 0.00 6 0.02 0.00 6 0.02 Emerton 0.01 14 0.02 0.01 14 0.02 Glendenning 0.01 10 0.01 0.01 10 0.01 Glenwood 0.04 21 0.02 0.06 106 0.02 Hassal Grove 0.00 4 0.01 0.00 4 0.01 Hebersham 0.00 0 0.00 0.00 2 0.01 Kellyville Ridge 0.00 0 0.00 0.01 0 0.00 kings Langley 0.00 0 0.00 0.00 0 0.00 Kings Park 0.00 5 0.01 0.00 5 0.01 Lalor Park 0.00 0 0.00 0.00 0 0.00 Lethbridge park 0.00 0 0.00 0.00 0 0.00 Marayong 0.00 5 0.01 0.00 5 0.01 Marsden Park- Shannes Park 0.00 0 0.00 0.11 79 0.04 Minchinbury 0.01 95 0.07 0.01 95 0.07 Mount Druitt 0.08 122 0.18 0.08 127 0.18 Oakhurst 0.00 0 0.00 0.00 0 0.00 Plumpton 0.02 40 0.02 0.02 40 0.02 Prospect - Huntingwood - Arndell Park 0.08 109 0.16 0.09 138 0.18 Quakers Hill 0.02 30 0.06 0.03 35 0.07 Riverstone - Vineyard 0.00 0 0.00 0.03 11 0.02 Rooty Hill - Eastern Creek 0.08 228 0.27 0.09 260 0.28 Schofields - Rouse Hill 0.07 40 0.06 0.20 80 0.08 Seven Hills 0.00 59 0.29 0.00 67 0.30 Shalvey 0.00 2 0.00 0.00 2 0.00 Stanhope Gardens 0.02 97 0.22 0.02 109 0.22 The Ponds 0.00 0 0.00 0.04 12 0.01 Toongabbie 0.00 6 0.01 0.00 6 0.01 Tregear 0.00 0 0.00 0.00 0 0.00 Whalan 0.00 0 0.00 0.00 0 0.00 Willmot 0.00 0 0.00 0.00 0 0.00 Woodcroft 0.00 5 0.01 0.00 5 0.01

A positive and significant correlation (p <0.0001) between the change in population and change in carparking area was identified for this LGA (Figure 3.10). Two of the suburbs (Bidwill and Emerton) showed a decrease in population with no change in parking area. Suburbs like Prospect, Huntingwood and Arndell Park showed a drastic change of 6.5 ha of carparking area increment with only a small rise in local population of 237 people. The suburb of Marsden Park/Shanes Park did increase both its population (by 6,655 people) and its carpark area (by 14.2 ha) between 2010/12 and 2018/19.

Figure 3.10: Relationship between population growth between 2012 and 2018 and the change in carparking area from 2010 to 2019 across the 30 suburbs of Blacktown City. The green circles highlight negative values that indicate a decline in either population or carparking area. The dotted line shows the linear correlation.

3.3.2 Campbelltown Campbelltown City is located in the south west of the Sydney Basin, between 30 and 55 kilometres from the Sydney CBD (Figure 3.11). In 2012, 152,425 lived in the LGA of Campbelltown City, which covered an area of 31,133 hectares across 24 suburbs (see Figure S2). By, 2018, the population had increased significantly (p <0.001) to 167,930.

Population density rose from 4.9 people per hectare in 2012 to 5.4 people per hectare in 2018. There is an increase in population in Campbelltown LGA as a whole, however, this increment is not seen across its suburbs. The average relative population increase is 7.03%. The highest increase in the population of a single suburb was Glenfield where 8,788 residents were recorded in 2012 and 12,082 in 2018, a change of +37%. Between 2012 and 2018, the population in all suburbs increased with five exceptions. The population of Airds declined by 14%, Claymore by 18%, Eschol by 3%, Kearns by 1%, and that of Raby by 0.5% (Table 3.8).

Figure 3.11: Location of carparks across the LGA of Campbelltown. The boundary of the LGA is depicted as a blue line. The red dots show the locations of carparks across the LGA. The insert in the top left shows the location of the LGA (marked in yellow) in the larger context of the Sydney Basin.

Across the LGA, 282 carparks were identified and analysed for the timepoints of 2010 and 2019 (Table 3.8) 26 of these carparks covering 89 ha were classified as “small”. Campbelltown LGA forms with the combination of urban transformation around the LGA rural and peri-urban to urban land uses (Figure 3.10). It is mostly concentrated around the suburbs of Campbelltown, Ingleburn and Minto.

The total area covered by car parks increased from 83 ha in 2010 to 89 ha in 2019, representing an addition of 6 ha, or 8%. The average area covered by carparks across the 24 suburbs of Campbelltown LGA was 28.68 m2 ha-1. Campbelltown CBD had the largest proportion of carparks, covering 357 m2 ha-1. The overall largest increase in carpark area between 2010 and 2019 was observed for Campbelltown CBD where the number of carparks changed from 71 to 77, and the area covered rose from 37 to 40 ha. Between 2010 and 2019, the area covered by carparks remained unchanged in 12 of the 26 suburbs. Among these are 5 suburbs which did not have any car parking space.

Table 3.8: Carparks, population, and their changes between 2010 and 2019 across the suburbs of Campbelltown.

2010 2019 Ratio of Relative Parking to Parking Relative No. of Parking No. of Parking Population Population Suburb Suburb area area Change Population Carparks area (ha) Carparks area (ha) (2012) (2018) Area (ha) (m² ha¯¹) (% ) Change (% ) Airds 4 0.42 5 0.68 3,552 3,069 241 28.4 62.5 -13.6 Ambarvale 11 1.52 11 1.52 7,577 7,692 287 52.9 0.0 1.5 Blair Athol 0 0.00 0 0.00 2,825 3,173 89 0.0 0.0 12.3 Blairmount 0 0.00 0 0.00 536 596 345 0.0 0.0 11.2 Bradbury 11 1.78 9 1.19 8,991 9,230 359 33.1 -33.1 2.7 Campbeltown 71 37.27 77 39.83 11,046 14,193 1,114 357.5 6.9 28.5 Claymore 0 0.00 0 0.00 3,292 2,697 136 0.0 0.0 -18.1 Eagle Vale 5 1.28 5 1.28 5,882 6,004 249 51.3 0.0 2.1 Eschol 4 0.81 4 0.81 2,731 2,653 272 29.8 0.0 -2.9 Glen Alpine 2 0.52 2 0.52 4,841 4,924 294 17.8 0.0 1.7 Glenfield Bardia 10 2.10 10 2.41 8,788 12,082 910 26.5 14.5 37.5 Ingelburn 35 9.74 42 11.29 14,478 16,399 1,239 91.1 15.9 13.3 Kearns 3 0.56 3 0.56 2,874 2,832 236 23.8 0.0 -1.5 Leumeah 15 6.92 16 7.60 9,813 10,245 448 169.7 9.9 4.4 Macquaire Field 20 4.80 23 5.42 13,918 14,737 882 61.4 12.9 5.9 Macquaire Links 0 0.00 0 0.00 1,182 1,447 163 0.0 0.0 22.4 Minto 32 9.41 33 9.67 10,992 13,860 951 101.7 2.8 26.1 Raby 9 1.98 11 2.30 6,148 6,116 261 87.9 15.8 -0.5 Rosemeadow 7 1.33 10 1.72 8,011 8,123 301 57.0 29.0 1.4 Rural Residential 0 0.00 0 0.00 2,659 2,974 21,135 0.0 0.0 11.8 Ruse 2 0.31 2 0.31 5,712 5,759 260 11.8 0.0 0.8 St Andrews 3 0.68 3 0.68 7,479 7,990 297 23.0 0.0 6.8 St Helens Park 5 0.97 7 1.24 6,553 6,926 514 24.1 27.9 5.7 Woodbine 2 0.24 2 0.27 2,708 2,952 150 17.8 12.6 9.0

The area within carparks covered by green infrastructure was 0.29 ha in 2010 and 0.26 ha in 2019, representing a slight decrease of 0.03 ha (Table 3.9). There was no change in number of trees but the tree shade area has been increased from 0.73ha to 1.03 ha. The largest contributor for the increase in tree shade area was Minto where it increased from 0.09 ha to 0.2 ha. The relative area shaded by trees has very slightly increased from 0.008% to 0.01%. Yet, the number of trees per hectare carparking space declined from 8.7 trees ha-1 in 2010 to 8.1 trees ha-1.

Table 3.9: Status of Green Infrastructure in the Campbelltown carpark in 2010 and 2019.

2010 2019 Green No. of Tree shade Green No. of Tree shade area (ha) trees Area (ha) area (ha) trees Area (ha) Airds 0.00 0 0.00 0.00 0 0.00 Ambarvale 0.01 0 0.00 0.01 0 0.00 Blair Athol 0.00 0 0.00 0.00 0 0.00 Blairmount 0.00 0 0.00 0.00 0 0.00 Bradbury 0.01 11 0.01 0.01 11 0.01 Campbeltown 0.07 330 0.37 0.07 324 0.36 Claymore 0.00 0 0.00 0.00 0 0.00 Eagle Vale 0.00 31 0.02 0.01 31 0.08 Eschol 0.02 2 0.00 0.02 2 0.01 Glen Alpine 0.02 1 0.01 0.02 1 0.01 Glenfield Bardia 0.01 0 0.00 0.01 10 0.01 Ingelburn 0.08 61 0.05 0.04 61 0.10 Kearns 0.00 5 0.00 0.00 5 0.01 Leumeah 0.00 16 0.01 0.00 16 0.01 Macquaire Field 0.02 87 0.08 0.02 82 0.06 Macquaire Links 0.00 0 0.00 0.00 0 0.00 Minto 0.03 109 0.09 0.03 109 0.15 Raby 0.03 23 0.02 0.03 23 0.03 Rosemeadow 0.01 21 0.03 0.01 21 0.09 Rural Residential 0.00 0 0.00 0.00 0 0.00 Ruse 0.00 0 0.00 0.00 0 0.00 St Andrews 0.00 6 0.01 0.00 6 0.01 St Helens Park 0.00 19 0.02 0.00 19 0.09 Woodbine 0.00 0 0.00 0.00 0 0.00

The change in car parking area in relation to the change in population is shown in (Figure 3.12). A positive and significant correlation (p <0.001) between the change in population and change in carparking area was identified for this LGA. Exceptions to this trend are two suburbs (Airds and Raby) where the population declined, yet the area of carparks increased. Airds decreased its population by 13.6%, the highest decrease in population in all suburbs. Three suburbs (Claymore, Eschol, and Kearns) showed a decrease in population with no changes in the area taken up by carparks. Another exception was seen in Bradbury, the area of carparks decreased while its population has increased.

Figure 3.12: Relationship between population growth between 2012 and 2018 and the change in carparking area from 2010 to 2019 across the 24 suburbs of Campbelltown City. The green circles highlight negative values that indicate a decline in either population or carparking area. The dotted line shows the linear correlation.

3.3.3 Camden Camden is located in the south-west of Sydney Basin, approximately 65 km from the Sydney CBD (Figure 3.13) shows it to be combination of rural and peri-urban to urban land uses. In 2012, 61,127 people lived in the LGA of Camden City, which covered an area of 20,096 ha across 12 suburbs (see Figure S3). By 2018, the population had increased significantly (p <0.01) to 94,029.

Population density rose from 4.1 people per hectare in 2012 to 6.5 people per hectare in 2018. There is an increase in population in Camden LGA as a whole, however, this increment is not seen across all of its suburbs. The average relative population increase is 175%. The highest increase in the population of a single suburb was in Gledswood Hills –Gregory Hills where 569 residents were recorded in 2012 and 7093 in 2018, representing a change of +1,146%. Between 2012 and 2018, the population in all suburbs increased with one exception. The population of Camden declined by 1.98% (Table 3.10).

Figure 3.13: Location of carparks across the LGA of Camden. The boundary of the LGA is depicted as a blue line. The red dots show the locations of carparks across the LGA. The insert in the top left shows the location of the LGA (marked in yellow) in the larger context of the Sydney Basin.

Across the LGA, 215 carparks were identified and analysed for the timepoints of 2010 and 2019 (Table 3.10). 102 of these carparks were classified as ‘small’. The concentration of carparks was greatest in the Camden and Narellan, however, clusters of new carparks were clearly identifiable in the Gledswood Hills–Gregory Hills (Figure 3.13).

The total area covered by car parks increased from 25.9 ha in 2010 to 48.9 ha in 2019, representing an addition of 23 ha, or 89%. The overall largest increase in carpark area between 43

2010 and 2019 was observed for Gledswood Hills – Gregory Hills where the number of carparks changed from 8 to 32, the area covered from 3.2 to 10.2 ha, increasing the ratio of carparking area to suburb area from 32.3m2 ha-1 to 102 m2 ha-1.

Between 2010 and 2019, the area covered by carparks remained unchanged in 3 of the 12 suburbs. The number of carparks ranged from 0 to 54 amongst the suburbs. The average amount of carparks per suburb was 12 (±5) in 2010, which changed to 18 (±5) in 2019. The highest number of carparks in an individual suburb in 2019 was in Narellan-Smeaton, where 63 carparks covered a total area of 14.2 ha, representing an increase of 5.7% compared to 2010 (Table 3.10). Although the suburb of Camden itself had the highest number of carparks (n = 45), the are taken up by these carparks was with 5.3 ha much less than in Gledswood Hills- Gregory Hills where 32 carparks occupied an area of 10.2 ha. There was an increase in carpark area in across the LGA of Camden, including Leppington and Oran Park that had not carparks in 2010 but in 2019 had 5 and 23, respectively.

Table 3.10: Carparks, population, and their changes between 2010 and 2019 across the suburbs of Camden LGA. 2010 2019 Ratio of Relative Parking to Parking Relative No. of Parking No. of Parking Population Population Suburb Suburb area area Change Population Carparks area (ha) Carparks area (ha) (2012) (2018) Area (ha) (m² ha¯¹) (% ) Change (% ) Camden 45 5.19 45 5.26 3,381 3,314 445 118.3 1.5 -2.0 Bringelly-Cobbitty 2 0.28 3 0.37 1,640 3,844 7,371 0.5 35.1 134.4 Camden South 6 1.35 6 1.35 4,550 4,706 427 31.6 0.0 3.4 Currans Hills 4 0.08 4 0.32 5,117 5,815 360 9.0 327.7 13.6 Eldeslie 9 2.87 11 2.97 4,773 7,193 512 58.0 3.4 50.7 Gledswood hills -Gregory 8 3.23 32 10.18 569 7,093 999 101.9 214.9 1146.6 Grassmere 5 0.24 5 0.24 2,897 3,107 1,661 1.4 0.0 7.2 Harrington Park- Krikham 1 0.28 1 0.28 9,078 13,253 1,248 2.2 0.0 46.0 Leppington 0 0.00 5 4.96 4,815 9,272 3,355 14.8 0.0 92.6 Mounta Annan 13 3.59 16 3.81 10,882 12,779 832 45.8 6.3 17.4 Narellan- Smeaton 54 8.60 63 14.24 3,455 3,653 907 157.0 65.6 5.7 Narellan Vale 0 0.00 0 0.00 7,280 7,855 257 0.0 0.0 7.9 Oran Park 0 0.00 23 3.86 866 7,287 1,331 29.0 0.0 741.5 Spring Farm 1 0.43 4 1.37 1,886 5,364 647 21.1 221.4 184.4 The area within carparks covered by green infrastructure was 1.1 ha in 2010 and 1.7 ha in 2019, representing a net increase of 0.6 ha (Table 3.11). In total, 99 trees were added to carparks between 2010 and 2019 across the LGA of Camden. Synchronous to the net increase of trees, the area of carpark space that was shaded by trees increased from 0.7 ha to 0.8 ha. Yet, as a result of the large increase of overall carparking space, the relative area shaded by trees declined from 0.02% to 0.01%. This net decline is also captured in the number of trees per hectare carparking space, declining from 4.5 trees ha-1 in 2010 to 4.4 trees ha-1. The relative area shaded by trees and number of trees did not show any difference between 2010 and 2019.

Table 3.11: Status of Green Infrastructure in the Camden carpark in 2010 and 2019. 2010 2019 Green No. of Tree shade Green No. of Tree shade area (ha) trees Area (ha) area (ha) trees Area (ha) Camden 0.12 50 0.16 0.11 50 0.26 Bringelly-Cobbitty 0.03 5 0.01 0.03 5 0.01 Camden South 0.03 10 0.06 0.03 10 0.09 Currans Hills 0.00 0 0.00 0.03 0 0.00 Eldeslie 0.00 16 0.14 0.04 10 0.07 Gledswood hills -Gregory 0.15 0 0.00 0.39 80 0.02 Grassmere 0.00 0 0.00 0.00 0 0.00 Harrington 0.02 0 0.00 0.02 0 0.00 Leppington 0.00 0 0.00 0.06 0 0.00 Mounta Annan 0.14 20 0.05 0.14 20 0.09 Narellan- Smeaton 0.46 20 0.20 0.50 20 0.20 Oran Park 0.00 0 0.00 0.20 7 0.01 Spring Farm 0.15 0 0.00 0.16 18 0.02 The changes in the area taken up by carparks and that of the local population were highly significant (p <0.001) (Figure 3.14). A decrease in local population with a simultaneous increase in carparking space was only observed for the suburb of Camden. All other suburbs showed increases in both, population and the area of carparks. The single largest change of more than 7 ha was noted for Gledswood Hillls-Gregory Hills. Interestingly, in Narellan- Smeaton had an increase of 5.6 ha parking space yet had a population of only 907.

Figure 3.14: Relationship between population growth between 2012 and 2018 and the change in carparking area from 2010 to 2019 across the 12 suburbs of Camden City. The green circle highlights negative values that indicate a decline in either population or carparking area. The dotted line shows the linear correlation.

3.3.4 Cumberland

The Cumberland Council area is in Sydney's central western suburbs, about 25 kilometres from the Sydney CBD (Figure 3.15). The LGA of Cumberland City covered an area of 7167 hectares, across 13 suburbs (see Figure S4).

Figure 3.15: Location of carparks across the LGA of Cumberland. The boundary of the LGA is depicted as a blue line. The red dots show the locations of carparks across the LGA. The insert in the top left shows the location of the LGA (marked in yellow) in the larger context of the Sydney Basin.

In 2012, the population of Cumberland was 207,528. By 2018, the population had increased significantly (p<0.0001) to 236,599, which represents an increase of nearly 16% and affected

46 all suburbs (Table 3.12). Population density rose from 23.7 people per hectare in 2012 to 27.1 people per hectare in 2018. The highest increase in population of a single suburb was in Lidcombe-Rookwood where 17,881 residents were recorded in 2012 and 22,092 in 2018, a change of +23.5%. Across the LGA, 288 carparks were identified and analysed for 2010 and 311 carparks for 2019 (Table 3.12). Out of these carparks 33 in 2010 and 32 in 2019 were classified as ‘small’. The concentration of carparks was high in the west and south-west where large industrial estates were located. The remaining area of Cumberland had a relatively even spread of carparks (Figure. 3.15). It is the only LGA with all the suburbs having carparking area.

The total area covered by car parks increased from 83.4 ha in 2010 to 92.8 ha in 2019. This represented an addition of 9 ha, or 15%, leading to a significant increase in car parking area (p <0.04). The carpark area to suburb area ratio was highest in Pemulwuy with 258 m2 ha-1 and least with 21.3 m2 ha-1 in Westmead-May’s Hill. Guildford West-Woodpark-Smithfield- Yennora had the largest proportion of carparks, covering 22 ha of urban space. The overall largest increase in carpark area between 2010 and 2019 was observed for Merrylands-Holroyd, where the number of carparks changed from 23 to 26, and the area covered by them from 9 to 12 hectare. This led to an increase in the ratio of carpark area to suburb area from 100 m2 ha-1 to 135 m2 ha-1. Between 2010 and 2019, the area covered by carparks remained unchanged in 5 of the 13 suburbs. Across all suburbs, the number of carparks ranged from 1 to 74. Each of the 13 suburbs had an average of 19 carparks in 2010 and 20 in 2019. Table 3.12: Carparks, population, and their change between 2010 and 2019 across the suburbs of Cumberland LGA. 2010 2019 Ratio of Parking to Relative Relative No. of Parking No. of Parking Population Population Suburb Suburb area parking area population Carparks area (ha) Carparks area (ha) (2012) (2018) Area (ha) (m² ha¯¹) change (% ) change(% ) Berala 1 0.51 1 0.51 8,927 9,566 207 24.8 0.0 7.2 Auburn 42 12.00 46 14.37 36,149 41,448 765 187.8 22.5 14.7 Girraween - Toongabbie 11 3.26 12 3.41 6,850 8,279 291 117.3 4.7 20.9 Granville 8 5.21 8 5.21 10,428 11,611 231 225.6 0.0 11.3 Greystanes 18 3.53 19 3.76 23,176 24,365 886 42.5 6.7 5.1 Guildford West - Woodpark - Smithfield- Yennora 74 22.00 75 22.03 27,312 31,481 1,425 154.6 0.1 15.3 Lidcombe - Rookwood 49 11.26 54 12.60 17,881 22,092 917 137.4 11.9 23.6 Merrylands-Holoroyd 23 8.91 26 12.11 36,274 41,410 893 135.9 35.9 14.5 Pemulwuy-Prospect 30 8.80 36 9.92 3,567 5,383 384 258.2 12.7 50.9 Pendle Hill 3 0.32 3 0.32 5,789 6,185 130 24.8 0.0 6.8 Regents Park 7 1.04 7 1.04 4,447 4,649 146 71.5 0.0 4.5 South Granville - Chester Hill 9 2.52 11 2.75 6,085 7,161 270 101.7 9.1 17.7 Wentworthville 12 3.93 12 4.01 13,353 15,093 374 107.2 2.1 13.0 Westmead - Mays Hill 1 0.34 1 0.34 7,426 8,475 159 21.3 0.0 14.1

The area within carparks covered by green infrastructure was 0.43 ha in 2010 and 0.38 ha in 2019, representing a net decrease of 0.05 ha (Table 3.13). In total, 62 trees were added to carparks between 2010 and 2019 across Cumberland LGA. These additions resulted in an expansion of the area shaded in carparks from 0.7 ha to 0.9 ha. The highest number of additional trees was observed in the suburb of Pemulwuy-Prospect where 88 trees were planted in carparks. However, trees were also lost in carparks, particularly around Lidcombe and Wentworthville. Yet, as a result of the large increase of overall carparking space, the relative area shaded by trees did not change between 2010 and 2019 across the LGA of Cumberland and remained with 0.01% very low.

Table 3.13: Status of Green Infrastructure in the Cumberland carpark in 2010 and 2019. 2010 2019 Green No. of Tree shade Green No. of Tree shade area (ha) trees Area (ha) area (ha) trees Area (ha) Berala 0.03 0 0.00 0.03 0 0.00 Auburn 0.03 50 0.08 0.03 53 0.09 Girraween - Toongabbie 0.00 0 0.00 0.00 0 0.00 Granville 0.04 41 0.04 0.04 41 0.09 Greystanes 0.01 61 0.08 0.01 61 0.10 Guildford West - Woodpark - Smithfield-Yennora 0.08 185 0.18 0.02 192 0.21 Lidcombe - Rookwood 0.13 145 0.19 0.13 116 0.14 Merrylands-Holoroyd 0.05 71 0.09 0.05 76 0.10 Pemulwuy-Prospect 0.02 116 0.08 0.04 204 0.22 Pendle Hill 0.00 5 0.01 0.00 5 0.01 Regents Park 0.00 0 0.00 0.00 0 0.00 South Granville - Chester Hill 0.00 25 0.03 0.00 25 0.03 Wentworthville 0.00 31 0.03 0.00 22 0.01 Westmead - Mays Hill 0.09 0 0.00 0.09 0 0.00 The concurrent changes in car parking area and those in the population of Cumberland were positive and significant (p <0.001) (Figure 3.16). It showed the relation of increase in the carparking area with the increase in population. Suburbs as (Berala, Granville, Pendle Hill, Regents Park and Westmead-Mays Hill) showed no changes in car park even with the increase in population. There was no suburb in Cumberland with a decline in either population or carparking area.

Figure 3.16: Relationship between population growth between 2012 and 2018 and the change in carparking area from 2010 to 2019 across the 13 suburbs of Cumberland City.

3.3.5 Parramatta The Parramatta Council area is a major commercial suburb located in Sydney's central western suburbs, about 23 kilometres from the Sydney CBD (Figure 3.17). In 2012, 208,182 people lived in the LGA of Parramatta, which covered an area of 8,375 hectares. By 2018, the population had increased significantly (p<0.001) to 251,065.

Population density rose from 25 people per hectare in 2012 to 30 people per hectare in 2018. The change in population was not uniform across the suburbs of Parramatta City. The average population increase across the LGA was 44.59%. The highest increase in the population of a single suburb was in Sydney Olympic Park (+641%), the lowest in North Rocks (+3.7%). In the central CBD of Parramatta, the population rose from 21,938 residents in 2012 to 30,167 in 2018 (+37.5%). Between 2012 and 2018, the population in all 27 suburbs (see Figure S5) had increased (Table 3.14).

Figure 3.17: Location of carparks across the LGA of Parramatta. The boundary of the LGA is depicted as a blue line. The red dots show the locations of carparks across the LGA. The insert in the top left shows the location of the LGA (marked in yellow) in the larger context of the Sydney Basin.

Across the LGA, 458 carparks were identified and analysed for the timepoints of 2010 and 449 in 2019 (Table 3.14). 141 in 2010 and 132 in 2019 of these carparks were classified as ‘small’. The total area covered by car parks increased from 106.6 ha in 2010 to 115.4 ha in 2019, representing an addition of 8.8 ha, or 8.2%. The ratio of parking area to suburb area was highest in Westmead where 1073 m2 ha-1 were covered by carparks concentrated around the large hospital complex. Notably, four suburbs had not a single carpark. These were Telopea,

Oatlands, North Parramatta, and Dundas Valley. Sydney Olympic Park had the largest proportion of carparks, covering 29.5 ha of area or 4% of its total area of 703 ha.

The overall largest increase in carpark area between 2010 and 2019 was observed at Westmead, where the number of carparks changed little (2010: 34; 2019: 36), yet the area covered increased notably from 7.3 to 16.5 hectare. This change represented an increase of the ratio of carpark-to-suburb area from 478 m2 ha-1 to 1073 m2 ha-1. Between 2010 and 2019, the area covered by carparks remained unchanged in 12 of the 27 suburbs. In 8 of the 27 suburbs, the area of carparks declined (Table 3.14). The largest decline was observed for Parramatta CBD where five carparks disappeared, representing an area of 1.3 ha. Across the LGA of Parramatta, the average number of carparks in each suburb was 19 and did not change from 2010 to 2019.

Table 3.14: Carparks, population, and their changes between 2010 and 2019 across the suburbs of Parramatta LGA.

2010 2019 Ratio of Parking to Relative Relative No. of Parking No. of Parking Population Population Suburb Suburb area parking area population Carparks area (ha) Carparks area (ha) (2012) (2018) Area (ha) (m² ha¯¹) change (% ) change(% ) Beecroft 0 0 0 0 2530 2725 109 0 0 0 Camellia 2 1.21 2 1.21 4 5 74 163.4 0.0 25.0 Carlingford 10 3.10 10 3.10 23,107 27,050 845 36.6 0.0 17.1 Constitution Hill 1 0.10 1 0.10 4,139 4,331 123 7.8 0.0 4.8 Dundas 5 5.72 5 5.72 4,306 5,130 143 400.2 0.0 19.3 Dundas Valley 0 0.00 0 0.00 5,233 5,816 176 0.0 0.0 11.3 Eastwood 20 2.85 18 2.02 4,100 4,863 116 174.4 -29.0 18.6 Epping 19 2.83 15 2.78 21,812 26,904 688 40.4 -1.7 23.3 Ermington - Melrose Park 33 5.14 30 4.44 9,981 11,745 429 103.5 -13.5 17.7 Granville (part) - Clyde 17 1.82 17 1.82 4,410 4,833 164 111.2 0.0 9.6 Harris Park 1 0.50 1 0.50 5,448 6,379 65 77.2 0.0 17.1 Newington 11 2.70 11 2.57 5,516 6,396 90 285.9 -4.8 16.0 North Parramatta 0 0.00 0 0.00 13,507 14,366 524 0.0 0.0 6.4 North Rocks 38 5.31 40 6.03 7,694 7,980 466 129.4 13.5 3.7 Northmead 12 1.39 12 1.39 10,767 12,487 435 32.0 0.0 16.0 Oatlands 5 0.00 6 0.00 5,655 6,136 245 0.0 0.0 8.5 Old Toongabbie 20 0.90 20 1.47 3,165 3,314 127 115.5 63.3 4.7 Parramatta 43 17.70 38 16.45 21,938 30,167 558 294.8 -7.1 37.5 Rosehill 20 5.63 19 5.49 3,163 4,516 350 156.8 -2.5 42.8 Rydalmere 12 2.10 15 4.07 6,620 7,302 357 114.1 94.4 10.3 Silverwater 69 7.27 69 7.11 3,409 4,592 269 264.4 -2.2 34.7 Sydney Olympic Park 58 29.49 55 29.55 361 2,679 703 420.3 0.2 642.1 Telopea 0 0.00 0 0.00 4,845 5,907 154 0.0 0.0 21.9 Toongabbie 7 0.74 8 0.76 7,360 7,817 259 29.4 3.1 6.2 Wentworth Point 12 2.06 8 1.13 3,706 9,361 57 197.5 -45.4 152.6 Wentworthville - Pendle Hill 3 0.29 7 0.78 4,967 5,546 188 41.3 168.1 11.7 Westmead 34 7.36 36 16.53 8,387 10,062 154 1073.1 124.5 20.0 Winston Hills 6 0.42 6 0.42 12,191 12,811 457 9.2 0.0 5.1

Green infrastructure around carparks was 1.1 ha in 2010 and 1.9 ha in 2019, representing a net increase of 0.8 ha (Table 3.15). In total, 38 trees were added to carparks between 2010 and 2019 across the LGA of Parramatta. The growth of existing and addition of new trees resulted 51 in a net increase of 0.1 ha of shade provided by trees. The highest increase of trees has been observed in Rydalmere where 45 trees were planted in carparks. In contrast, the highest decline was observed in the Sydney Olympic Park where 25 trees were lost. The additions and losses of trees and carparks did cause a slight decline of 6.9 trees ha-1 in 2010 to 6.7 trees ha-1 in 2019.

Table 3.15: Status of Green Infrastructure in the Parramatta carpark in 2010 and 2019.

2010 2019 Green No. of Tree shade Green No. of Tree shade area (ha) trees Area (ha) area (ha) trees Area (ha) Beecroft 0.00 0.0 0.00 0.00 0.0 0.00 Camellia 0.00 11 0.01 0.00 11 0.01 Carlingford 0.00 23 0.04 0.00 23 0.04 Constitution Hill 0.00 0 0.00 0.00 0 0.00 Dundas 0.05 55 0.08 0.05 55 0.08 Dundas Valley 0.00 0 0.00 0.00 0 0.00 Eastwood 0.12 28 0.13 0.08 11 0.10 Epping 0.00 21 0.06 0.01 21 0.06 Ermington - Melrose Park 0.05 23 0.07 0.05 15 0.00 Granville (part) - Clyde 0.05 21 0.03 0.05 21 0.03 Harris Park 0.00 0 0.00 0.00 0 0.00 Newington 0.04 9 0.03 0.04 9 0.03 North Parramatta 0.00 0 0.00 0.00 0 0.00 North Rocks 0.12 9 0.02 0.18 39 0.05 Northmead 0.03 8 0.01 0.01 20 0.04 Oatlands 0.00 0 0.00 0.00 0 0.00 Old Toongabbie 0.00 11 0.03 0.00 20 0.04 Parramatta 0.01 31 0.20 0.01 14 0.10 Rosehill 0.01 56 0.22 0.01 39 0.12 Rydalmere 0.00 26 0.04 0.02 71 0.06 Silverwater 0.02 52 0.16 0.02 56 0.20 Sydney Olympic Park 0.40 287 0.45 0.49 262 0.67 Telopea 0.00 0 0.00 0.00 0 0.00 Toongabbie 0.00 0 0.00 0.00 0 0.00 Wentworth Point 0.02 7 0.02 0.01 7 0.05 Wentworthville - Pendle Hill 0.00 7 0.01 0.00 7 0.01 Westmead 0.17 56 0.19 0.18 78 0.23 Winston Hills 0.00 1 0.01 0.00 1 0.01 The correlation of population changes and carparking area change were not significant, with the exception of decrease in parking area space even during the population increase (Figure 3.18). The suburbs of Eastwood, Epping, Ermington/Melrose Park, Rosehill, Parramatta, Newington, Silverwater and Wentworth Point showed a decline in the carparking area even with the increase in population. The highest was seen in Wentworth point with decrease in carparking space by 45% even with the increase in population of 152%.

Figure 3.18: Relationship between population growth between 2012 and 2018 and the change in carparking area from 2010 to 2019 across the 27 suburbs of Parramatta City. The green circle highlights negative values that indicate a decline in either population or carparking area. The dotted line shows the linear correlation.

3.3.6 Penrith The Penrith Council area is located at the edge of the Blue Mountains in the far west of the Sydney Basin and about 50 kilometres from the Sydney CBD (Figure 3.19). The area covered by the LGA of Penrith was 404,770 hectares. In 2012 the population across the 28 suburbs (see Figure S6) making up the LGA was 187,281. By 2018, the population had significantly (p <0.001) increased to 208,947. Population density rose from 4.8 people per hectare in 2012 to 5.3 people per hectare in 2018.

The average relative population increase was 202.87%. Out of 28 suburbs, 3 showed a decline in population (Table 3.16). The highest decline in population was in Erskine Park where 6835 residents were recorded in 2012 and 6654 in 2018, a change of -2.65%. The highest increase in the population of a single suburb was in Jordan Springs where 114 residents were recorded in 2012 and 6558 in 2018, a change of +5652% (Table 3.16).

Figure 3.19: Location of carparks across the LGA of Penrith. The boundary of the LGA is depicted as a blue line. The red dots show the locations of carparks across the LGA. The insert in the top left shows the location of the LGA (marked in yellow) in the larger context of the Sydney Basin.

Across the LGA, 284 carparks were identified and analysed for the timepoints of 2010 and 339 in 2019 (Table 3.16). 56 in 2010 and 71 in 2019 of these carparks were classified as ‘small’. The total area covered by car parks increased from 77.7 ha in 2010 to 90 ha in 2019, representing an addition of 12.2 ha, or 15.7%. The urbanised zones of the Penrith LGA are located in its central section, with the northern and southern parts being predominately rural (Figure 3.19).

Parking area to suburb area was highest in Jamisontown with 320.5 m2 ha-1 whereas Kingswood had the largest proportion of carparks, covering 14.6 ha. The overall largest increase in carparking area between 2010 and 2019 was observed for Erskine Park where the number of carparks changed from 10 to 24. This caused an expansion of carparking area from 2.6 to 5.6 hectare and an increase in the ratio of carparking area to suburb area from 31.4 m2 ha-1 to 67.05 m2 ha-1. Between 2010 and 2019, the area covered by carparks remained unchanged in 15 of the 27 suburbs. The average number of carparks across the suburbs of Penrith changed from 16 in 2010 to 18 in 2019.

Table 3.16: Carparks, population, and their changes between 2010 and 2019 across the suburbs of Penrith LGA.

2010 2019 Ratio of Parking to Relative Relative No. of Parking No. of Parking Population Population Suburb Suburb area parking area population Carparks area (ha) Carparks area (ha) (2012) (2018) Area (ha) (m² ha¯¹) change (% ) change(% ) Berkshire Park 0 0 0 0 1864 2213 1927 0 0 0 Cambridge Park 5 0.82 5 0.82 6,522 6,994 260 31.3 0.0 7.2 Castlereagh - Agnes Banks 0 0.00 0 0.00 1,623 1,817 4,354 0.0 0.0 12.0 Claremont Meadows 2 1.14 3 1.49 4,343 5,344 305 48.8 30.5 23.0 Colyton 7 2.07 7 2.07 8,303 8,781 339 61.0 0.0 5.8 Cranebrook 9 1.34 10 1.82 16,087 17,542 1,496 12.2 36.5 9.0 Emu Heights 0 0.00 0 0.00 3,417 3,369 346 0.0 0.0 -1.4 Emu Plains 0 0.00 0 0.00 8,433 8,567 801 0.0 0.0 1.6 Erskine Park 10 2.63 24 5.61 6,835 6,654 837 67.1 113.4 -2.6 Glenmore Park 10 1.82 13 2.24 21,595 24,310 1,120 20.0 23.3 12.6 Jamisontown 50 11.33 51 12.88 5,435 5,602 402 320.5 13.7 3.1 Jordan Springs 0 0.00 10 1.46 114 6,548 968 15.0 0.0 5652.6 Kingswood 44 12.16 53 14.63 9,653 11,944 648 225.7 20.3 23.7 Leonay 0 0.00 0 0.00 2,533 2,617 221 0.0 0.0 3.3 Llandilo 3 0.45 3 0.45 1,722 1,779 1,294 3.5 0.0 3.3 Londonderry 0 0.00 0 0.00 3,957 4,144 3,546 0.0 0.0 4.7 Luddenham - Wallacia 0 0.00 0 0.00 2,064 2,717 3,473 0.0 0.0 31.6 Mount Vernon - Kemps Creek - Badgerys Creek 10 2.61 10 2.61 1,793 1,900 3,658 7.1 0.0 6.0 Mulgoa 3 0.27 5 0.61 1,719 2,141 5,247 1.2 127.4 24.5 North St Marys 0 0.00 0 0.00 3,866 4,139 319 0.0 0.0 7.1 Orchard Hills 1 0.60 1 0.60 1,972 2,036 4,317 1.4 0.0 3.2 Oxley Park 3 0.65 3 0.65 2,951 3,289 123 52.5 0.0 11.5 Penrith 49 22.69 53 23.61 12,392 14,623 1,248 189.2 4.0 18.0 Regentville 0 0.00 0 0.00 792 791 123 0.0 0.0 -0.1 South Penrith 17 3.73 19 3.89 12,029 12,122 508 76.6 4.4 0.8 St Clair 20 2.63 20 2.63 20,481 20,542 719 36.6 0.0 0.3 St Marys 30 8.53 35 8.84 11,731 13,162 954 92.6 3.6 12.2 Werrington 11 2.30 14 3.09 4,016 4,422 450 68.6 34.4 10.1 Werrington Downs - Werrington County - Cambridge Gardens 0 0.00 0 0.00 9,094 9,121 399 0 0 0.3

The vegetated area in these carparks was 1.4 ha in 2010 and 1.7 ha in 2019 (Table 3.17). In total, 54 trees were added to carparks between 2010 and 2019 across the carparks of the LGA of Penrith. Additional trees and growth of the existing tree stock resulted in 0.1 ha more shade area. The highest number of new trees were observed in carparks in the area of Mount Vernon - Kemps Creek - Badgerys Creek where 45 trees were planted. However, carparks around St

Marys lost 14 trees at the same time, and the overall area shaded by trees remained unchanged. Given the significant increase in carparking space across the LGA, the low additions of trees meant that their relative presence in carparks declined from 7.11 trees ha-1 in 2010 to 6.75 trees ha-1 in 2019.

Table 3.17: Status of Green Infrastructure in the Penrith carpark in 2010 and 2019.

2010 2019 Green No. of Tree shade Green No. of Tree shade area (ha) trees Area (ha) area (ha) trees Area (ha) Berkshire Park 0.00 0.0 0.00 0.00 0.0 0.00 Cambridge Park 0.00 5 0.01 0.00 5 0.01 Castlereagh - Agnes Banks 0.00 0 0.00 0.00 0 0.00 Claremont Meadows 0.01 12 0.01 0.01 12 0.01 Colyton 0.00 18 0.07 0.00 18 0.07 Cranebrook 0.01 23 0.11 0.01 24 0.11 Emu Heights 0.00 0 0.00 0.00 0 0.00 Emu Plains 0.00 0 0.00 0.00 0 0.00 Erskine Park 0.03 12 0.02 0.06 43 0.05 Glenmore Park 0.03 16 0.01 0.03 26 0.03 Jamisontown 0.14 73 0.09 0.16 79 0.09 Jordan Springs 0.00 0 0.00 0.02 4 0.07 Kingswood 0.62 113 0.26 0.65 102 0.23 Leonay 0.00 0 0.00 0.00 0 0.00 Llandilo 0.01 6 0.01 0.01 4 0.01 Londonderry 0.00 0 0.00 0.00 0 0.00 Luddenham - Wallacia 0.00 0 0.00 0.00 0 0.00 Mount Vernon - Kemps Creek - Badgerys Creek 0.06 0 0.00 0.05 45 0.07 Mulgoa 0.00 0 0.00 0.00 0 0.00 North St Marys 0.00 0 0.00 0.00 0 0.00 Orchard Hills 0.00 10 0.02 0.00 10 0.02 Oxley Park 0.03 0 0.00 0.03 0 0.00 Penrith 0.13 129 0.58 0.27 117 0.51 Regentville 0.00 0 0.00 0.00 0 0.00 South Penrith 0.03 8 0.04 0.03 8 0.05 St Clair 0.01 45 0.19 0.01 45 0.19 St Marys 0.06 65 0.09 0.08 51 0.08 Werrington 0.22 18 0.06 0.26 14 0.02 Werrington Downs - Werrington County - Cambridge Gardens 0.00 0 0.00 0.00 0 0.00 As within most other investigated LGAs of Greater Western Sydney, the increase in carparking space between 2010 and 2019 was significantly correlated with the increase in local population (p <0.01) (Figure 3.20). While the population in Regentville, Erskine Park and Emu Heights declined, their parking area increased. Especially dramatic was this trend in

Erskine Park, where the population declined from 6,835 people in 2012 to 6,654 people in 2018, while the area used for carparks increased by 3 ha from 2010 to 2019.

Figure 3.20: Relationship between population growth between 2012 and 2018 and the change in carparking area from 2010 to 2019 across the 28 suburbs of Penrith City. The green circle highlights negative values that indicate a decline in either population or carparking area. The dotted line shows the linear correlation.

4 Discussion

Aerial images show the extensive changes that happened across Greater Western Sydney during the past 10 years. The dramatic transformation over the past decade has resulted in additional 301 new carparking spaces covering and additional 104 ha of land that was transformed from pervious greenfield to impervious carparking space. Population growth of the studied area showed a parallel increase with the expanding carpark area. The six studied LGAs across Greater Western Sydney contained 143 suburb areas and the local populations of most of these suburbs increased with some exceptions. On average, between 2012 and 2018 population growth among the six studied LGAs was 17%, with the lowest east increment in Campbelltown (9.23%) and the highest increment in Camden (60.80%). Some densely populated suburbs, mostly in the LGA of Parramatta displayed the unexpected trend of a decline in the area taken up by carparks. Most likely, carparks in these suburbs were converted to medium- or high-density housing estates in response to high land value. These new housing estates usually feature underground parking facilities and were thus not captured in the present study.

Development in Western Sydney Greater Western Sydney houses the third-largest economy in Australia (Montoya 2015). According to projections by the Commonwealth Department of Planning and Environment, the population of Greater Western Sydney is expected to reach 2.92 million in 2031, which means population of the region will grow by 1.9% every year in the coming decade. This growth rate is considerably higher than the average annual growth rate between 2004 and 2014, which was just 1.62%. The fast population growth across the towns and suburbs of western Sydney can also be grasped when looking east. Annual population growth in this part of the Sydney Basin is predicted to be less than 1.3% in the 2020s.

4.1 Trends across Western Sydney

Population Populations do not grow at the same rate across western Sydney. Among the studied LGAs, Blacktown, Camden, Cumberland, and Parramatta grew most between 2012 and 2018 (increasing by 15%, 61%, 14%, 21% respectively) whereas, slower population growth was noted for Campbelltown (9%) and Penrith (12%). Even more insightful were the analyses at 58 the suburb level, revealing substantial variation in rates of population growth over the past decade.

The highest population increment for an individual suburb was noted for Jordan Springs in the LGA of Penrith. In 2012 just 114 people were counted by the Census for this suburb. In 2018, Jordan Springs was the new home for 6,558, representing a relative population increase of 5653%. This dramatic increase in local population and the associated conversion of greenfield to grey infrastructure can easily be seen in aerial images (Figure 4.1). Remarkably, most of these rapidly expanding settlements, often termed ‘urban sprawl’, are not built to cope well with apparent and increasing summer heat. Houses occupy most of the relatively small blocks, leaving little space for planting of green infrastructure or air circulation between buildings. In addition, they are often constructed using materials that accelerate local heat, including extensive use of dark roofs and dark bricks and no eaves to shade the single-glazed windows (Mellick Lopes et al. 2016).

Figure 4.1:The transformation of the suburb of Jordan Springs in the LGA of Penrith. The left image depicts a pastural landscape in 2012, which is transformed to typical urban sprawl by 2018. The high percentage of houses with dark roof materials is visible. Image © Nearmap.

Carparking Area While the area covered by carparks generally increased, the reverse was observed for some suburbs. Actually, one suburb in the LGA of Campbelltown City and 8 suburbs in the LGA of Parramatta City showed an exceptional decline in provision of carparks. The largest area of carparking space was observed in Wentworth Point (LGA of Parramatta City) where 45% of all carparking area was converted to high-density housing to accommodate a population

59 increase of more than 150% (Figure 4.2). On the other end of changes in space provided for parking are of course those suburbs where large conversion of greenfield takes place. For example, in the suburb of Marsden park, part of the LGA of Blacktown, the number of carparks increased from 1 to 30 (or from 0.3 ha to 14.6 ha) between 2010 and 2019.

Figure 4.2: An example for the decrease in carpark space at Wentworth Point, a suburb in the south-east of the LGA of Parramatta City. The left image shows a carpark with trees in 2010, while the right image shows the same area in 2019, now covered with high-density, multi-level housing estates. Image © Nearmap.

Multistorey above- and below-ground carparks deliver several advantages such as utilization of space or comfort and security for drivers. In addition, they provide ease-of-mind for car users that experience stress when struggling to find available, yet often very limited on-street parking, which also reduces pressure on traffic management systems in urban centres. Among the studied LGAs in western Sydney, most above-ground multistorey carparks were recorded in Parramatta and Cumberland. Notably, both densely populated areas had the highest carpark area to suburb area ratios. However, integration of multilevel carparks can lead to negative side effects. For example, they can negatively impact the living comfort of residents through declining air quality and increased noise. In a study by Hien and Foo (2003) it was reported that harmful emissions from motor vehicles resulted in an increased exposure to gaseous pollutants in flats close to a multilevel carpark.

Carpark and Population Change The problem to find a parking space in urban areas, especially in medium- and high-density residential precincts can be a problem. This issue increases further if local populations grow and general car dependency is high. The relationship between using a car and the availability 60 of carparking space at the end destination has been documented (Inci 2015). This relationship generally results in more parking space with increasing size of local populations and matches the results of the present study. Usually, the use of cars is low in dense city centres and business districts, and it is high in small and medium-sized urban areas where a combination of employment, amenities like cafes and restaurants, shops and other services are provided (Christiansen et al. 2017).

The relationships between the use of a car and a number of dependant variables that lead to a change in the use of a car have been studied in a landmark publication by Newman and Kenworthy (1989) entitled “Cities and Automobile Dependence”. The authors showed that per capita use of fuel has in inverse relationship with urban density (Figure 4.3). This seems logical, as higher population density often results in improved access to public transport. However, Newman and Kenworthy have been criticised for disregarding other variables that affect the consumption of fuel, particularly average household income (Dujardin et al. 2012; Perumal & Timmons 2017). Thus, the distance of individual’s homes to their place of employment and means like availability of public transport and income might influence the use of cars more than simply the density of citizens per square kilometre urban space. This complex relationship between car use and urban density may in fact be influenced by personal preference for travel, per-capita income, fuel price, the availability of highways, traffic congestion, and even differences in local cultures (Ewing et al. 2018). Certainly, population characteristics such as age and gender but also social norms, values and lifestyles will influence personal travel behaviour (Christiansen et al. 2017).

Figure 4.3: Relationship between urban population density and fuel use per capita for large metropolitan centres around the world. Source: Newman & Kenworthy (1989).

Across LGAs, and regardless of time, this study found a highly significant and positive relationship between the size of local populations and the area of carparking space provided. However, once assessed on a suburb scale, the strength of this relationship weakens considerably. This finding provides further evidence for the importance of the configuration of more local urban space, where the amount of available jobs, shops and other criteria dictate local travel behaviour (Næss 2012). Moreover, a meta-analysis showed that population density and job density were less well related once other variables were controlled (Ewing and Cervero 2010). However, based on these findings, it should not be concluded that population density contributes only marginally to overall vehicular traffic. Population density, local or regional, will add to the entire composition of cities, and high population density at the neighbourhood

62 scale is the trigger for the growing number of local facilities which subsequently leads to a reduction of local car traffic as destinations can be reached by walking. In addition, high population density enables more frequent public transport services along with shorter walking distances to bus stops or train stations.

A Way Forward It is well known that the development of urban space increases regional heat. This is owed to the transformation of green to grey infrastructure and increasing emissions of anthropogenic heat from energy use and traffic (Hwang, Lin & Huang 2017). The present study has identified asphalt as main surface material and concrete to a lesser extent in all six LGAs of western Sydney. More than 90% of all carparks were constructed with this material. This observation matches those made in other cities around the world (e.g., Fwa 1987; Pramesti, Molenaar and van de Ven 2012). The thermal properties of asphalt and concrete strongly influence the UHIE in the cities (Mohajerani, Bakaric & Jeffrey-Bailey 2017), which is mostly due to their omnipresence, and their thermal characteristics and surface albedo that allow storage and emission of high proportions of solar energy (Li 2015). Studies that assess surface temperatures of urban materials regularly identify markedly higher surface temperatures on asphalt compared to those of concrete (e.g., Takebayashi and Moriyama 2009, 2012; Di Maria et al. 2013).

These high surface temperatures documented on asphalt can be mitigated, although the best technical solution to reduce UHIE is yet to be determined (Mohajerani, Bakaric & Jeffrey- Bailey 2017). A range of strategies to reduce UHIE have been described in the Introduction of this thesis. Sadly, none of these mitigation strategies were used at scale in any of the six LGAs assessed here. One effective mechanism to cool urban space is the use of cool pavements. These materials have a high albedo and are permeable, porous and have even the capacity to store water within their mass (Santamouris 2013; Rossi et al. 2014). The higher reflectiveness of cool paving materials is achieved by changing their surface roughness or their colour, or both (Santamouris 2013). Materials with a smoother surface and/or a lighter colour will have a higher albedo which results in lower absorbance of solar radiation (Doulos, Santamouris & Livada 2004). Painting black asphalt with a reflective surface sealant will reduce surface temperatures by more than 4 °C (Di Maria et al. 2013) and is more effective in cooling than painting concrete.

Currently three LGAs in western Sydney (City of Parramatta, Campbelltown City and Blacktown) are testing the effectiveness of Cool Seal, a reflective surface coat, to reduce the surface temperature of asphalt. The Western Sydney Cool Roads Trial (see https://www.cityofparramatta.nsw.gov.au/western-sydney-cool-roads-trial) was implemented to test if coating roads and carparks will result in noticeable mitigation of surface heat and will lead to lower air temperatures in summer. Initial results of these trials indicate that Cool Seal can reduce the surface temperature of black asphalt by 8-10 °C. Other surface coat products have been tested in the United States (Figure 4.4) to define optimal colours and reflectiveness. The City of Los Angeles recently announced its Cool Streets LA program, that combines a range of cooling strategies that help mitigate the UHIE, including cool pavements, additional tree plantings, implementation of cool roof technology, construction of shade structures at bus stops and increasing access to drinking water through public water fountains (https://www.lamayor.org/mayor-garcetti-kicks-‘cool-streets-la’). Comprehensive programs like Cool Streets LA will indeed help to reduce the impact of summer heat, particularly on the most vulnerable communities and members of the public. Such programs are currently absent in western Sydney and their effectiveness to mitigate the UHIE is yet to be evaluated.

Figure 4.4: Berkeley Lab researchers measuring cool pavement technology to mitigate the negative effects of UHIE. Image source: Chao 2012.

Not only can cooling be provided by increasing albedo of a surface, but water retentive and evaporative pavements have been studied and reported to be effective mitigation measures to reduce UHIE (Nakayama & Hashimoto 2011). In Australia, the installation of permeable pavement systems and also techniques that collaboratively fall under the term of Water- sensitive Urban Design (WSUD) are in their infancy and are yet to be rolled out at scale in metropolitan centres across the country (Beecham, Pezzaniti & Kandasamy 2012). Permeable pavements have a porous upper layer that diverts rainwater towards channels where it can seep into the ground, whereas pervious pavement materials will allow rainwater to pass directly through the structure (Qin 2015). Many different products to create pervious or permeable carpark surfaces, including a wide range of pavers but also permeable concrete and asphalt (Figure 4.5). A small number of carparks in NSW have been constructed using porous concrete pavers and it was found that maintaining the visual appeal of these carparks was relatively simple (Beecham et al. 2009). In western Sydney, a number of carparks with permeable surfaces do exist. For example, the Western Sydney Parklands Trust has constructed the carparks at Bungarribee Park from locally sourced crushed sandstone. While pervious concrete paving materials are generally perceived as highly feasible for hot and car-dependent communities like those across western Sydney (Sartipi 2019), none of the 2250 carparks assessed here were constructed using these products.

Figure 4.5: Example of porous parking surface materials. Left: A paver called Grasscrete. Right: Porous asphalt. Source: www.grasscrete.com and www.civilogistix.com.

4.2 Consequences of Missing Shade in Carparks

It has been widely accepted that grey infrastructure is the primary source of UHIE (Priyadarsini 2009) and that increasing canopy and vegetation cover are important strategies that can help reducing the effect of UHIE and improve thermal comfort of local communities (Bowler et al.

2010). It has been estimated that with every 10% increase of vegetation cover, the surface temperature during summer days could be reduced by approximately 1 ℃ (Coutts & Harris 2013). The cooling effect of vegetation in summer has been documented in many studies (e.g., Srivanit and Hokao 2013; Yang, Lau and Qian 2011). However, green ground cover has only a marginal effect on air temperature compared to tree canopies that provide surface cooling through shading in addition to evaporative cooling from transpiration of water. Certainly, combining ground vegetation with tree cover will result in the most beneficial effect on local microclimate (Lin et al. 2017). Implementing an effective greening strategy is particularly important in new green field developments like those across western Sydney, where previously pastoral and agricultural land is converted to residential housing, roads and other hard infrastructure with very little shade. In such rapidly transforming car-focused landscapes, it becomes especially important to identify effective strategies that help reduce heat.

The research by Barİs, Sahİn and Yazgan (2009) has indicated that urban air temperature has a more direct link to the volume of vegetation, rather than the size of the vegetated area. This finding underlines the importance of large canopy trees, especially in carparks that are deprived of any green infrastructure. While planning policies in numerous countries provide clear guidance on compulsory implementation of fixed green-cover ratios, tree-cover ratios, and lawn-cover ratios (Wong et al. 2011), the Australian standard for parking facilities AS/NZS 2890.1:2004 does not include any such ratios. This important guideline for the construction of carparks only mentions trees once in paragraph 4.8 ‘Landscaping’ where their planting “is to be encouraged”. Algorithms for optimal placement of trees in carparks are readily available (Bajšanski et al. 2016). Yet, the lack of clear planning guidelines from local or state government agencies that mandate shade trees in carparks has resulted in the most alarming finding of the present research: while the area of carparks in western Sydney has increased by 1 km2 in the past decade, the canopy area of trees that shade this black space was insignificant.

Only 30% of carparks in the six LGAs contained trees. If trees were present, the mean number of trees was between 6 and 10 and the overall largest canopy cover in a single carpark was 2,500 m2. It is acknowledged that the net number of trees in carparks had increased between 2010 and 2019. However, all these greening attempts remained unimportant as 99% of the entire area covered by carparks remained unshaded. Trees have been identified as a meaningful tool to mitigate the UHIE, but to deliver noticeable cooling in carparks will require at least

42% coverage by their canopies (Lin et al. 2017). None of the sites assessed here had a canopy cover anywhere close to this threshold.

Until a tree has reached maturity, the size of its crown will continuously increase. This effect was noticeable in carparks across Campbelltown where the canopy area increased more between 2010 and 2019 than the number of trees. The reverse was observed for the CBD of Blacktown and other suburbs where the number if trees in carparks increased, but the area shaded by these trees did not change. This observation can be explained by changes in canopy growth and crown expansion during the life of a tree, which for most species follows an asymptotic growth trajectory (McPherson 2001).

During midday and the early afternoon, the surface temperature below a tree canopy can be as much as 20 °C lower compared to the same unshaded surface material (Golden & Kaloush 2006; Takebayashi & Moriyama 2012). The impact of tree shade on air temperature is much lower and can range from 0.64 to 2.52 °C in a shaded compared to a sunlit open urban area (Lin & Lin 2010). The combined effect of markedly lower surface heat and slightly lower air temperatures in shaded areas in a carpark will certainly result in greater human thermal comfort. This effect was also demonstrated in this research project. At all four carparks, tree shade reduced surface temperatures of black asphalt by 15-20 °C, reduced air temperatures by up to 5 °C and lowered black globe temperature (as proxi for human thermal comfort) by 5- 10℃. Large temperature reductions in surface and black globe temperature have been known to originate from excluding direct solar radiation, which in turn prevents emission of heat from the shaded surface into the urban environment where it warms air temperatures (Akbari, Pomerantz & Taha 2001).

Trees deliver this positive effect on microclimates under their canopies, although the magnitude of this cooling effect may differ among species. Pfautsch and Rouillard (2019) documented that large canopies of Queensland weeping figs produced a cooler microclimate compared to nearby eucalypt trees that had narrower and more open canopies. Another reason for differences among tree species and their cooling capacity is the variation of transpiration rates among species and canopy size (Jim & Tsang 2011; Pataki et al. 2011). Trees with higher transpiration rates will have a higher effect on latent heat flux and thus are more effective in cooling the surrounding air. However, Erell et al. (2010) has argued that the effect of trees on air temperature reduction right under tree may be overestimated and that any ‘feels like’ 67 temperature measured below trees is a much better indicator for the effectiveness of cooling provided by tree canopies. Reason for the larger effect on ‘feels like’ temperature compared to air temperature is the reduced exposed to sunrays that results in a much lower radiative flux (Mahmoud 2011), while local turbulence mixes large amounts of warm with small amounts of cooler air within short distances.

4.3 The Future of Carparks

In today’s urban landscapes provision of parking space seems unavoidable. Aboveground and belowground multistorey carparks can help reduce the land use by carparks (Panchal 2014). Existing and any new flat carparks should use pervious and light-coloured surface materials. However, the most important strategy to reduce the impact of flat, asphalt-covered carparks on summer heat in western Sydney will be to dramatically expand tree canopy cover. Strategic selection of planting positions and tree species will help improving the human thermal comfort in these heat islets (Bajšanski et al. 2016; Milošević, Bajšanski & Savić 2017).

The miscalculation of space requirements at the planning stage of carparks can result in the imbalance between parking supply and demand. While oversupply will result in increased local heat, and loss of potential green space, undersupply will lead to higher parking tariffs and traffic congestion (Ibrahim 2017). The introduction of a congestion toll and parking fees has shown to shift travel behaviour and reduce the use of private cars (Albert & Mahalel 2006). Capping parking supply, improving the walkability of neighbourhoods, providing cycling lanes and better access to public transport are proven methods that reduce car use. Several European cities have reduced or removed off-street parking, improved public transport and even converted existing carparks to recreational areas. For example, parking numbers in central Zurich, Switzerland and Oslo, Norway were capped, and large surface carparks were converted to green parks (Garrick & McCahill 2012). Similar examples are rare in Greater Western Sydney (Figure 4.6)

(a) (b) (c)

4.4 Limitations of this Study

For this study, I have only analysed carparks that are visible and can be measured using Nearmap images. This means that all underground and multistorey carparks were not included, which resulted in an underestimation of actually available parking space in each of the studies LGAs. Including underground and multistorey carparks would also lead to changes in the relationship between the dynamics of carparks and local population growth. However, underground and multistorey carparks do not contribute to UHIE, and my research was especially interested in exploring the potential contribution of flat, black and unshaded carparks to this phenomenon. Another limitation of my study is the analysis of change in the carparking area only in relation to changes in population density. Therefore, my study does not permit and conclusions on how urban form, travel behaviour and access to public transport influences the provision of parking space.

The issue of carparks as contributors to UHIE is not very well researched and remains unaddressed in western Sydney. For this profound reason, I had to revert to reports and articles published around the topic. While the use of non-peer reviewed literature is an obvious weakness, it also highlights that more research like mine is urgently needed. As western Sydney continues to grow rapidly, this research would deliver the necessary evidence base to introduce legislation around the design of heat-smart carparks.

4.5 Impact Statement

This research has found that in 2019, carparks in six LGAs covered 5.8 km2 of land in western Sydney. This area is larger than 960 soccer fields, of which 950 are covered by black asphalt without any shade. Before this research, the extent of carparking space and the fact that only 1% of this space is shaded was unknown.

It produced the first evidence about the relationship between carparking space and population growth in western Sydney. This relationship indicates that more land will be converted to carparks while the population of western Sydney is growing. In the past decade alone, an additional 100 hectares of parking space, predominately provided as unshaded black asphalt has been added to the region. Knowing that this form of urban infrastructure contributes to UHIE and raises local air temperatures, it can be expected that a growing number of carparks will contribute substantially to summer heat in western Sydney.

Despite countless initiatives and strategies to develop western Sydney more sustainably and responsibly, this research has shown that no progress has been made in the past decade to improve the ways how carparks are constructed. Thus, this study can form the basis to formulate new legislation, standards and best-practice guidelines that prevent the continuation of contemporary, unsustainable practices when building carparks. The research presented here can be used by local governments to address the problem of increasing urban heat and inform the development of targeted greening programs for carparks.

5 Conclusion

This research has shown that carparking space in western Sydney is expanding synchronously with population growth. As a result of high car dependency in the region, provision of this space seems unavoidable. The present work has also shown how effective tree shade can be to cool down carpark surfaces and improve human thermal comfort. This knowledge must be used by urban planners, landscape architects and developers when designing new infrastructure for the region, which already experiences extreme heat every summer. The largely unshaded space of several square kilometres of black asphalt is likely to contribute to this heat.

The region is experiencing rapid urbanisation and densification. This study demonstrated a positive relationship between the growth of local populations and the area used by carparks. Hence, continued population growth will lead to more carparks, which in turn will contribute to more summer heat. This vicious cycle and its predictable effect must be broken. The comparison of carpark space and its green cover in 2010 and 2019 has shown that no improvements in designing and building heat-smart carparks have been made in the past decade. Many strategies to prevent carparks from becoming heat islets are available, including trees to provide shade, cool pavements, reflective surface sealants or solar panels. None of these strategies have been found at noteworthy scale in the 2250 carparks studied here.

More research on the impacts of carparks on microclimates and the effectiveness of different heat mitigation strategies is necessary. Currently this research is absent in western Sydney where local populations are growing fast, transforming the region from rural and peri-urban into metropolitan space. Large tracts of pervious land covered by vegetation has been and will be turned into impervious hard space. This transformation is affecting the climate of the entire region and thus requires concerted efforts to mitigate the negative effects of increasing heat. This is especially urgent as climate change is already resulting in more frequent and longer lasting heatwaves with hotter peak temperatures. Responsible urban design must address this issue to provide liveable environments.

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Supplementary Figures

Figure S1: Blacktown LGA with its delineated suburbs.

Figure S2: Campbelltown LGA with its delineated suburbs.

Figure S3: Camden LGA with its delineated suburbs.

Figure S4: Cumberland LGA with its delineated suburbs.

Figure 5: Parramatta LGA with its delineated suburbs.

Figure S6: Blacktown LGA with its delineated suburbs.