Cooler Cities, Greener Spaces: Strategies for Sustainable Site Selection and Design

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Dive into the transformative world of sustainable site planning, where every choice echoes through ecosystems, energy efficiency, and community well-being. From choosing sites wisely to battling the urban heat island effect, discover how strategic planning can craft resilient, aesthetically pleasing, and ecologically sound urban environments.

Introduction

Sustainable site planning is no longer just a buzzword in the construction and urban planning industries. It has become a crucial aspect of creating and maintaining urban environments that are aesthetically pleasing, resilient, and ecologically sound. With rapid urbanization and the increasing challenges posed by climate change, there is a growing need for sustainable site planning and design in urban environments.

In fact, Goal 11 of the Sustainable Development Goals emphasises building sustainable cities wherein the environmental footprint is reduced by developing and enlarging the green infrastructure [1]. As cities continue to grow and evolve, the adoption of sustainable site design principles becomes increasingly essential to ensure the well-being of both present and future generations. 

Sustainable site planning integrates eco-conscious site selection, thoughtful site design, and effective stormwater management to create harmonious, resilient, and environmentally friendly urban environments. This blog explores the sustainable site selection criteria to minimise ecological damage to existing ecosystems and wildlife habitats. It further delves into sustainable site design principles, offering insights into strategies for both greenfield and urban site scenarios. The discourse expands to address the urban heat island effect--a phenomenon impacting temperatures in urban areas--and underscores the pivotal role of sustainable site design in mitigating this challenge.

The discussion on sustainable site planning through stormwater management strategies is provided in a different blog post: "Sustainable Stormwater Management: Minimising Urban Runoff Impact."

8 Key Reasons for Sustainable Site Planning

Sustainable site planning provides a comprehensive method for urban development, considering environmental, economic, and social factors. It is essential for several compelling reasons:

1. Ecosystem preservation: Avoiding development in sensitive areas protects critical ecosystems, preserves biodiversity, and maintains the delicate balance of natural habitats.
2. Resource efficiency: By selecting sites with minimal environmental impact, sustainable planning reduces the consumption of water, soil, and energy, contributing to overall resource efficiency.
3. Pollution prevention: Careful site selection minimises the risk of water pollution, ensuring water bodies remain uncontaminated and safeguarding the health of aquatic and terrestrial ecosystems.
4. Climate change mitigation: Sustainable planning addresses the carbon footprint associated with transportation and building energy consumption, aligning with global efforts to combat climate change. 
5. Urban heat island reduction: Implementation of green spaces and heat-reflective materials help mitigate the urban heat island effect, improving urban comfort and reducing energy use for cooling. 
6. Effective stormwater management: Sustainable planning strategies, such as avoiding excessive impervious surfaces and incorporating green infrastructure, controlling stormwater runoff, preventing soil erosion, and minimising flooding risks.
7. Conservation of undeveloped land: Prioritising redevelopment over opening new greenfield sites revitalises existing spaces and conserves valuable undeveloped land, preventing urban sprawl.
8. Promotion of sustainable urban living: Encouraging development in urban areas with existing infrastructure promotes higher densities, walkability, and reduced dependence on vehicles, contributing to a more sustainable and livable urban environment. 

Sustainable Site Selection

Choosing the right site to develop is a crucial first step in sustainable site design. Some of the key criteria to consider when selecting sustainable sites include:

Avoid environmentally sensitive areas

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Steering development away from areas with high ecological value or environmentally sensitive helps preserve critical ecosystems, safeguard biodiversity, and maintain the delicate balance of natural habitats [2]. For example, do not develop buildings, hardscapes, roads or parking areas on sites that are located in wetlands or protected forest areas, as these areas provide important ecological services and should be preserved. 

Prime agricultural land should also be avoided to minimise the impact on arable farming and preserve food production capabilities. Floodplain areas should also be avoided to mitigate the risk of flooding and potential damage to buildings. 

Public parkland and recreational areas should also be safeguarded, as these spaces provide essential community benefits and contribute to the overall well-being of residents. Sites close to water bodies should be carefully chosen to minimise the risk of water pollution and protect the health of nearby ecosystems. 

Prioritize redevelopment of damaged or used sites

For the sake of sustainability, choose previously developed locations to avoid sprawling development into the suburbs where greenfield sites would then be disturbed. Aim to redevelop and rehabilitate existing damaged or used sites such as brownfield and greyfield sites to reduce pressure on opening up new greenfield sites. 

Brownfield sites are damaged or contaminated sites containing hazardous substances, pollutants or contaminants that may require remediation before redevelopment. In comparison, greyfield sites are underused or abandoned sites with the potential for redevelopment. 

Greyfield site. Source: linux87/elements.envato.com

These sites often already have existing infrastructure in place, reducing the need for new construction and minimising resource consumption. Brownfield and greyfield sites are particularly beneficial to prioritise as they can be revitalized and repurposed, reducing the need for urban expansion and conserving valuable undeveloped land for other purposes.

Channel development to urban areas

Channel development to urban areas and existing urban fabric whenever possible to take advantage of existing infrastructure, transportation networks, and utilities. These areas are already developed and can support higher densities, reducing the need for sprawling development. 

Building in a high-density community promotes walkability and decreases dependence on vehicles. Additionally, select sites with access to public transportation and prioritizing transit-oriented development can further reduce dependence on personal vehicles and decrease carbon emissions.

Maximise community connectivity by building within 1 km of a residential neighbourhood to give an option for building occupants to live nearby. Prefer sites with access to various basic services (e.g. banks, shops, grocery stores, public parks, restaurants, clinics, etc.) that are available within a 1 km radius of the proposed building entrance. 

Design clear pathways and pedestrian-friendly spaces within the site leading to these basic services. This will encourage residents to utilise these services within walking or biking distance, reducing the need for vehicular transportation. 

In summary, the selection of sustainable sites has triple-bottom-line values. From the environmental perspective, choosing sustainable sites would avoid the destruction of wildlife habitats and help lessen the threat to their ability to survive. Consequently. we help protect the natural environment for future generations to enjoy and observe. Economically speaking, when we avoid sprawl development, we help lessen the burden of expanding infrastructure for both transportation and utilities, resulting in cost savings for taxpayers. 

Sustainable Site Design

When greenfield site is unavoidable

Designing sustainable sites requires careful consideration of specific criteria to ensure that development respects the Earth's bio-physical limits. When building on a greenfield site is unavoidable (such as building a forest management research centre, a wetland research and education centre or an eco-resort), following sustainable site design principles to minimise negative impacts and maximise positive outcomes is essential.

These principles include limiting the development footprint (total area of the building footprint, hardscape, access road and parking) by limiting site disturbance with setbacks to limit compaction in the construction area. Consider not to disrupt anything beyond 12 metres from the building perimeters and 3 metres from the hardscape, such as walkways, parking and patio [3]. Additionally, designing compact, efficient building layouts, and preserving as much existing vegetation as possible will help maintain the site's biodiversity and ecosystem services. 

One good example of a project with a minimal development footprint is the Seed Pod-shaped Treehouses at New Mandai Eco Resort in Singapore. Designed by a team of architects and environmental consultants, these treehouses were built on stilts to minimise disturbances to the forest floor and create an elevated living experience. 

Another excellent example is Green Village in Bali, where the designer chose to build up and not out. Like an inverted pyramid, the tapered bamboo form maximises land-use efficiency and preserves green space while providing a sustainable and luxurious tropical living environment. 

When a previously developed urban site is chosen

When a previously developed urban site is chosen for development, sustainable site design strategies become even more crucial. This type of site is normally covered with very impervious surfaces, considered environmentally damaged, and does not provide any natural habitat. Therefore, implementing sustainable site design strategies becomes essential to restore the ecological balance and create a greener and more resilient urban environment. 

In these cases, the sustainable site design principles would involve remediation and rehabilitation of the site by restoring at least half of the site area (not including the building footprint) with native vegetation to promote biodiversity and ecosystem function. Another strategy is to maximise open space and incorporate green infrastructure, such as rain gardens and bioswales, to manage stormwater runoff and improve water quality. More of this here: "Sustainable Stormwater Management: Minimising Urban Runoff Impact."

Mapletree Business City II in Singapore is an excellent example of a previously developed urban site that has successfully implemented sustainable site design strategies. The site was transformed from a former oil storage facility into a green and sustainable business hub. The design incorporated extensive green roofs, vertical gardens, and landscaped courtyards to maximise green space and promote biodiversity. By integrating these sustainable site design strategies, Mapletree Business City II not only minimised its ecological footprint but also created a healthier and more vibrant urban environment for its occupants. 

Understanding the urban heat island effect

The urban heat island (UHI) effect is a phenomenon where urban areas experience significantly higher temperatures compared to their rural surroundings [4]. The temperature difference is usually larger at night than during the day and is most apparent when winds are weak.

This is primarily caused by the abundance of concrete, asphalt, and other heat-absorbing materials that replace natural vegetation and water bodies, leading to increased heat retention during the day and heat release at night. The lack of greeneries in cities that promote evapotranspiration, shade, and schooling exacerbates the UHI effect. 

Furthermore, the heat in the city is released from vehicles and air-conditioners. Because the microclimate of the city is very hot, more energy is consumed for cooling, further contributing to the UHI effect [5].

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To mitigate the UHI effect and create cooler, more comfortable urban environments, it is crucial to incorporate sustainable site design strategies that prioritise the integration of green infrastructure into urban areas. Integrating green spaces, urban landscape optimisation, green roof construction, and sustainable site design can help reduce the heat retention caused by the abundance of heat-absorbing materials in urban areas.

For example, green spaces within urban areas provide a natural cooling effect by reducing surface temperatures and offering shade, thus mitigating the UHI effect. Additionally, the presence of vegetation helps improve air quality by absorbing pollutants and releasing oxygen, creating a healthier urban environment for residents. Green spaces can be on the roof of buildings, in the form of green roofs, or at ground level as parks, gardens, and landscaped areas.

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In Singapore, green roofs have been widely implemented, and the buildings not only contribute to a more aesthetically pleasing cityscape but also help reduce temperatures and improve air quality, contributing to a more sustainable and resilient urban environment.

Using high-albedo paving and roof material, which involves using materials with light-coloured and high solar reflectance, is another effective strategy for mitigating heat buildup in urban areas. These surfaces reflect a higher percentage of sunlight, reducing the amount of heat absorbed and ultimately decreasing the overall temperature in urban areas.

When designing parking spaces, aim to provide ample shading through the use of structures like carports covered with solar panels or shade trees to reduce the exposure of hard ground surfaces and vehicles to direct sunlight. Tuck-under parking also plays a significant role in reducing heat buildup in urban areas. Tuck-under parking helps reduce the amount of heat-absorbing surfaces exposed to direct sunlight by providing shaded and covered parking spaces. This not only contributes to lowering surface temperatures but also minimises the heat island effect in urban environments. 

Covered parking area. Source: Great_bru/elements.envato.com

Tuck-under parking. Source: Sandsun/elements.envato.com

Conclusion 

In conclusion, the implementation of green infrastructure, such as green roofs, green spaces, and high-albedo paving, plays a crucial role in mitigating the UHI effect and improving the livability and quality of urban environments. It is evident that integrating sustainable site design strategies, including the incorporation of green infrastructure and urban landscape optimisation, can significantly reduce heat retention and contribute to creating a healthier and more resilient urban environment.

With the incorporation of greenery in urban areas, there are numerous benefits, such as reducing air temperatures, improving outdoor thermal comfort, saving energy for space cooling, lowering greenhouse gas emissions, and enhancing urban space livability. Additionally, green infrastructure helps to reduce stormwater runoff, improve air quality, provide habitat for wildlife, and create aesthetically pleasing and socially beneficial urban environments. Overall, designing sustainable sites is crucial for creating greener and more resilient urban environments. 

Continue reading: "Sustainable Stormwater Management: Minimising Urban Runoff Impact."

References

[1] Mersal, A. (2016). Sustainable urban futures: Environmental planning for sustainable urban development. Procedia Environmental Sciences, 34, 49-61. 

[2] Li, Z., Ma, Z., & Zhou, G. (2022). Impact of land use change on habitat quality and regional biodiversity capacity: Temporal and spatial evolution and prediction analysis. Frontiers in Environmental Science, 10. 

[3] Dietz, M. E. (2007). Low impact development practices: A Review of current research and recommendations for future directions. Water, Air & Soil Pollution, 186, 351-363.

[4] Gago, E. J., Roldan, J. Pacheco-Torres, R. & Ordonez, J. (2013). The city and urban heat islands: A review of strategies to mitigate adverse effects. Renewable and Sustainable Energy Reviews, 25, 749-758.

[5] Taha, H. (2004). Urban heat island effect - an overview. In Cleveland, C. J. (Ed), Encylopedia of Energy. Elsevier Inc.