Urban blue-green space

Urban blue-green spaces can refer to any vegetated (green) areas and water bodies (blue) in a city environment. Cities that integrate urban blue-green space can be better adapted to climate change, while enhancing biodiversity and human well-being (Ebi & Bowen, 2023). These spaces create numerous social benefits and ecosystem services including improved aesthetic value, relaxation and wellbeing, climate regulation and reduction of urban heat island effect, disturbance prevention, purification, particularly of water and air, and provision of habitat for urban biodiversity.

Urban blue green spaces can vary in scale, from a building or street level (such as individual street trees or building green roofs), a neighbourhood scale (such as constructed wetlands), to large scale, city or region wide projects (such as river riparian or coastal restoration projects).

Specific examples of green space relevant to Moananui Oceania include:
Specific examples of blue space include:

Name of NbS

Urban blue-green space

Type of NbS

Created or constructed living ecosystems

Location

Urban

Urban blue-green spaces are a nature-based solution involving vegetation and water in urban areas. They take place generally as public-space projects, and as an overarching concept encompassing a range of specific examples, can occur almost anywhere in an urban environment – on streets, in parks, riparian areas, and on both coastal and rural edges. Some consider any contribution to urban vegetation and water in urban areas relevant, so the concept can also extend to include privately owned land (Ebi & Bowen, 2023; Wang et al., 2023).

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Case Study

Urban Forestry project in Port Vila

Department of Forestry tree nursery, Tagabe station, Port Vila. Photo from SPREP

Relationship to Indigenous knowledge

The concept of urban blue-green spaces can be supported by incorporating relevant indigenous knowledge. Indigenous knowledge systems in Te Moananui Oceania often embody holistic environmental relationships and approaches to stewardship (Granderson, 2017). Urban blue-green space can promote the interconnectedness of all elements of an ecosystem, by integrating natural environments into urban ones for the wellbeing of both humans and biodiversity. There are examples of how blue green space can enhance and protect knowledge relating to traditional foods and medicines (Potter et al., 2023). Development of urban blue-green space helps urban people to establishing a relationship with the natural world in urban landscapes, promoting the idea of reciprocity within nature that is also contained in many indigenous knowledge systems and worldviews globally (Ebi & Bowen, 2023; Granderson, 2017; Potter et al., 2023).

Climate change benefits
  • Biomass cover loss
  • Coastal inundation
  • Indirect health, social, cultural climate change impacts
  • Loss of food production
  • Loss of other ecosystem services
  • Reduced air quality
  • Reduced water quality
  • Urban heat island effect

Vegetation in urban blue-green space increases biomass cover in urban areas, especially in projects that create or emulate multi-layered ecosystems . Integrating vegetation in urban areas can improve air quality providing natural filtration. Likewise, blue features such as swales, raingardens and constructed wetlands work to slow the flow of runoff from urban areas, removing pollutants and sediment and improving water quality. There is clear evidence for the effect of vegetation in reduction of the urban heat island effect (Jiang et al., 2021; Qi et al., 2020).

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Societal / socio-cultural benefits
  • Biodiversity health and conservation
  • Climate change adaptation
  • Food security and quality
  • Human physical health and wellbeing

Urban blue green space can offer a range of societal benefits. Conservation of biodiversity is increasingly important in urban areas as Te Moananui Oceania rapidly urbanises, with associated reductions in vegetation cover (Hunter et al., 2023). Urban blue green space can provide habitat in city environments for various species, and help maintain diversity that is necessary for ecosystem adaption to climate change. Other ways that urban blue green space benefits climate change adaption include reduction of urban heat island effect thanks to vegetation in green space. Blue space equally helps manage water related climate change risks like increased stormwater and flooding (Jiang et al., 2021; Qi et al., 2020). In Te Moananui Oceania, sustaining traditional food systems like small-scale agroforestry alongside cultivation of native plants contribute to urban green space, while simultaneously improving access to local foods (Komugabe-Dixson et al., 2019). Often contributing to urban blue green infrastructure in cities, parks and open green space provide opportunity for physical activity, relaxation, and social interaction including cultural and community events.

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Ecological and biodiversity benefits
  • Aesthetic value/artistic inspiration
  • Climate regulation
  • Disturbance prevention
  • Food production (for humans)
  • Habitat provisionPurification (of water, soil, air)
  • Relaxation and psychological wellbeing

Aesthetic value is improved by blue-green spaces in urban areas, with classic examples being features like fountains and street trees. There is extensive research discussing the role of natural features in improved relaxation, psychological wellbeing, and health outcomes (Ebi & Bowen, 2023; Hunter et al., 2023; Potter et al., 2023). Climate regulation is improved in numerous ways, vegetation of all types works to shade and mitigate urban heat island effect, reduce heat sinking and larger open areas allow air movement in dense urban environments (Jiang et al., 2021). Water is urban environments is particularly effective at regulating climate, which alter humidity and temperature through evaporative cooling (Yu et al., 2020). Further, urban blue-green space can provide purification, especially of water through the use of features that slow and remove sediment and suspended pollutants, and plants which can filter and uptake pollution from water.

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Technical requirements

Unique environmental challenges and socio-cultural contexts in Oceania mean technical requirements are varied. Primarily, blue-green space projects require engagement from numerous stakeholders, including government and support from external organisations like NGOs. Government departments, particularly those with relationships to urban planning must collaborate, as urban blue-blue green projects often cover multiple sectors, such as water management, environmental conservation, and public space planning. Consideration of existing biodiversity must occur, including vegetation, soil quality, water sources.

Consideration of these factors allows design of spaces that mitigate climate change impacts like flooding or sea level rise, and are relevant to the specific land uses of the area. Specific infrastructure might be involved in the establishment or construction of blue-green space. For example nurseries are required to raise and stage seedlings for planting projects (Blaschke et al., 2017) In Te Moananui Oceania, planning and establishment of blue-green space should involve local communities, who already may contribute to blue-green space in the city through private activities. Equally often communities lead in the development of blue-green space projects and therefore deserve participatory consultation.

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Issues and Barriers

Informal urban development, and lack of planning in some cities of Te Moananui Oceania might form barriers to urban blue-green space that needs to be incorporated into planning of urban environments to ensure fair and adequate space is available, and to avoid displacement of people in the future (Granderson, 2017; Pedersen Zari et al., 2020). There can be significant policy and legal issues that impact the development and management of urban blue-green space in Te Moananui Oceania. An ongoing challenge is the integration of customary and indigenous local environmental management practices of land and resources with modern environmental law and standards.

Many Te Moananui Oceania communities operate in a way where customary law coexists with national and international policy (Vierros et al., 2010). This unique political and economic context can make enforcement of regulation difficult. Regulation is however important to ensuring blue green spaces are developed and maintained in a sustainable way. Land ownership tensions can hinder the establishment and expansion of blue-green space in Moananui Oceania, where often land is not just an economic asset to communities but holds spiritual, cultural, and communal significance (Kiddle et al., 2021). Communal nature of lander ownership or stewardship that is often practiced in Te Moananui Oceania can lead to tensions about how and where to allocate land for projects.

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Opportunities

There are numerous opportunities for utilisation of blue-green space (Blaschke et al., 2017; Jiang et al., 2021; Potter et al., 2023; Qi et al., 2020; Yu et al., 2020). Cities benefit when projects occur that simultaneously improve environmental outcomes while redeveloping key infrastructure, developing ways to reverse degradation in a meaningful way. Because of the scale of blue-green space projects, collaboration across governmental and community organisations and businesses is often required. Blue-green space projects can also generate opportunities in education and training of local people in design, establishment and maintenance (Blaschke et al., 2017). Tourism opportunities are developed by notable public projects or improvements to cityscapes, and businesses in project areas therefore also benefit from increased patronage. Numerous industries can be involved in establishing and maintaining blue-green projects, stimulating financial and industry development. In some cities, ecosystem connectivity can be improved by utilising blue-green space as biodiversity corridors through urban areas. This is especially important in pacific cities where informal development prevails.

Financial case

Clearly blue green spaces provide numerous benefits to climate change mitigation, socio-cultural and biodiversity. Blue green spaces generally are recognised for their providing of urban ecosystem services, which themselves can be represented as a qualitatively assessed monetary value, and considered part of the infrastructure of urban space (urban green infrastructure) like parks, wetlands and urban biodiversity. Because of the nature of blue green space, requiring financial value to be decided on in a qualitative manner, specific values for forming a financial case are difficult to obtain. The WHO Regional Office for Europe, (2023) released a helpful report on the value of blue-green space, which does provide some case studies with specific monetary figures.

In Te-Moananui Oceania, blue-green space often also often represents food, forgeable resources including building material, and fuel (Blaschke et al., 2017). These blue-green spaces become important sources of supplementary resource for housholds and communities.

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Waitangi park opening” CC BY-NC-SA 2.0 by Br3nda via Flickr
References
  • Blaschke, P. M., Pedersen Zari, M., Archie, K. M., Jackson, B., Komugabe-Dixson, A., Livesey, C., Loubser, D., Gual, C. M.-A., Maxwell, D., Rastandeh, A., Renwick, J., & Weaver, S. (2017). Ecosystem assessment and ecosystem-based adaptation (EbA) options for Port Vila, Vanuatu [Technical Report]. Victoria University of Wellington.
  • Ebi, K. L., & Bowen, K. (2023). Green and blue spaces: Crucial for healthy, sustainable urban futures. The Lancet, 401(10376), 529–530. https://doi.org/10.1016/S0140-6736(23)00096-X
  • Granderson, A. A. (2017). The role of traditional knowledge in building adaptive capacity for climate change: Perspectives from Vanuatu. Weather, Climate, and Society, 9(3), 545–561. https://doi.org/10.1175/WCAS-D-16-0094.1
  • Hunter, R. F., Nieuwenhuijsen, M., Fabian, C., Murphy, N., O’Hara, K., Rappe, E., Sallis, J. F., Lambert, E. V., Duenas, O. L. S., Sugiyama, T., & Kahlmeier, S. (2023). Advancing urban green and blue space contributions to public health. The Lancet Public Health, 8(9), e735–e742. https://doi.org/10.1016/S2468-2667(23)00156-1
  • Jiang, Y., Huang, J., Shi, T., & Wang, H. (2021). Interaction of urban rivers and green space morphology to mitigate the urban heat island effect: Case-based comparative analysis. International Journal of Environmental Research and Public Health, 18(21), 11404. https://doi.org/10.3390/ijerph182111404
  • Kiddle, G. L., Pedersen Zari, M., Blaschke, P., Chanse, V., & Kiddle, R. (2021). An Oceania urban design agenda linking ecosystem services, nature-based solutions, traditional ecological knowledge and wellbeing. Sustainability, 13(22), 12660. https://doi.org/10.3390/su132212660
  • Komugabe-Dixson, A. F., De Ville, N. S. E., Trundle, A., & McEvoy, D. (2019). Environmental change, urbanisation, and socio-ecological resilience in the Pacific: Community narratives from Port Vila, Vanuatu. Ecosystem Services, 39, 100973. https://doi.org/10.1016/j.ecoser.2019.100973
  • Pedersen Zari, M., Blaschke, P. M., Jackson, B., Komugabe-Dixson, A., Livesey, C., Loubser, D. I., Martinez-Almoyna Gual, C., Maxwell, D., Rastandeh, A., Renwick, J., Weaver, S., & Archie, K. M. (2020). Devising urban ecosystem-based adaptation (EbA) projects with developing nations: A case study of Port Vila, Vanuatu. Ocean & Coastal Management, 184, 105037. https://doi.org/10.1016/j.ocecoaman.2019.105037
  • Potter, J. D., Brooks, C., Donovan, G., Cunningham, C., & Douwes, J. (2023). A perspective on green, blue, and grey spaces, biodiversity, microbiota, and human health. Science of The Total Environment, 892, 164772. https://doi.org/10.1016/j.scitotenv.2023.164772
  • Qi, Y., Chan, F. K. S., Thorne, C., O’Donnell, E., Quagliolo, C., Comino, E., Pezzoli, A., Li, L., Griffiths, J., Sang, Y., & Feng, M. (2020). Addressing challenges of urban water management in Chinese sponge cities via Nature-Based Solutions. Water, 12(10), 2788. https://doi.org/10.3390/w12102788
  • Vierros, M., Tawake, A., Hickey, F., Tiraa, A., & Noa, R. (2010). Traditional marine management areas of the Pacific in the context of national and international law and policy. United Nations University – Traditional Knowledge Initiative.
  • Wang, X., Ouyang, L., Lin, J., An, P., Wang, W., Liu, L., & Wu, L. (2023). Spatial patterns of urban green-blue spaces and residents’ well-being: The mediating effect of neighborhood social cohesion. Land, 12(7), 1454. https://doi.org/10.3390/land12071454
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