Establish green spaces and water bodies in urban areas for urban cooling effect

Urban cooling islands (UCI) such as green and water spaces are areas within the urban regions with cooler surface temperatures compared with their neighboring landscapes (Ca et al., 1998). (Cruz et al, 2019)
Climate Adaptation Effectiveness

The study has confirmed that Iloilo River and the adjacent fishponds aids in urban heat island effect (UHI) mitigation. Its cooling effect reduces as the distance from the water extent increases until it reaches the edge of its influence scale. Results of the study also show that the UCI effect varies both spatially and temporally, as evidenced by the differences in UCI indices calculated at various image dates and delineated regions. The scale of the UCI effect covers longer distances in agricultural areas while higher temperature differences and UCI intensity can be experienced in zones with high built-up density. Different factors such as wetland spatial characteristics, meteorological conditions, and surrounding area characteristics can affect the performance of water spaces as a UCI. Increasing the area of water spaces may not bring significant improvement in cooling effect. It is more efficient to have smaller water spaces distributed across the urban area instead of a one large water space. (Cruz et al. 2019, pp.155-156). Similarly, the study of Tan et al. (2021) showed that while cooling effect increases as the size of the water body increases, there is only a certain threshold limit to this. For example, in Nanning, China, the optimal water patch size is 0.31 ha. Beyond this point, there is minimal increase in the cooling effect. Furthermore, the cooling range of water patches was an average of 180, while the cooling intensity was an average of 0.88 ◦C (Tan et al., 2021). Peng et al. (2020) recorded a maximum cooling intensity of water bodies of 5.54 °C in Pearl River Delta urban agglomeration.

Climate Hazards

  • Rising Land Surface Temperature

Locations

  • Iloilo City, Iloilo, Region VI (Western Visayas)

Adaptation Sectors

  • Urban

CCET Instuments

  • Action Delivery

Target Group based on Vulnerability

Basic Sectors:
  • Individuals residing in urban areas

Evaluations

Economic / Financial Effectiveness
Mid

Calculating the economic value of cooling effects using urban footprints in Great Britain, showed that an average of 2.45 Million Euros productivity loss per year across 11 Cities was avoided (Jones et al., 2024). Green spaces and blue spaces (water bodies) demand space and production which can be costly but economic benefits from recreational and tourism uses are reasonably effective.

Technical Feasibility
Mid

Urban cooling effect can be maximized by creating small but numerous artificial water spaces that are evenly distributed and strategically placed within the city instead of creating large but few water bodies which is also more difficult to accomplish considering the rapid conversion of open spaces to residential and commercial infrastructures (Cruz et al. 2019, p.155). Adding green spaces also increases the cooling effect. Sun and Chen (2012) suggest optimizing landscape design by factoring in the water body’s area, geometry, location, and the surrounding built-up proportion.

Social Acceptability
Low

There is potential conflict between establishing small water bodies in urban areas that these areas are being used or are intended to be used for residential and commercial spaces. (Cruz et al. 2019)

Environmental Impact
High (+)

Increasing Urban Cooling Islands through green spaces and water bodies contributes to a decrease in urban land surface and ambient temperatures. The urban cooling effect decreases electricity demand, improves natural sinks of GHG, and minimizes pollution (Santamouris, 2014). Additionally, green and blue spaces such as parks, green roofs, lakes, and rivers provide benefits such as a reduction in noise pollution (Fletcher et al., 2022), reduction of flood risk (Berland et al., 2017), and improvement of urban water quality (Livesley et al., 2016).

Mitigation co-benefit

If water bodies will be created along with green spaces to increase cooling efficiency/effect, this can reduce GHG emission. Moreover, the cooling effect of these spaces can lessen the electricity and water consumption of urban dwellers.

Keywords

urban cooling, water bodies, green space

References

• Cruz, J.A., Santos, J.A., Garcia, J.J., Blanco, A., and Moscoso, A.D., (2019). Spatiotemporal analysis of the urban cooling island (UCI) effect of water spaces in a highly urbanized city: A case study of Iloilo River and Adjacent Wetlands. The The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, 42-4. pp.149-156. https://www.researchgate.net/publication/338132041_SPATIOTEMPORAL_ANALYSIS_OF_THE_URBAN_COOLING_ISLAND_UCI_EFFECT_OF_WATER_SPACES_IN_A_HIGHLY_URBANIZED_CITY_A_CASE_STUDY_OF_ILOILO_RIVER_AND_ADJACENT_WETLANDS
• Sun, R. and Chen, L. (2012). How can urban water bodies be designed for climate adaptation? Landscape and Urban Planning, 105, pp.27-33 https://linkinghub.elsevier.com/retrieve/pii/S0169204611003409
• Tan, X., Sun, X., Huang, C., Yuan, Y., and Hou, D. (2021). Comparison of cooling effect between green space and water body. Sustainable Cities and Society, 67, pp. 1-11 https://doi.org/10.1016/j.scs.2021.102711
• Pend, J., Liu, Q., Xu, Z., Lyu, D., Du, Y, Qiao, R., and Wu, J. (2020). How to effectively mitigate urban heat island effect? A perspective of waterbody patch size threshold. Landscape and Urban Planning, 202 https://doi.org/10.1016/j.landurbplan.2020.103873
• Santamouris, M. (2014).Cooling the cities – A review of reflective and green roof mitigation technologies to fight heat islands and improve comfort in urban environments. Solar Energy. ISSN 0038-092X https://doi.org/10.1016/j.solener.2012.07.003.
• Fletcher, B.R. Damery, S. Aiyegbusi, O. L. Anderson, N. Calvert, M. Cockwell, P. Ferguson, J. Horton, M. Paap, Muirne, C.S. Sidey-Gibbons, C. (2022).Symptom burden and health-related quality of life in chronic kidney disease. University of Groningen https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1003954
• Berland, A. Shiflett, S.A. Shuster, W.D. Garmestani, A. Goddard, H. Hopton, M. (2017). The role of trees in urban stormwater management. Landscape and Urban Planning. https://doi.org/10.1016/j.landurbplan.2017.02.01.
• Livesley, S.J. McPherson, E.G. Calfapietra C. (2016). The Urban Forest and Ecosystem Services: Impacts on Urban Water, Heat, and Pollution Cycles at the Tree, Street, and City Scale. Journal of Environmental Quality. Volume 45. https://doi.org/10.2134/jeq2015.11.0567

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