Analysis of the Role of Sponge City Components in Enhancing Urban Resilience to Flood Hazards (Case Study: Zanjan City)
Subject Areas : Sustainable urban developmentHossein Tahmasebi Moghaddam 1 , Majid Hazraty 2
1 - Assistant Professor, Department of Geography, Faculty of Humanities, University of Zanjan, Zanjan, Iran.
2 - PhD Candidate in Geography and Urban Planning, Faculty of Humanities, University of Zanjan, Zanjan, Iran.
Keywords: Resilience, Sponge City, Hazards, Flood, Zanjan.,
Abstract :
Rapid urban development and the increase in impervious surfaces in Zanjan City, as in many other urban areas, have reduced resilience to flood hazards and placed significant strain on traditional drainage systems. Given the increasing trend of extreme weather events and their disproportionate impacts on vulnerable communities, purely engineering-based approaches are no longer sufficient to address the challenges posed by climate change. In this context, the principles of sponge cities—offering multifunctional environmental, ecological, social, and economic benefits—are considered effective tools for enhancing urban resilience against floods and other climate-related hazards.This article employs an analytical-exploratory method to examine the role of sponge city components in enhancing urban resilience to flood hazards in Zanjan City. Data collection was carried out through field surveys and library research. The statistical population was selected using a fuzzy Delphi analysis involving 30 urban planning experts from academic institutions. Data analysis was conducted using Structural Equation Modeling (SEM) and path analysis in SmartPLS software.The results indicate that the highest factor loadings among sponge city indicators are: rainwater infiltration into the ground (0.911), rainwater filtration (0.962), reduction of peak river flow (0.922), and preservation of natural hydrological processes (0.936). Regarding urban resilience, the highest factor loadings correspond to population at risk (0.979), ratio of large to small businesses (0.919), shelter capacity (0.979), and urban environmental health (0.974). Moreover, based on the structural equation model, green spaces, restoration of natural waterways, and permeable pavements have the most significant and positive impacts on urban resilience. Additionally, social and institutional-infrastructural resilience dimensions exhibit the highest levels of influence.
Extended Abstract
Introduction
Rapid urban development and the expansion of impervious surfaces—such as asphalt and concrete—have significantly reduced the land’s natural ability to absorb and store rainwater. This situation has increased surface runoff, overburdened traditional drainage systems, and elevated the risk of urban flooding. Additionally, urbanization has amplified the vulnerability of cities to climate change impacts. Zanjan city, like many others, suffers from traditional grey infrastructure that cannot sufficiently handle the growing frequency and intensity of extreme weather events. In this context, the concept of the “sponge city” has emerged as a multifunctional and resilient approach that manages rainwater through absorption, storage, filtration, and reuse. This study aims to identify the most effective sponge city components in enhancing Zanjan’s urban resilience against flood hazards.
Methodology
This research is applied in purpose and mixed in method, combining qualitative and quantitative approaches. In the qualitative phase, influential sponge city components were identified through literature review and a fuzzy Delphi method involving 30 urban planning experts. For sampling, availability and expertise criteria were considered. In the quantitative phase, the structural equation modeling (SEM) technique and path analysis were employed using SmartPLS software to evaluate causal relationships between components and urban resilience. The reliability of the instruments was confirmed by Cronbach’s alpha coefficients above 0.7. Across two Delphi rounds, 33 sponge city components were validated with fuzzy weights above the 0.7 threshold, and their impacts on social, economic, institutional-infrastructural, and environmental resilience were analyzed.
Results and discussion
Confirmatory factor analysis showed that components such as green spaces and natural stream restoration (impact coefficient = 0.556), permeable pavements (0.466), artificial wetlands and ponds (0.366), and biological retention systems (0.239) have the most significant positive and meaningful effects on urban resilience. Specifically, green infrastructure features—such as preserving hydrological processes, maintaining runoff, and providing recreational spaces—played a crucial role in resilience building.
Among urban resilience indicators, the most influential social variables were “population at risk” (0.979) and “family structure” (0.914). In the institutional-infrastructural domain, “shelter capacity” (0.979) and “arterial road network density” (0.949) had high factor loadings. Economic resilience was mainly influenced by “large-to-small business ratio” (0.919) and “access to reconstruction loans” (0.904), while environmental resilience was most affected by “urban environmental health” (0.974) and “public participation in sanitation” (0.962).
All path coefficients between sponge city components and urban resilience were positive and statistically significant (p < 0.05). Among the dimensions of resilience, social (β = 0.500) and institutional-infrastructural (β = 0.446) resilience were the most affected by sponge city elements.
Conclusion
This study confirms that integrating sponge city principles into urban planning provides an effective strategy for enhancing resilience against climate-related hazards, especially floods. Key findings indicate that expanding green infrastructure, restoring waterways, implementing permeable surfaces, and utilizing natural filtration systems significantly improve resilience. Furthermore, strengthening social and institutional dimensions—such as community awareness, education, family support systems, and emergency infrastructure—proves essential in urban adaptation. Policymakers are recommended to prioritize sponge city principles in development plans to support long-term climate resilience and sustainable water management. Emphasis on decentralized, eco-friendly solutions can complement large-scale infrastructure, reduce urban vulnerability, and improve overall livability, public health, and environmental sustainability.
Ahadnejad Reveshty, M., Tahmasebi Moghaddam, H., & Heydari, M. T. (2022). Analysis of factors affecting the enhancement of urban communities’ resilience against the COVID-19 pandemic with a community-centered crisis management approach: A case study of Zanjan city. Amayesh-e Mohit, 15(59), 159–186. https://dorl.net/dor/20.1001.1.2676783.1401.15.59.8.3. [in Persian].
Tahmasebi Moghaddam, H., Ahadnejad Reveshty, M., Heydari, M. T., & Shoghli, A. (2021). Explaining factors influencing social resilience against biological hazards with an emphasis on COVID-19: A case study of Zanjan city. Geography and Environmental Hazards, 10(1), 1–19. https://doi.org/ 10.22067/geoeh.2021.67234.0. [in Persian].
Malek Hosseini, O. (2020). Natural hazards in Iran. Roshd-e Amoozesh-e Joghrafia, 34(3). https://www.roshdmag.ir. [in Persian].
Adger, W. N., Hughes, T. P., Folke, C., Carpenter, S. R., & Rockstrom, J. (2005). Social-ecological resilience to coastal disasters. Science, 309(5737), 1036-1039. https://doi.org/10.1126/science.1112122
Aldrich, D. P., & Meyer, M. A. (2015). Social capital and community resilience. American behavioral scientist, 59(2), 254-269. https://doi.org/10.1177/0002764214550299
Annex II, I. P. C. C. (2022). Glossary [Möller, VR van Diemen, JBR Matthews, C. Méndez, S. Semenov, JS Fuglestvedt, A. Reisinger. Climate change, 2897-2930. https://www.ipcc.ch/report/ar6/wg2/downloads/report/IPCC_AR6_WGII_Annex-II.pdf
Asian Cities Climate Change Resilience Network. (2011). Surat City Resilience Strategy, The Rockefeller Foundation, Surat Municipal Corporation, The Southern Gujarat Chamber of Commerce and Industry, TARU Leading Edge.https://resiliencestrata.org/uploads/pdf/77D5DAE4-0403-4966-B646-809EF2C3E68A.pdf
Blunt, L. F. (2025). Selling the Sponge City: Copenhagen’s Strategy for Cloudburst Management. http://lup.lub.lu.se/student-papers/record/9193475
Chan, F. K. S., Griffiths, J. A., Higgitt, D., Xu, S., Zhu, F., Tang, Y. T., ... & Thorne, C. R. (2018). “Sponge City” in China—a breakthrough of planning and flood risk management in the urban context. Land use policy, 76, 772-778. http://dx.doi.org/10.1016/j.landusepol.2018.03.005
Citaristi, I. (2022). World Meteorological Organization—WMO. In The Europa Directory of International Organizations 2022 (pp. 399-404). Routledge.https://doi.org/10.4324/9781003292548
Cities Are Becoming More Like Sponges - Reasons to be Cheerful, accessed June 12, 2025, https://reasonstobecheerful.world/sponge-cities-china-climate-change-resilience/
Cutter, S. L., Burton, C. G., & Emrich, C. T. (2010). Disaster resilience indicators for benchmarking baseline conditions. Journal of homeland security and emergency management, 7(1). https://doi.org/10.2202/1547-7355.1732
Deng, Y., Deng, J., & Zhang, C. (2022). Sponge City and Water Environment Planning and Construction in Jibu District in Changde City. Sustainability, 15(1), 444.https://doi.org/10.3390/su15010444
Dresden (2024). Environmental protection. [online] www.dresden.de. Cited 24 May 2024. Available at: https://www.dresden.de/en/living/environment/Environmental Protection.php
Environmental Protection Agency. (2016). Climate Change Indicators: Weather and Climate. https://www.epa.gov/climate-indicators/weather-climate
European Environmental Agency. 2021. Water resources across Europe — confronting water stress: an updated assessment — European Environment Agency. [online] Cited 18 March 2024. Available at: https://www.eea.europa.eu/publications/water-resources across-europe-confronting.
Fletcher, T. D., Shuster, W., Hunt, W. F., Ashley, R., Butler, D., Arthur, S., & Viklander, M. (2015). SUDS, LID, BMPs, WSUD and more–The evolution and application of terminology surrounding urban drainage. Urban water journal, 12(7), 525-542. http://dx.doi.org/10.1080/1573062X.2014.916314
Guan, X., Wang, J. and Xiao, F. 2021. Sponge city strategy and application of pavement materials in sponge city. Journal of Cleaner Production, 303(303 (2021) 127022), p.127022. https://doi.org/10.1016/j.jclepro.2021.127022.
Hallegatte, S. (2014). Economic resilience: definition and measurement. World bank policy research working paper, (6852). https://ssrn.com/abstract=2432352
Hamidi, A., Ramavandi, B., & Sorial, G. A. (2021). Sponge City—An emerging concept in sustainable water resource management: A scientometric analysis. Resources, Environment and Sustainability, 5, 100028. http://dx.doi.org/10.1016/j.resenv.2021.100028
Helmreich, B. 2021. Rainwater Management in Urban Areas. Water, 13(8), p.1096. https://doi.org/10.3390/w13081096.
Hora, K. E. R., & Sales, M. M. (2019). For more sponge cities. In Planning Cities with Nature: Theories, Strategies and Methods (pp. 251-263). Cham: Springer International Publishing. https://doi.org/10.1007/978-3-030-01866-5
Imran, H. M., Akib, S., & Karim, M. R. (2013). Permeable pavement and stormwater management systems: a review. Environmental technology, 34(18), 2649-2656. https://doi.org/10.1080/09593330.2013.782573
Ix, F. M., & George, E. H. (2022). Review on sponge city construction for flood management. Sustainability, Agri, Food and Environmental Research, 10(1), 109-117. http://dx.doi.org/10.7770/safer-V10N1-art2537
Jardine, A., & Long, J. (2014). Synopsis of climate change. Gen. Tech. Rep. PSW-GTR-247. Albany, CA: US Department of Agriculture, Forest Service, Pacific Southwest Research Station: 71-81. Chap. 1.4, 247, 71-81.https://research.fs.usda.gov/treesearch/46955
Köster, S., Hadler, G., Opitz, L. and Thoms, A. 2023. Using Stormwater in a Sponge City as a New Wing of Urban Water Supply—A Case Study. Water, 15(10), p.1893. doi: Cited 1 May 2024. Available at: https://doi.org/10.3390/w15101893
Li, H., Ding, L., Ren, M., Li, C. and Wang, H. 2017. Sponge City Construction in China: A Survey of the Challenges and Opportunities. Water, 9(9), p.594. doi: Cited 8 March 2024. Available at: https://doi.org/10.3390/w9090594
Li, H., Ishidaira, H., Wei, Y., Souma, K., & Magome, J. (2022). Assessment of sponge city flood control capacity according to rainfall pattern using a numerical model after muti-Source validation. Water, 14(5), 769.https://doi.org/10.3390/w14050769
Li, L., Li, C., Wang, H., & Xu, F. (2024). Precondition Study of a Sponge City: Comprehensive Assessment of the Vulnerability of an Urban Rainwater System. Sustainability, 16(10), 3897.https://doi.org/10.3390/su16103897
Liang, C., Zhang, X., Xia, J., Xu, J., & She, D. (2020). The effect of sponge city construction for reducing directly connected impervious areas on hydrological responses at the urban catchment scale. Water, 12(4), 1163.https://doi.org/10.3390/w12041163
Liu, H., Jia, Y., & Niu, C. (2017). “Sponge city” concept helps solve China’s urban water problems. https://doi.org/10.1007/s12665-017-6652-3
Ma, J., Liu, D., & Wang, Z. (2023). Sponge city construction and urban economic sustainable development: an ecological philosophical perspective. International journal of environmental research and public health, 20(3), 1694. https://doi.org/10.3390/ijerph20031694
Network, A. C. C. C. R. (2013). ACCCRN city projects. Bangkok: Asian Cities Climate Change Resilience Network (ACCCRN).https://www.acccrn.net/
Nguyen, T. T., Ngo, H. H., Guo, W., Wang, X. C., Ren, N., Li, G., ... & Liang, H. (2019). Implementation of a specific urban water management-Sponge City. Science of the Total Environment, 652, 147-162.https://doi.org/10.1016/j.scitotenv.2018.10.168
Nguyen, T.T., Ngo, H.H., Guo, W. and Wang, X.C. 2020. A new model framework for sponge city implementation: Emerging challenges and future developments. Journal of Environmental Management, 253(253 (2020) 109689), p.109689. doi: Cited 22 June 2024. Available at: https://doi.org/10.1016/j.jenvman.2019.109689
Nguyen, T.T., Ngo, H.H., Guo, W., Wang, X.C., Ren, N., Li, G., Ding, J. and Liang, H. 2019. Implementation of a specific urban water management - Sponge City. Science of The Total Environment, 652(652 (2019) 147–162), pp.147–162. https://doi.org/10.1016/j.scitotenv.2018.10.168
Norris, F. H., Stevens, S. P., Pfefferbaum, B., Wyche, K. F., & Pfefferbaum, R. L. (2008). Community resilience as a metaphor, theory, set of capacities, and strategy for disaster readiness. American journal of community psychology, 41(1), 127-150. https://doi.org/10.1007/s10464-007-9156-6
One Click LCA. (2025, June 12). Optimize sponge cities for floods | ENVI-met. Retrieved from https://oneclicklca.com/en/resources/articles/microclimate-modeling-to-optimize-sponge-cities-for-flood-resilience
Optimize sponge cities for floods | ENVI-met from One Click LCA, accessed June 12, 2025, https://oneclicklca.com/en/resources/articles/microclimate-modeling-to-optimize-sponge-cities-for-flood-resilience
Optimize sponge cities for floods | ENVI-met from One Click LCA, accessed June 12, 2025, https://oneclicklca.com/en/resources/articles/microclimate-modeling-to-optimize-sponge-cities-for-flood-resilience
RamYar, M., & Shamsoddini, A. (2025). Future study of socio-economic indicators affecting the resilience of Region 6 of Shiraz metropolis in the face of flooding. Geography and Regional Future Studies, 3(2), 16-33. https://doi.org/10.30466/grfs.2025.55894.1085
Rose, A. (2007). Economic resilience to natural and man-made disasters: Multidisciplinary origins and contextual dimensions. Environmental hazards, 7(4), 383-398. https://doi.org/10.1016/j.envhaz.2007.10.001?scroll=top
Shahpari Sani, D., Heidari, M. T., Tahmasebi Mogaddam, H., Nadizadeh Shorabeh, S., Yousefvand, S., Karmpour, A., & Jokar Arsanjani, J. (2022). An assessment of social resilience against natural hazards through multi-criteria decision making in geographical setting: a case study of Sarpol-e Zahab, Iran. Sustainability, 14(14), 8304. https://doi.org/10.3390/su14148304
Sun, Y., Deng, L., Pan, S.-Y., Sable, S., & Shah, K. 2020. Integration of green and gray infrastructure for sponge city: water and energy nexus. Water-Energy Nexus, 3 (n.d), 29 30. https://doi.org/10.1016/j.wen.2020.03.003
Szeląg, B., Łagód, G., Musz-Pomorska, A., Widomski, M.K., Stránský, D., Sokáč, M., Pokrývková, J. and Babko, R. 2022. Development of Rainfall-Runoff Models for Sustainable Stormwater Management in Urbanized Catchments. Water, 14(13), p.1997. doi: Cited 14 July 2024. Available at: https://doi.org/10.3390/w14131997
Tahmasebi, H. , Heydari, M. T. , Vaezi, M. and Rasoulzade, Z. (2022). Explain The role of NGOs in increasing social resilience against the Corona pandemic(Case study: Tabriz city). Geographical Urban Planning Research (GUPR), 9(4), 1079-1102.[in persian] https://doi.org/10.22059/jurbangeo.2021.322716.151
Twyman, B. (2025). Sponge Cities: A Comparison of Urban Stormwater and Flood Management Programs in China and the United States (Master's thesis, Tufts University). https://www.scitepress.org/Papers/2024/133373/133373.pdf
Uzoqov, B. (2024). Application of Sponge City concept to address the issues of stormwater management in urban areas: Prohlis, Dresden. https://urn.fi/URN:NBN:fi:amk-2024091925364
Wang, J., Zhou, L., Han, P., & Li, G. (2020). The impact of urbanization and LID technology on hydrological effect. Journal of Coastal Research, 104(SI), 14-22. https://doi.org/10.2112/jcr-si104-004.1
What is a sponge city? - Internet Geography, accessed June 12, 2025, https://www.internetgeography.net/what-is-a-sponge-city/
Wu, Y. G. (2016). Sponge City Design: Concept, Technology & Case Study. Jiangsu. Phoenix Science Press. http://dx.doi.org/10.1061/9780784479858.031
Xia, J., Zhang, Y., Xiong, L., He, S., Wang, L., & Yu, Z. (2017). Opportunities and challenges of the Sponge City construction related to urban water issues in China. Science China Earth Sciences, 60, 652-658.http://dx.doi.org/10.1007/s11430-016-0111-8
Yang, D., Zhao, X. and Anderson, B.C. 2022. Integrating Sponge City Requirements into the Management of Urban Development Land: An Improved Methodology for Sponge City Implementation. Water, 14(7), p.1156. Cited 18 July 2024. Available at: https://doi.org/10.3390/w14071156
Yin, D., Chen, Y., Jia, H., Wang, Q., Chen, Z., Xu, C., Li, Q., Wang, W., Yang, Y., Fu, G. and Chen, A.S. 2021. Sponge city practice in China: A review of construction, assessment, operational and maintenance. Journal of Cleaner Production, 280(280 (2021) 124963), p.124963. Cited 04 July 2024. Available at: https://doi.org/10.1016/j.jclepro.2020.124963
Yu, K. (2015). “Sponge City”: Theory and Practice. City Planning Review. 39 (6): 26–36. Retrieved 2020-12-15.https://www.turenscape.com/topic/en/spongecity/index.html
Yu, K. (2017). Green infrastructure through the revival of ancient wisdom. Bulletin of the American Academy of Arts and Sciences, 70(4), 35-39.https://scispace.com/pdf/green-infrastructure-through-the-revival-of-ancient-wisdom-3mxzjhgfcv.pdf
Zevenbergen, C., Fu, D., & Pathirana, A. (2018). Transitioning to sponge cities: Challenges and opportunities to address urban water problems in China. Water, 10(9), 1230. https://doi.org/10.3390/w10091230
Zhao, L., Lee, X., Smith, R.B. and Oleson, K. 2014. Strong contributions of local background climate to urban heat islands. Nature, [online] 511(7508), pp.216–219. Cited 2 June 2024. Available at: https://doi.org/10.1038/nature13462
