Keywords
Abstract
Urban flooding is a growing challenge in rapidly urbanising coastal cities, where intense monsoon rainfall interacts with expanding impervious surfaces, shrinking wetlands, and inadequate drainage capacity. The Chennai Metropolitan Area (CMA) has experienced major flood events, notably in 2005, 2015, and 2023, highlighting the need to understand the spatial drivers of flood risk. This study uses a GIS-based approach to examine the relationship between urban growth and flood susceptibility across CMA. Multi-temporal Landsat imagery (2000, 2010, 2015, 2020, and 2024) was used to assess LULC and impervious surface changes, while SRTM DEM data supported Flow Accumulation and Topographic Wetness Index (TWI) analysis. Historical flood locations were analysed using Kernel Density Estimation (KDE) to identify flood hotspots. Built-up area increased from 321.87 km² in 2000 to 346.33 km² in 2024 within the approximately 436.5 km² study area. Rainfall analysis using IMD gridded data showed that the 2015 event (349.63 mm/day) exceeded the estimated 100-year return-period rainfall of 330.19 mm/day, while the 2023 event (243.97 mm/day) was approximately associated with a 25-year return period. The combined spatial analysis indicates that flood-prone areas are concentrated in low-lying coastal zones, western and southern peri-urban areas, and the Adyar River floodplain, where urban expansion, high flow accumulation, and historical flood occurrences overlap. The findings highlight the importance of integrating land-use planning, terrain characteristics, and historical flood information for improving urban flood-risk management in Chennai.
References
1. Bronstert, A., Niehoff, D., & Burger, G. (2002). Effects of climate and land-use change on storm runoff generation: Present knowledge and modelling capabilities. Hydrological Processes, 16(2), 509–529. https://doi.org/10.1002/hyp.326
2. Ertan, S., & Celik, R.N. (2021). The assessment of urbanisation effect and sustainable drainage solutions on flood hazard by GIS. Sustainability, 13(4), 2293. https://doi.org/10.3390/su13042293
3. Sharma, A., Poonia, M., Rai, A., Biniwale, R.B., Tiwari, A., Lachure, S., Tuegel, F., Holzbecher, E., & Hinkelmann, R. (2024). Impact of land use and rainfall change on runoff and flood resilience of an urban environment: A case study of Chennai City, India. Arabian Journal of Geosciences, 17(6), 208. https://doi.org/10.1007/s12517-024-11985-6
4. Bagyaraj, M., Senapathi, V., Chung, S.Y., Gopalakrishnan, G., Xiao, Y., Karthikeyan, S., Nadiri, A.A. and Barzegar, R. (2023) ‘A geospatial approach for assessing urban flood risk zones in Chennai, Tamil Nadu, India’, Environmental Science and Pollution Research, 30(45), pp. 100562–100575. doi:10.1007/s11356-023-29132-1.
5. Bremner, L. (2020). Planning the 2015 Chennai floods. Environment and Planning E: Nature and Space, 3(3), 732-760. https://doi.org/10.1177/2514848619880130
6. Burns, M.J., Fletcher, T.D., Walsh, C.J., Ladson, A.R. and Hatt, B.E. (2012) ‘Hydrologic shortcomings of conventional urban stormwater management and opportunities for reform’, Landscape and Urban Planning, 105(3), pp. 230–240. doi:10.1016/j.landurbplan.2011.12.012.
7. De Risi, R., Jalayer, F., de Paola, F. and Lindley, S. (2018) ‘Delineation of flooding risk hotspots based on digital elevation model, calculated and historical flooding extents: the case of Ouagadougou’, Stochastic Environmental Research and Risk Assessment, 32(6), pp. 1545–1559. doi:10.1007/s00477-017-1450-8.
8. Ertan, S. and Çelik, R.N. (2021) ‘The assessment of urbanization effect and sustainable drainage solutions on flood hazard by GIS’, Sustainability, 13(4), 2293. doi:10.3390/su13042293.
9. Fletcher, T.D., Andrieu, H. and Hamel, P. (2013) ‘Understanding, management and modelling of urban hydrology and its consequences for receiving waters: A state of the art’, Advances in Water Resources, 51, pp. 261–279. doi:10.1016/j.advwatres.2012.09.001.
10. Green, D., O'Donnell, E., Johnson, M., Slater, L., Thorne, C., Zheng, S., Stirling, R., Chan, F.K.S., Li, L. and Boothroyd, R.J. (2021) ‘Green infrastructure: The future of urban flood risk management?’, WIREs Water, 8(6), e1560. doi:10.1002/wat2.1560.
11. Hamel, P., Daly, E. and Fletcher, T.D. (2013) ‘Source-control stormwater management for mitigating the impacts of urbanisation on baseflow: A review’, Journal of Hydrology, 485, pp. 201–211. doi:10.1016/j.jhydrol.2013.01.001.
12. Hollis, G.E. (1975) ‘The effect of urbanization on floods of different recurrence interval’, Water Resources Research, 11(3), pp. 431–435. https://doi:10.1029/WR011i003p00431.
13. Huong, H.T.L. and Pathirana, A. (2013) ‘Urbanization and climate change impacts on future urban flooding in Can Tho city, Vietnam’, Hydrology and Earth System Sciences, 17(1), pp. 379–394. doi:10.5194/hess-17-379-2013.
14. Khosravi, K., Nohani, E., Maroufinia, E. and Pourghasemi, H.R. (2016) ‘A GIS-based flood susceptibility assessment and its mapping in Iran: a comparison between frequency ratio and weights-of-evidence bivariate statistical models with multi-criteria decision-making technique’, Natural Hazards, 83(2), pp. 947–987. doi:10.1007/s11069-016-2357-2.
15. Leopold, L.B. (1968) Hydrology for urban land planning: A guidebook on the hydrologic effects of urban land use. U.S. Geological Survey Circular 554. Washington, DC: U.S. Geological Survey. doi:10.3133/cir554.
16. Nithila Devi, N., Ganapathy, A., Silva, A.F.R., Vorogushyn, S., Apel, H., Kreibich, H., Oostwegel, L.J.N., Kuiry, S.N. and Sairam, N. (2025) ‘Lost water bodies and a flooded city – Counterfactual scenarios of the extreme Chennai flood highlight the potential of nature-based solutions’, Urban Climate, 61, 102454. doi:10.1016/j.uclim.2025.102454.
17. Nithila Devi, N., Sridharan, B. and Kuiry, S.N. (2019) ‘Impact of urban sprawl on future flooding in Chennai city, India’, Journal of Hydrology, 574, pp. 486–496. doi:10.1016/j.jhydrol.2019.04.041.
18. Ogden, F.L., Pradhan, N.R., Downer, C.W. and Zahner, J.A. (2011) ‘Relative importance of impervious area, drainage density, width function, and subsurface storm drainage on flood runoff from an urbanized catchment’, Water Resources Research, 47(12), W12503. doi:10.1029/2011WR010550.
19. Oswald, C.J., Kelleher, C., Ledford, S.H., Hopkins, K.G., Sytsma, A., Tetzlaff, D., Toran, L. and Voter, C. (2023) ‘Integrating urban water fluxes and moving beyond impervious surface cover: A review’, Journal of Hydrology, 618, 129188. doi:10.1016/j.jhydrol.2023.129188
20. Shuster, W.D., Bonta, J., Thurston, H., Warnemuende, E. and Smith, D.R. (2005) ‘Impacts of impervious surface on watershed hydrology: A review’, Urban Water Journal, 2(4), pp. 263–275. doi:10.1080/15730620500386529.
21. Suriya, S. and Mudgal, B.V. (2012) ‘Impact of urbanization on flooding: The Thirusoolam sub watershed – A case study’, Journal of Hydrology, 412–413, pp. 210–219. doi:10.1016/j.jhydrol.2011.05.008.
22. Tomar, P., Singh, S.K., Kanga, S., Meraj, G., Kranjčić, N., Đurin, B. and Pattanaik, A. (2021) ‘GIS-Based Urban Flood Risk Assessment and Management—A Case Study of Delhi National Capital Territory (NCT), India’, Sustainability, 13(22), 12850. doi:10.3390/su132212850.
23. Zope, P., Eldho, T.I. and Jothiprakash, V. (2015) ‘Impacts of urbanization on flooding of a coastal urban catchment: a case study of Mumbai City, India’, Natural Hazards, 75(1), pp. 887–908. doi:10.1007/s11069-014-1356-4.
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