Comparative Assessment of Urban Flood Risks due to Urbanization and Climate Change in the Turnhout Valley of Belgium
DOI:
https://doi.org/10.18034/abcjar.v3i1.27Keywords:
Urbanization, climate change, river flood model, urban runoff, flood risk, composite hydrographAbstract
The combined effect of urbanization and climate change on catchment runoff has been drawing attention in the recent years to assess the impact of climate change on urbanizing catchments. There has been extensive development of paved areas within the city of Turnhout in Belgium in combination with several modifications of the neighbouring rivers. Moreover, the city authority has decided to encourage more densification of housing and industries within or next to the cores, which would lead to frequent overflows out of the existing combined sewer system. This combination leads to a faster flow of larger quantities of water which physically cannot be retained by the valleys over this region and thus causes increasingly frequent and harmful flood events affecting agricultural lands. The situation could be indisputably exacerbated under climate change scenarios. This study focuses on assessing the effects of urban development and climate change on flood risks in the downstream of Turnhout. For this study, a lumped conceptual hydrological model NAM was developed for generating runoff from the catchment. The CCI-HYDR perturbation tool, developed by Katholieke Universiteit Leuven, was applied to generate time series of future rainfall and evapotranspiration. The urban runoffs were obtained from the simulation of existing InfoWorks CS model under both current and climate change (A1B, A2, B1 and B2) scenarios. Rainfall-runoff was then uniformly distributed along the river reaches and urban runoff was applied as point source boundary conditions in the calibrated and validated MIKE 11 river flood model. Composite hydrographs with different return periods for all the boundary conditions were generated through extreme value analysis. The results show intensified and more frequent peak runoff resulting from combined effect of urbanization and climate change, in comparison to the individual effect of urbanization or climate change each. The increased peak runoff in the river due to heavy rainfall coinciding with development of paved surfaces within the city would lead to severe urban flooding when urbanization and climate change scenarios are accounted for.
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Chang, H. J. (2007) Comparative streamflow characteristics in urbanizing basins in the Portland Metropolitan Area, Oregon, USA. Hydrological Processes 21(2), 211-222.
DHI. (2008) MIKE 11 A modelling system for rivers and channels, Reference and User Manual. DHI Water & Environment, Hørsholm, Denmark.
Franczyk, J. and Chang, H. (2009) The effects of climate change and urbanization on the runoff of the Rock Creek basin in the Portland metropolitan area, Oregon, USA. Hydrological Processes 23, 805-815.
Georgiyevsky, V. and Shiklomanov I. (2003) In World Water Resources at the Beginning of the 21st Century. Cambridge University Press, Cambridge.
Huntington, T. G. (2006) Evidence for intensification of the global water cycle: Review and synthesis. Journal of Hydrology 319(1-4), 83-95.
Ntegeka, V. (2006) An empirical statistical approach to climate change impact on hydroclimatic extremes. Master thesis, K. U. Leuven and V.U.B., Belgium.
Ntegeka, V. and Willems, P. (2008) CCI-HYDR Perturbation Tool: a climate change tool for generating perturbed time series for the Belgian climate. Catholic University of Leuven & Royal Meteorological Institute of Belgium, Manual, December Version, 1-7.
Semadeni-Davies, A., Hernebring, C. et al. (2008) The impacts of climate change and urbanisation on drainage in Helsingborg, Sweden: Combined sewer system. Journal of Hydrology 350(1-2), 100-113.
Semadeni-Davies, A., Hernebring, C. et al. (2008) The impacts of climate change and urbanisation on drainage in Helsingborg, Sweden: Suburban stormwater. Journal of Hydrology 350(1-2), 114-125.
Timbe, L. (2007) River flooding analysis using quasi-2D hydraulic modelling and geospatial data. PhD thesis, Catholic University of Leuven, Faculty of Engineering, Leuven, Belgium.
Tu, J. (2009) Combined impact of climate and land use changes on streamflow and water quality in eastern Massachusetts, USA. Journal of Hydrology 379(3-4), 268-283.
Vaes, G., Willems, P. and Berlamont, J. (2000) Selecetion and composition of representative hydrographs for the river design calculations. In: ERB 2000, Int. Coference on 'Monitoring and modelling catchment water quantity and quality' (ERB), 27-29 September 2000 Gent, 53-55.
Vorosmarty, C. J., P. Green, et al. (2000) Global water resources: Vulnerability from climate change acid population growth. Science 289(5477), 284-288.
Wallingford. (2009) InfoWorks RS Help Documaentation, Version 10.5, Wallingford Software, United Kingdom.
White, M.D. and Greer, K.A. (2006) The effects of watershed urbanization on the stream hydrology nd riparian vegetation of Los Peñasquitos Creek, California. Landscape and Urban Planning 74, 125–138.
Yperesele, V. (2004) Impacts of climate change in Belgium. Report commissioned by Greenpeace.
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