Journal cover Journal topic
Hydrology and Earth System Sciences An interactive open-access journal of the European Geosciences Union
Hydrol. Earth Syst. Sci., 21, 2219-2232, 2017
https://doi.org/10.5194/hess-21-2219-2017
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
26 Apr 2017
Topography- and nightlight-based national flood risk assessment in Canada
Amin Elshorbagy1,2, Raja Bharath1, Anchit Lakhanpal1, Serena Ceola3, Alberto Montanari3, and Karl-Erich Lindenschmidt2,4 1Department of Civil, Geological, and Environmental Engineering, University of Saskatchewan, Saskatoon, Canada
2Global Institute for Water Security, University of Saskatchewan, Saskatoon, Canada
3Department of Civil, Chemical, Environmental, and Materials Engineering, University of Bologna, Bologna, Italy
4School of Environment and Sustainability, University of Saskatchewan, Saskatoon, Canada
Abstract. In Canada, flood analysis and water resource management, in general, are tasks conducted at the provincial level; therefore, unified national-scale approaches to water-related problems are uncommon. In this study, a national-scale flood risk assessment approach is proposed and developed. The study focuses on using global and national datasets available with various resolutions to create flood risk maps. First, a flood hazard map of Canada is developed using topography-based parameters derived from digital elevation models, namely, elevation above nearest drainage (EAND) and distance from nearest drainage (DFND). This flood hazard mapping method is tested on a smaller area around the city of Calgary, Alberta, against a flood inundation map produced by the city using hydraulic modelling. Second, a flood exposure map of Canada is developed using a land-use map and the satellite-based nightlight luminosity data as two exposure parameters. Third, an economic flood risk map is produced, and subsequently overlaid with population density information to produce a socioeconomic flood risk map for Canada. All three maps of hazard, exposure, and risk are classified into five classes, ranging from very low to severe. A simple way to include flood protection measures in hazard estimation is also demonstrated using the example of the city of Winnipeg, Manitoba. This could be done for the entire country if information on flood protection across Canada were available. The evaluation of the flood hazard map shows that the topography-based method adopted in this study is both practical and reliable for large-scale analysis. Sensitivity analysis regarding the resolution of the digital elevation model is needed to identify the resolution that is fine enough for reliable hazard mapping, but coarse enough for computational tractability. The nightlight data are found to be useful for exposure and risk mapping in Canada; however, uncertainty analysis should be conducted to investigate the effect of the overglow phenomenon on flood risk mapping.

Citation: Elshorbagy, A., Bharath, R., Lakhanpal, A., Ceola, S., Montanari, A., and Lindenschmidt, K.-E.: Topography- and nightlight-based national flood risk assessment in Canada, Hydrol. Earth Syst. Sci., 21, 2219-2232, https://doi.org/10.5194/hess-21-2219-2017, 2017.
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Short summary
Flood mapping is one of Canada's major national interests. This work presents a simple and effective method for large-scale flood hazard and risk mapping, applied in this study to Canada. Readily available data, such as remote sensing night-light data, topography, and stream network were used to create the maps.
Flood mapping is one of Canada's major national interests. This work presents a simple and...
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