What Drives Uncertainty Surrounding Riverine Flood Risks?

Abstract

Flooding drives considerable risks. Designing strategies to manage these risks is complicated by the often large uncertainty surrounding flood risk projections. Uncertainty surrounding riverine flood risks can stem from choices regarding boundary conditions, model structures, and parameters as well as interactions among hazards, exposures, and vulnerabilities. Flood risk assessment involves multiple research disciplines including the fields of atmospheric science, hydrology, and socioeconomics. A quantitative understanding of which factors contribute most to uncertainties surrounding flood hazards and risks can inform the design of mission-oriented research. Here we analyze a case study to rank the drivers of uncertainties surrounding riverine flood hazards and risks. We find that the projected flood risk is most sensitive to factors associated with flood hazards, rather than exposure and vulnerability: upstream discharge, river bed elevation, channel roughness, and the digital elevation model resolution. Our framework and results can help to improve flood-hazard and risk projections.

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“…When assessments account for these uncertainties, the procedures tend to be heuristic and not calibrated with data (40,47,48,118,122).…”