Author(s): Gert Leyssen; Els Van Uytven; Frederik Zoeter; Joris Blanckaert; Roeland Adams; Tim Franken; Jiri Nossent; Fernando Pereira

Linked Author(s): Gert Leyssen, Fernando Pereira

Keywords: Flooding; Uncertainty; Extreme value; Climate change; Copul

Abstract: Extreme water levels in rivers are the result of a combination of extreme upstream discharges and extreme downstream boundaries, like water level and wind events, that have a changing effect over the span of the river. We present a methodology that can describe the extreme domain of different interacting drivers by a nested Copula based on the individual univariate extreme value distributions of each of them. The approach reduces the computation time, but simultaneously recognizes the importance of robust results and the consideration of the different sources of uncertainty. By stratification of the probability domain for extreme events a set of hydrodynamic boundary conditions, synthetic events, are generated. Each of these synthetic events gets a probability of occurrence, which changes according to either the considered confidence level. The methodology is applied on rainfall for multiple climate horizons (2050,2075,2100 and 2125) and combined with different projections of sea level rise. The stratification approach allowed the selection and rescaling of synthetic reference events for any desired climate change projection. This subset of the synthetic events can be used as design events for a specific area and are representative for the full set of events.

DOI: https://doi.org/10.3850/978-90-833476-1-5_iahr40wc-p0519-cd

Year: 2023