Representative ensemble for simulation of extreme floods
This work proposes methods for reducing the computational requirements of hydrological simulations for the estimation of very rare floods that occur on average less than once in 1000 years. These methods enable the analysis of long time streamflow series (here for example 10 000 years) at low computational costs with representing modelling uncertainty. They are to be used within continuous simulation frameworks with long input time series and are readily transferable to similar simulation tasks.
We propose three methods for reducing the computational requirements for the hydrological simulations for extreme flood estimation. These methods rely on simulation of annual maxima (maximal flow within a year) and on analyzing their simulated range to downsize the hydrological parameter ensemble to a small number suitable for continuous simulation frameworks (with long streamflow time series). The methods are tested in a Swiss catchment with 10000 years of synthetic streamflow data simulated with a hydrologic model fed with inputs from a weather generator.
Our results demonstrate the reliability of the proposed downsizing methods for robust simulations of extreme floods with uncertainty. The methods are readily transferable to other situations where ensemble simulations are needed.
Sikorska-Senoner, A.E., Schaefli, B., and Seibert, J. (2020) Downsizing parameter ensembles for simulations of extreme floods, Nat. Hazards Earth Syst. Sci. Discuss., https://doi.org/10.5194/nhess-2020-79, in review.