In: Contributions to Geophysics and Geodesy, vol. 40, no. 2
Ladislav Gaál - Ján Szolgay - Silvia Kohnová - Kamila Hlavčová - Alberto Viglione
Inclusion of historical information in flood frequency analysis using a Bayesian MCMC technique: a case study for the power dam Orlík, Czech Republic
Year, pages: 2010, 121 - 147
Keywords: flood frequency analysis, historical floods, Bayesian inference, Markov chain Monte Carlo simulations, likelihood function, confidence intervals
The paper deals with at-site flood frequency estimation in the case when also information on hydrological events from the past with extraordinary magnitude are available. For the joint frequency analysis of systematic observations and historical data, respectively, the Bayesian framework is chosen, which, through adequately defined likelihood functions, allows for incorporation of different sources of hydrological information, e.g., maximum annual flood peaks, historical events as well as measurement errors. The distribution of the parameters of the fitted distribution function and the confidence intervals of the flood quantiles are derived by means of the Markov chain Monte Carlo simulation (MCMC) technique.
The paper presents a sensitivity analysis related to the choice of the most influential parameters of the statistical model, which are the length of the historical period h and the perception threshold X0. These are involved in the statistical model under the assumption that except for the events termed as 'historical' ones, none of the (unknown) peak discharges from the historical period h should have exceeded the threshold X0. Both higher values of h and lower values of X0 lead to narrower confidence intervals of the estimated flood quantiles; however, it is emphasized that one should be prudent of selecting those parameters, in order to avoid making inferences with wrong assumptions on the unknown hydrological events having occurred in the past.
The Bayesian MCMC methodology is presented on the example of the maximum discharges observed during the warm half year at the station Vltava-Kamýk (Czech Republic) in the period 18777–2002. Although the 2002 flood peak, which is related to the vast flooding that affected a large part of Central Europe at that time, occurred in the near past, in the analysis it is treated virtually as a 'historical' event in order to illustrate some crucial aspects of including information on extreme historical floods into at-site flood frequency analyses.
How to cite:
Gaál, L., Szolgay, J., Kohnová, S., Hlavčová, K., Viglione, A. 2010. Inclusion of historical information in flood frequency analysis using a Bayesian MCMC technique: a case study for the power dam Orlík, Czech Republic. In Contributions to Geophysics and Geodesy, vol. 40, no.2, pp. 121-147.
Gaál, L., Szolgay, J., Kohnová, S., Hlavčová, K., Viglione, A. (2010). Inclusion of historical information in flood frequency analysis using a Bayesian MCMC technique: a case study for the power dam Orlík, Czech Republic. Contributions to Geophysics and Geodesy, 40(2), 121-147.