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Impulse response of a linear diffusion analogy model as a flood frequency probability density function |
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| Authors: | WITOLD G STRUPCZEWSKI VIJAY P SINGH STANISLAW WEGLARCZYK |
| Institution: | 1. Water Resources Department , Institute of Geophysics, Polish Academy of Sciences , Ksiecia Janusza 64, 01-452, Warsaw, Poland E-mail: wgs@igf.edu.pl;2. Department of Civil and Environmental Engineering , Louisiana State University , Baton Rouge, Louisiana, 70803-6405, USA E-mail: cesing@lsu.edu;3. Institute of Water Engineering and Water Management, Cracow University of Technology , Warszawska 24, 31-155, Cracow, Poland E-mail: sweglar@lajkonik.wis.pk.edu.pl |
| Abstract: | Abstract The impulse response of a linear convective-diffusion analogy (LD) model used for flow routing in open channels is proposed as a probability distribution for flood frequency analysis. The flood frequency model has two parameters, which are derived using the methods of moments and maximum likelihood. Also derived are errors in quantiles for these parameter estimation methods. The distribution shows that the two methods are equivalent in terms of producing mean values—the important property in case of unknown true distribution function. The flood frequency model is tested using annual peak discharges for the gauging sections of 39 Polish rivers where the average value of the ratio of the coefficient of skewness to the coefficient of variation equals about 2.52, a value closer to the ratio of the LD model than to the gamma or the lognormal model. The likelihood ratio indicates the preference of the LD over the lognormal for 27 out of 39 cases. It is found that the proposed flood frequency model represents flood frequency characteristics well (measured by the moment ratio) when the LD flood routing model is likely to be the best of all linear flow routing models. |
| Keywords: | flood frequency probability distribution diffusion model lognormal model moments quantiles method of moments maximum likelihood standard error statistical tests time series Poland |