Dépôt numérique

Treatment of Zeroes in Tail Modeling of Low Flows.

Durrans, S. Rocky; Ouarda, Taha B. M. J.; Rasmussen, Peter F. et Bobée, Bernard (1999). Treatment of Zeroes in Tail Modeling of Low Flows. Journal of Hydrologic Engineering , vol. 4 , nº 1. pp. 19-27. DOI: 10.1061/(ASCE)1084-0699(1999)4:1(19).

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The presence of zeroes in a record of low flows usually has been interpreted as being indicative of a stream that goes dry during some periods. However, in some instances, zeroes may appear in a gauging record simply because the actual discharge was below a measurement threshold. For example, in some regions it is sometimes true that the lower limit of a stream gauge is above the true stream bottom, and any (censored) discharges not registered by the gauges are recorded as zeroes. This paper presents a comparison of alternative methods for treatment of zeroes in low-flow estimation procedures when tail models are employed for modeling purposes. Simulation experiments indicate that a Weibull tail model, as fitted using a likelihood-based method for inclusion of censored data, is the best estimator of the 10-year low-flow quantile when zeroes in a data set have arisen as a consequence of censoring. When zeroes in a data set exist because the stream is an ephemeral one, a lognormal mixed tail model fitted using maximum likelihood is the best performer. When one is not sure whether zeroes in a data set are real, it is recommended that the 10-year low-flow quantile be estimated by treating the zeroes as censored values and performing the estimation using the Weibull tail model fitted using maximum likelihood.

Type de document: Article
Mots-clés libres: water discharge measurement; hydrologic data; water discharge; stream gauge; comparative studies; river and stream beds; rivers and streams; low flow
Centre: Centre Eau Terre Environnement
Date de dépôt: 03 févr. 2021 19:42
Dernière modification: 03 févr. 2021 19:42
URI: https://espace.inrs.ca/id/eprint/11142

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