La Houille Blanche
Number 6, Décembre 2003
|Page(s)||27 - 33|
|Published online||01 July 2009|
Estimation des valeurs extrêmes de débits maximaux annuels en Tunisie : un retour par l'approche multifractale
Estimation of peak annual river discharges in Tunisia: a Multiscaling approach
Ecole Nationale d'Ingénieurs de Tunis.
2 Intitut National des Sciences Appliquées et de Technologie.
Following Eagleson (1967), the river discharge Q(S, t) may be considered as a time-space process of the basin area S and the time t. Thus, for an given rainfall event, the peak discharge Qmax (S) is a spatial process according to the watershed area. And its multifractal behavior (Lovejoy and Schertzer (1995 a and b) ; Pandey and al. (1998) is investigated. Estimated parameters for multiplicative cascade model are the multifractal index α =1.77, the codimension of the mean C1 = 0.1 and the deviation from conservation conditions H = 0.414. We find that the critical moment after which statistical moments diverge in the observed series is qD = 2.2. Developments about consequences for the hydrologic risk assessment (p is the non exceedance value) lead to Rλp ∝ p-0.45. They constitute an objective basis for the development of runoff-area regression relationships. Owing to the hyperbolic rather than exponential probability tail, this method leads to estimated quantiles for T = 100 years and 1 000 years which are greater then those we obtained through regional and frequency approachs.
© Société Hydrotechnique de France, 2003
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.