The catchment bassin of Mouhoun, the largest in Burkina Faso, has experienced particularly severe flood and low water events over the last years. In view of the recurrence of these exceptional events, the estimation and the predetermination of extreme quantiles of floods discharge and low discharge are a strategic axis for prevention against floods and drought in this region. To do this, the generalized Pareto (GPA or gpa) model and the Log normal type 3 (LN3 or ln3) distributions were used respectively for the flood flows and for the sample of annual low flows of the Mouhoun river at the Samendeni hydrometric station in Burkina Faso. The statistical tests of homogeneity, stationarity and independence were verified. The different frequency models or statistical distributions were evaluated in order to choose the most appropriate model. The parameters of the selected models were determined with satisfactory quality criteria and then used to predetermine the 100-year flood return period and distribution water quantiles. The results obtained show that the values of flood and low water having a return period of 100 years in the Mouhoun basin at the samendeni station are respectively 574.52 m3/s et 0.01 m3/s. The 100-year flood has been exceeded at least once with a value of 587.4 m3/s.
Keywords: predetermination, flood discharge, low discharge, Samendeni, Burkina Faso