Water resources modeling in a context of climate change in Burkina Faso

Abstract

This study aims to characterize climate variability in Burkina Faso. The data collected for this research concern daily rainfall recorded in nineteen stations and covering the period 1950-2000. Statistical tests were applied to analyze rainfall variability. The ETCCDI indices made it possible to characterize rainfall extremes. The standardized precipitation index was used to determine dry and wet periods. The results obtained from the analysis of daily rainfall data show that during the period 1950-2000, rainfall is characterized by an alternation of wet phases (1960-1970) and (1971-1993) and a decreasing trend in annual precipitation. In addition, the interannual variability of rainfall is marked by breaks in stationarity in the series. Pettitt's statistical test shows breaks occurring around 1964-1970 and 1970-1976. There is a severe drought over the period 1980-1990 with immediate consequences for agriculture and livestock. Indeed, the annual number of rainy days is increasing only in Zorgho locality while it is decreasing in the other eighteen localities. The frequency of 50 mm, extreme and intense rainfall has been increasing since the end of the 1980s, with a rise from 1990 to 2000. The results of the standardized precipitation index were used to determine the dry (1970-1980) and wet (1950- 1970) periods. The years after 1990 alternate between dry and wet periods. The Sahelian zone facing major challenges related to water use has been the subject of studies on the qualitative and quantitative problems of flows at the outflow of these catchment areas. For this reason, we have worked on five basins (Boromo, Yendere, Wayen, Samandeni and Dapola) to understand the hydrological functioning of the watershed. For this reason, a hydrological model is necessary and is becoming an essential tool in the understanding of the hydrological functioning of the catchment area and in the rational use of water resources as well as in the fight against natural disasters related to floods. This part of the study approaches the rain-flow modelling based on the GR2M Mouehli version models. First, we sought to identify the most suitable optimization criterion that would best reproduce the observed flows, then we identified the most efficient model on the catchment area. A sensitivity analysis of the parameters of each model enabled us to identify the most sensitive parameters and how they impact each model