Influence des changements d’utilisation des terres sur les débits du bassin versant du Massili à Gonsé (Burkina Faso)

This study aims to determine the contribution of land use changes on runoff in the Massili basin in Gonsé. The study methodology is based on the analysis of the temporal variability of rainfall (1975-2019) and discharge (1975-2019) and the diachronic analysis of land use (1975-1991-2007-2019). The statistical tools used are Pettitt’s test, Hubert’s segmentation procedure, Mann-Kendall test and Pearson’s correlation test. The results show that the Massili catchment area experienced a long dry period from 1975-2001 and a wet phase from 2002-2019. The breakpoint detection test highlighted changepoints in 2002 and 2003 (Pettitt), 2004, 2008 and 2019 (Hubert’s segmentation) with increase ranging from 64,55% to 95,76% after the breaks. Significant upward trends were observed for monthly and annual flows. The Pearson test reveals a low correlation between rainfall and discharge with values between 0,141 and 0,225. These findings show that the evolution discharge is affected by the regression rate of the savannahs of -79,69% and riparian formations of -14,84%, to the benefit for urban areas of 1006,65%, the bare soil of 388,92% and agricultural area of 79,92%, favorable to runoff. The results shed light on the causes of streamflow variability and might be useful in framing integrated land and water resources management policies

Influence des changements d’utilisation des terres sur les débits du bassin versant du Massili à Gonsé (Burkina Faso)

La présente étude vise à déterminer la contribution des changements d’utilisation des terres sur les écoulements dans le bassin du Massili à Gonsé (Burkina Faso). Elle s’appuie sur l’étude de la variabilité temporelle des précipitations (1975-2019) et des débits (1975-2019) et l’analyse diachronique de l’occupation des terres (1975-1991-2007-2019). Les outils statistiques utilisés sont les tests de Pettitt, la segmentation de Hubert, le test de Mann-Kendall et le test de corrélation de Pearson. Les résultats montrent que le bassin versant du Massili a connu une longue période sèche de 1975 à 2001 et une phase humide de 2002 à 2019. L’analyse des débits a permis d’identifier des ruptures en 2002 et 2003 (Pettitt) et 2004, 2008 et 2019 (Segmentation de Hubert) avec des hausses comprises entre 64,55% à 95,76% après les ruptures. Des tendances significatives à la hausse ont été observées sur les débits mensuels et annuels. Le test de Pearson révèle une faible corrélation entre la pluie et les débits avec des valeurs comprises entre 0,141-0,225. La tendance des débits est en relation avec la dynamique de l’occupation des terres marquée par un taux de régression de -79,69% des savanes et de -14,84% des formations ripicoles, au bénéfice de l’habitat de 1006,65%, des sols nus de 388,92% et des zones de culture de 79,92%, favorables au ruissellement. Ces résultats apportent des éléments indicatifs sur les causes de variabilité des écoulements et sont utiles pour la gestion intégrée des sols et des ressources en eau du bassin de Gonsé.This study aims to determine the contribution of land use changes on runoff in the Massili basin in Gonsé. The study methodology is based on the analysis of the temporal variability of rainfall (1975-2019) and discharge (1975-2019) and the diachronic analysis of land use (1975-1991-2007-2019). The statistical tools used are Pettitt’s test, Hubert’s segmentation procedure, Mann-Kendall test and Pearson’s correlation test. The results show that the Massili catchment area experienced a long dry period from 1975-2001 and a wet phase from 2002-2019. The breakpoint detection test highlighted changepoints in 2002 and 2003 (Pettitt), 2004, 2008 and 2019 (Hubert’s segmentation) with increase ranging from 64,55% to 95,76% after the breaks. Significant upward trends were observed for monthly and annual flows. The Pearson test reveals a low correlation between rainfall and discharge with values between 0,141 and 0,225. These findings show that the evolution discharge is affected by the regression rate of the savannahs of -79,69% and riparian formations of -14,84%, to the benefit for urban areas of 1006,65%, the bare soil of 388,92% and agricultural area of 79,92%, favorable to runoff. The results shed light on the causes of streamflow variability and might be useful in framing integrated land and water resources management policies

Influence des changements d’utilisation des terres sur les débits du bassin versant du Massili à Gonsé (Burkina Faso)

This study aims to determine the contribution of land use changes on runoff in the Massili basin in Gonsé. The study methodology is based on the analysis of the temporal variability of rainfall (1975-2019) and discharge (1975-2019) and the diachronic analysis of land use (1975-1991-2007-2019). The statistical tools used are Pettitt’s test, Hubert’s segmentation procedure, Mann-Kendall test and Pearson’s correlation test. The results show that the Massili catchment area experienced a long dry period from 1975-2001 and a wet phase from 2002-2019. The breakpoint detection test highlighted changepoints in 2002 and 2003 (Pettitt), 2004, 2008 and 2019 (Hubert’s segmentation) with increase ranging from 64,55% to 95,76% after the breaks. Significant upward trends were observed for monthly and annual flows. The Pearson test reveals a low correlation between rainfall and discharge with values between 0,141 and 0,225. These findings show that the evolution discharge is affected by the regression rate of the savannahs of -79,69% and riparian formations of -14,84%, to the benefit for urban areas of 1006,65%, the bare soil of 388,92% and agricultural area of 79,92%, favorable to runoff. The results shed light on the causes of streamflow variability and might be useful in framing integrated land and water resources management policies