301. CLIMATE VARIABILITY AND ITS IMPACT ON WATER RESOURCES IN THE LOWER MONO RIVER VALLEY IN BENIN FROM 1960 TO 2018.
- Author
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T. R., NAKOU, L., SENOU, B., ELEGBEDE, and F. P., CODO
- Subjects
WATER supply ,GROUNDWATER management ,WATERSHEDS ,STATISTICAL hypothesis testing ,DROUGHTS ,RAINFALL ,RAIN gauges - Abstract
Climate change has an influence on rainfall, which significantly affects the magnitude of the frequency of floods and droughts. Variations in precipitation over the long term are therefore one of the elements of climate variability. To identify the change, the quantification of the environmental change that has already occurred in the Beninese portion of the Mono River Basin (lower valley) and to understand the impact of this change on the water resources of the basin, for a better future adaptation, the annual rainfall and hydrological data for each station in the basin were compiled over a period of 58 years (1960 to 2018). These data were aggregated to the basin scale based on the standardized Lamb anomaly index before being attached to the 2nd order HANNING low-pass filter to extract bright periods over the basin. Then, Pettitt's and Hubert's rupture detection tests at the significance level of the Scheffé test made it possible to study the homogeneity of the different series. Finally, a hydrological balance over each detected period was carried out to determine the real infiltration rate in the underground reservoirs of the basin. The results show that the rainfall regime of the Mono River basin in Benin (lower valley) experienced two breaking points in 1968 and 2007, which show three subperiods: 1960-1968, 1969-2007 and 2008-2018. Thus, compared to the 1960-1968 subperiod, the Beninese portion of the Mono River basin (lower valley) experienced a 21% rainfall deficit period from 1969-2007 and a 10% rainfall surplus period between 2008-2018. The hydrological balance of the basin carried out over each subperiod detected is in deficit. Before the first rupture (1960-1968), the recharge rate in the underground reservoirs of the basin was 12.73%. This rate rose after the first break (1969-2007) to 1.57%. That is, 87.64% of the recharge deficit compared to the reference period and represents more than 4 times the rainfall deficit, against 5.78% of the recharge rate between 2008 and 2018. Through this article, good management of groundwater resources in the lower Mono River valley proves necessary in the case of unfavorable climatic conditions. [ABSTRACT FROM AUTHOR]
- Published
- 2023