Analysis of Rainfall Variability on the Groundwater Levels of Wells in the Nouaho Basin in East-Central Burkina Faso

Abstract

Sahelian countries are confronted with a lack of reliable data on water and climate allowing them to understand the effects of climate variability. To address this situation, with the support of Water Aid, we have collected rainfall data and groundwater level in wells from 2012 to 2018 with help of local populations. Their contribution made it possible to cover a wider geographical area and to obtain the data necessary to analyze the climate variability on a small and large scale in the sub-basin of the Nouhao. The data collected are well correlated with those collected from the rain gauges of the national meteorological agency in the region of Fada N’Gourma. From 2012 to 2018, August appears to be the rainiest month. It recorded, alone, 1/3 of the average annual rainfall. The depletion of surface water tables is faster after the rainy season. The static level of the water table in the crystalline subsoil also depletes and replenishes at night after the peak water collection time, which is between noon and 8 p.m. These few years of measuring rainfall and groundwater fluctuations have shown that the correlation between rainfall and groundwater level is clearly established. Nevertheless this needs to be more investigated during a longer period to confirm the robustness of the method. On the other hand, the approach to securing water resources based on community monitoring of water resources gives good results in accordance with the National Meteorological Agency and the Directorate of water resources, however, caution recommends continuing measurements over a few decades to confirm its robustness for this aspect too.