Performance of Boreholes Capturing the Aquifers Systems in the Crystalline Peneplain of Benin

Abstract

The water supply in the regions of the crystalline peneplain of Benin is ensured by the mobilization of groundwater. The objective of this study is to assess the productivity of fractured and/or fissured aquifers in the communes of Nikki, N'Dali and Pèrèrè located in northern Benin. The methodological approach is based on the comparative analysis of the physical and hydrodynamic parameters of the catchment structures associated with the interpretation of pumping tests of long and short durations combined. It appears from this study that the most productive depths are between 21.6 and 76 m. Some of the boreholes studied (32.37%) have a low flow rate. The transmissivity values vary from 3.06.10 − 5 to 6.95.10 − 4 m 2 /s with an average of 2.38.10 − 4 m 2 /s; the specific flow varies from 0.25 to 2.20 m 2 /h with an average of 0.82 m 3 /h. The classification of the distribution of flows and transmissivities established by the Lasm criterion (2000) showed that most of the boreholes have high transmissivities, which are witnesses of productive boreholes in the study area.