Groundwater Storage Change Estimation Using Combination of Hydrogeophysical and Groundwater Table Fluctuation Methods in Hard Rock Aquifers

Mahamadou Koïta,Hamma Yonli,Donissongou Soro,Amagana Dara,Jean-Michel Vouillamoz

doi:10.3390/resources7010005

Abstract

This study aims to estimate the groundwater storage change of hard rock aquifers in the face of change. For this, the approach developed consisted initially in the implementation of 5 Magnetic Resonance Soundings (MRS) around the observation wells realized and monitored from 2014 to 2015 in the Sanon experimental site. In a second step, we determined the storage change using the MRS data and the water table fluctuation method. The MRS data show that the water content varies spatially from 4.5 to 1.3%. The maximum value is recorded at the central valley where a piezometric dome is observed. The specific yield varies from 2.4% in the central valley to 1.3% at the outlet. The renewed water resource is estimated at 116 mm in the central valley and 32 mm at the outlet, which corresponds respectively to 13 and 3% of the annual rainfall. The renewed water resource is consistent with the annual recharge. Thus, the combination of the MRS geophysical approach and water table fluctuation method is an efficient, fast and cheaper (compared with long-term pumping test) tool for the estimation of groundwater storage changes.

Highlights

IntroductionThe high amount of almost dry holes (typically ranging between 25 and 60%) confirms the complexity of hard rock aquifers which is controlled by several factors and it did not allow the African population to use groundwater resources for irrigation and drinking water when rain and surface water are lacking
Groundwater resources in hard rocks play a major role in the water supply of millions of people in Africa
The high amount of almost dry holes confirms the complexity of hard rock aquifers which is controlled by several factors and it did not allow the African population to use groundwater resources for irrigation and drinking water when rain and surface water are lacking

Summary

Introduction

The high amount of almost dry holes (typically ranging between 25 and 60%) confirms the complexity of hard rock aquifers which is controlled by several factors and it did not allow the African population to use groundwater resources for irrigation and drinking water when rain and surface water are lacking. The countries of Sahelian regions face several challenges in relation to the availability and exploitation of water resources (high population growth, rapid urbanization, economic pressures and climate change). Faced with such a situation, groundwater resources whose vulnerability to drought is low [2] seem to be the best alternative to respond to this emergency and adaptation to the impacts

Objectives

Results

Conclusion