Accurately assessing groundwater storage changes in Niger is critical for long-term water
resource management but is difficult due to sparse field data. We present a study of groundwater
storage changes and recharge in Southern Niger, computed using data from NASA Gravity Recovery
and Climate Experiment (GRACE) mission. We compute a groundwater storage anomaly estimate
by subtracting the surface water anomaly provided by the Global Land Data Assimilation System
(GLDAS) model from the GRACE total water storage anomaly. We use a statistical model to fill
gaps in the GRACE data. We analyze the time period from 2002 to 2021, which corresponds to the
life span of the GRACE mission, and show that there is little change in groundwater storage from
2002–2010, but a steep rise in storage from 2010–2021, which can partially be explained by a period
of increased precipitation. We use the Water Table Fluctuation method to estimate recharge rates
over this period and compare these values with previous estimates. We show that for the time range
analyzed, groundwater resources in Niger are not being overutilized and could be further developed
for beneficial use. Our estimated recharge rates compare favorably to previous estimates and provide
managers with the data required to understand how much additional water could be extracted in a
sustainable manner.
Il est attendu pour la grande saison des pluies 2022 des pays du Golfe de Guinée des quantités de pluies globalement moyennes à déficitaires, un démarrage tardif de la saison des pluies, une fin de saison à tendance normale, des séquences sèches longues après le démarrage de la saison et des écoulements à tendance globalement déficitaire ou moyenne dans les bassins côtiers.
