Aquifer potential of the transboundary crystalline-sedimentary complexes: from Northcentral Nigeria to Northwestern Cameroon border

Abstract

The aquifer system was apparently hidden but has been revealed as linked to transboundary aquifers; hence, additional info for data update of the International Groundwater Resources Assessment Center (IGRAC). The aquifer was explored for the purpose of Internationally Shared Aquifer Resource Management (ISARM). It advanced from fractured aquifers at upstream to the multilayered aquifer system toward downstream. The watershed was explored from Northcentral Nigeria to Cameroon border with electrical sounding. Geological/Hydrogeological details were locally concentrated at the center of the watershed via drilling program, aquifer tests, and hydrological modeling. Aquifer stress index (AQSI) of the region was reviewed from the existing global dataset. Results revealed aquifer provenances from crystalline and sedimentary complexes. The aquifers were relatively inferred at third and fourth geoelectrical layers at upstream and downstream, respectively. Generally, drilling operation showed depth as ≥50.0 m. Most boreholes showed drawdown of ≤5.0 m and transmissivity of ≥100 m2/day, signifying the prolific nature of the aquifer system and enormous groundwater recharge. The AQSI ≤ 0.1 signified a stress-free aquifer. Concentrations of solutes are within nutritional background, yet moderately hard with bicarbonate/carbonate concentrations that can degrade the irrigation quality. Precipitates (CaCO3) from limestone provenance may hamper borehole yields at downstream alluvium. Thus, injection of gypsum at the groundwater recharge zones is a certified remedial.