A multi-tracer approach for assessing the origin, apparent age and recharge mechanism of shallow groundwater in the Lake Nyos catchment, Northwest, Cameroon

•Compiled data to understand flow and recharge systems in the Lake Nyos catchment is provided.•The local meteoric water line of the Lake Nyos catchment has been generated.•Rapid recharge occurs under negligible effect of evaporation following rainfall.•CFCs and SF6 indicated modern waters (mean age of 25years) with short residence time.•Three main flow regimes govern groundwater movements in the Lake Nyos catchment.