Temporal Assessment of River Stages and Discharge Regimes of the Cross River Basin, SE-Nigeria

Abstract Hydrological basins commonly experience variations in flow and discharge regimes which are dominantly controlled by prevalent climatic conditions as well as other hydrological parameters. This study is being carried out to establish baseline documentation of water levels and discharge regimes in the Cross River hydrological basin in southeastern Nigeria. The focus of the study is on monitoring sections of the river basin underlain by varied geology and geomorphological settings and the computation of annual means of water levels and discharge with their fluctuations for a period of five years (2010–2014). The data for daily water levels and discharge were recorded at four river gauging stations within the hydrological basin during the study period. Annual mean values for the dataset were computed to establish low and peak flows in the river basin within the period of investigation. Analysis of data by principal component analysis (PCA) shows significant positive correlations for rainfall, mean of water level, and minimum discharge in the upstream and midstream sections of the basin. The mean water level and minimum discharge in the downstream section of the basin indicate no significant correlation with rainfall. Generally, discharge increased from the upstream to the downstream of the basin, and rainfall amounts also increased within the period. Drought analysis by calculation of water-bearing coefficients shows that the basin generally experienced a dry hydrological regime in the first three years of monitoring and a wet regime in the latter years. Variations within the basin over the study period indicate the effects of location, catchment size, and other hydrological parameters.