Assessment of Effects of Climate Variability on Water Resources in the Komadugu-Yobe River Basin, Yobe State

The Komadugu-Yobe River Basin in Yobe State, North East Nigeria, is one of the most water-stressed river systems in West Africa, with significant interannual variability driven by climate change and land use transformation. This study assesses the effects of climate variability on water resource availability in the Nigerian portion of the Komadugu-Yobe Basin. Monthly rainfall records from six meteorological stations within and adjacent to the basin were analysed for trends from 1990 to 2023 using the Mann-Kendall trend test. Streamflow records from three gauging stations on the Komadugu-Yobe River and its tributaries were similarly analysed. Land use change analysis was conducted using Landsat satellite imagery at five-year intervals. Results indicate a statistically significant declining trend in annual rainfall of 3.2 mm per year over the study period at four of six stations. Mean annual river flow has declined by 38 percent from the 1990 to 1999 baseline to the 2013 to 2023 period. Irrigated agricultural land has expanded by 67 percent, significantly increasing consumptive water use. Lake Chad level data confirm continued decline consistent with reduced tributary flows. The study concludes that combined climate variability and irrigation expansion are reducing available water resources at a rate threatening dry-season flows and recommends integrated water allocation management under a formal river basin authority framework.

Keywords: climate variability, water resources, Komadugu-Yobe Basin, streamflow trends, Yobe State