Impact of Climate Variability and Land Cover Dynamics on Groundwater Potential of Upper Benue River Basin, Nigeria

Abstract

The study assessed the effects of climate variability (precipitation and temperature) and landcover changes on groundwater potentials of the Upper Benue River Basin in Nigeria. The study involved the use of remotely sensed data with the application of Geographic Information System (GIS). It was based on survey design and both primary and secondary data were used. The study was anchored on the concept of hydrological cycle. The analytical hierarchy process (AHP) was employed in the analysis of groundwater potential of the study area. The results of this study revealed that climate variability (temperature and precipitation) and landuse/landcover both have
strong positive effect on groundwater potential in the Upper Benue River Basin. That is, when precipitation increases, the depth to abstract groundwater reduces, however, when the precipitation decreases, the depth of ground water (GW) increases. The findings of the study reveal that by 2070, the mean depth to ground water will increase from the current level (2021) of 48.9m to 65m; which is an addition of 6.1m. Furthermore, there was a loss of 15.4 % in the vegetation cover over the period while the built-up area and rock outcrop revealed significant gains of 15.2% and 2.9% respectively. The areal coverage of various GWP levels reveals that a larger portion of the basin has low GWP with an area of 44,822.4 Km2, while the poor GWP area was 43,315.7 Km2, the area covered by moderate GWP was 25,863.8 Km2 as the areas of high potential covered 11,550.9Km2. Vegetation monitoring of the basin should be mainstreamed into existing laws establishing the UBRBA to prevent further degradation as this study established a decrease in the vegetation of the basin. Afforestation of the basin is of urgent importance to help more water infiltration into the basin and sustain the ground water recharge and potential in the future.