Climate change on Discharge and Sedimentation of River Awara, Nigeria

The dynamics of variation in effect of climate change on discharges and sedimentation mechanism of River Awara is investigated using 14-year data of rainfall (mm), discharges (m3/s), temperature (0c) and sediment load (t). Surface runoff (mm) was computed using Water Balance Equation and some other empirical iteration based on the observed rainfall and temperature over a period of time. Analysis of Paired Sample reveals the relationship between tested hydrological variables: Rainfall-Runoff; Runoff-Sediment load; and Discharge-Sediment load are significant at 0.95 level of confidence interval. Logarithm calibration curve further illustrates that Rainfall-Runoff and Runoff-Sediment have coefficient values (R2) of 0.996 and 0.822 respectively. Analytical iteration shows that the intensity and duration of precipitation determine the magnitude of river, generation of surface runoff and sedimentation rate. Increase in rainfall depth by 100 mm within the 14-year has resulted to serious erodobility and erositivity around River Awara. Cumulative average sediment load ratio of 0.46 has significantly reduced the reserviour capacity of the river by 10%. 78% of total annual surface runoff is lost to ocean; since reseviour capacity has been silted up which in turns reduces the volume of water that could be held for storage, treatment and distribution for its intended purposes. Comparative physics-based output indicates that temperature increase of 0.70c between 1997 and 2004, due to internal processes of the Earth and some human activities. It is however projected that temperature will rise by 0.90c by the end of 2015. Projected rise in temperature will adversely affect hydrological cycle and complicate already scarce-water resources due to intensive evapotranspiration, infiltration and reduction in stream flow. Holistic integration using bottom-up mechanism needs to be applied to address this constraint. Dredging of river awara is very important to enhance its storage capacity and planting well covered crop across the tributaries to trap sediment flow and reduce river siltation. Comprehensive adaptive measures are strongly encouraged to cope with multiple impacts of climate change in various human endeavors.