Am Ayanshola

OPTIMUM PARAMETER SELECTION FOR THE MORPHOMETRIC DESCRIPTION OF WATERSHEDS: A CASE STUDY OF CENTRAL NIGERIA

Hydrological models are very useful for predictions in many ungauged basins across the world. There are many hydrological models available for discharge data generation with different complexities and varied input parameter requirements. Studies have shown that models with many input parameters do not necessarily perform better than those with few input parameters. Basin morphometric parameters play significant roles in the conversion of rainfall to runoff and obtaining good estimates of these parameters for use in runoff models is sometime challenging as Inaccurate input into models can propagate errors and make the models to perform poorly. This study employs the method of principal component analysis to reduce the number of morphometric parameters required to run a runoff model without losing any major information. Parameters for five selected study basins in central Nigeria were measured and analysed. The result shows that three morphometric parameters (Fitness Ratio, Ruggedness Number and Watershed Eccentricity) can adequately represent other parameters as an input into a runoff model for the basins. This reduces significantly the time and effort needed to compute all the parameters which in actual fact may not improve the quality or efficiency of the runoff model.

The Impact of Global Warming on Precipitation Patterns in Ilorin and the Hydrological Balance of the Awun Basin

Abstract This study presents the impact of global warming on precipitation patterns in Ilorin, Nigeria, and its implications on the hydrological balance of the Awun basin under the prevailing climate conditions. The study analyzes 39 years of rainfall and temperature data of relevant stations within the study areas. Simulated data from the Coupled Global Climate model for historical and future datasets were investigated under the A2 emission scenario. Statistical regression and a Mann-Kendall analysis were performed to determine the nature of the trends in the hydrological variables and their significance levels, while a Soil and Water Assessment Tool (SWAT) was used to estimate the water balance and derive the stream flow and yield of the Awun basin. The study revealed that while minimum and maximum temperatures in Ilorin are increasing, rainfall is generally decreasing. The assessment of the trends in the water balance parameters in the basin indicates that there is no improvement in the water yield as the population increases. This may result in major stresses to the water supply in the near future.

Evaluation of the Hydropower Generation Potential of a Dam Using Optimization Techniques: Application to Doma Dam, Nassarawa, in North Central Nigeria

Abstract Optimization models have been developed to maximize annual energy generation from the Doma dam, subject to the constraint of releases for irrigation, ecological purposes, the water supply, the maximum yield from the reservoir and reservoir storage. The model was solved with LINGO software for various mean annual inflow exceedence probabilities. Two scenarios of hydropower retrofitting were considered. Scenario 1, with the reservoir inflows at 50%, 75%, and 90% probabilities of exceedence, gives the total annual hydropower as 0.531 MW, 0.450 MW and 0.291 MW, respectively. The corresponding values for scenario 2 were 0.615 MW, 0.507 MW, and 0.346 MW respectively. The study also considered increasing the reservoir’s live storage to 32.63Mm3 by taking part of the flood storage so that the maximum draft increases to 7 Mm3. With this upper limit of storage and draft with reservoir inflows of 50%, 75% and 90% probabilities of exceedence, the hydropower generated increased to 0.609 MW, 0.540 MW, and 0.347 MW respectively for the scenario 1 arrangement, while those of scenario 2 increased to 0.699 MW, 0.579MW and 0.406 MW respectively. The results indicate that the Doma Dam is suitable for the production of hydroelectric power and that its generation potential is between 0.61 MW and 0.70 MW.