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There is a need to develop an optimization tool that can be applied in the feasibility study of a hybrid renewable energy system to find the optimal capacity of different renewable energy resources and support the decision makers in their performance investigation. A multi-objective function which minimizes the Levelized Cost of Energy (LCOE) and Loss of Load Probability Index (LLPI) but maximizes the novel Energy Match Ratio (EMR) was formulated. Simulation-based optimization method combined with e-constraint technique was developed to solve the multi-objective optimization problem. In the study, ten-year hourly electrical load demand, using the end-use model, is estimated for the communities. The performance of the developed algorithm was evaluated and validated using Hybrid Optimization Model for Electric Renewables (HOMER ®) optimization software. T he developed algorithm minimized the LCOE by 6.27% and LLPI by 167% when compared with the values of LCOE ($ 0.444/kWh ) and LLPI ( 0.000880 ) obtained from the HOMER ® optimization tool. Also, the LCOE with the proposed approach was calculated at $0.417/kWh, which is lower than the $0.444/kWh obtained from HOMER ® . From environmental perspective, it is found that while 141,370.66 kg of CO 2 is saved in the base year, 183,206.51 kg of CO 2 is saved in the ninth year . The study concluded that the approach is computationally efficient and performed better than HOMER ® for this particular problem. The proposed approach could be adopted for carrying out feasibility studies and design of HRES for Off-Grid electrification, especially in the rural areas where access to the grid electricity is limited

The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XLIV-4/W3-2020, 2020 5th International Conference on Smart City Applications, 7–8 October 2020, Virtual Safranbolu, Turkey (online) Water shortages are a chronic and severe problem in South Africa. Allocation of this limited water resources, environmental quality, and policies for sustainable water use are issues of increasing concern that require accurate and timely information to evolve strategies for dynamic natural resources management. Specifically, this paper is aimed to assist the planning, restoring and to rationally allocate the water resources in any river basin in resolving the current water stresses in many parts of South Africa, by using integrated knowledge from simulation and integrated river basin management approach. The developed system dynamic (SD) allocation system was used to investigates the extent to which the framework is ‘sustainable’ in the medium and long terms in evaluating existing and future water allocation among conflicting users at Mkomazi River Basin (MRB), KwaZulu-Natal Province, South Africa The invented SD framework confirms agricultural water use as the highest demand when compared with other users. The optimal sustainability performance index (0.25) of the system at 70% dependable flow shows an integrated scenario that combines rainfall variation with improved irrigation water use efficiency as a suitable framework plan. The study uses integrated knowledge from simulation and integrated river basin management approach as a feasible method to assist the planning, restoring and to rationally allocate the water resources in any river basin with similar attributes to the study area in resolving the current water stresses in many parts of the country. Water resources managers would find these tools beneficial in understanding the complex nature of water resources allocation and in determining priorities area which required prompt attention and intervention

Reservoir sedimentation has been a major concern to stakeholders around the world in the implementation of sustainable management of hydropower dams. Not only that it reduces the storage capacity of reservoirs, several sediment related problems such as reduction in water quality and acceleration of abrasion of underwater parts can impair the primary purpose of which the reservoir is built. Therefore, sustainable management of watersheds upstream of hydropower dam is necessary to combat the issues of sedimentation and to extend its useful life. In this study, Soil and Water Assessment Tool (SWAT) was interfaced with MapwindowGIS to model and predict sediment yield and concentration into sub-basins of the upper watershed of Kainji hydropower dam in Nigeria which has an area of 30,350 km2. The model was run daily for 30 years and performance evaluation was carried out using Coefficient of Determination (R2) and Nash Sutcliffe Efficiency (NSE). Model calibration and validation as well as identification of erosion prone areas were equally achieved. The results showed that average annual sediment yield and concentration were 35.29 t/ha/year and 11,903.7 mg/l respectively. Application of filter strips on critical erosion prone region showed that sediment yield and concentration could be reduced up to 37% and 34% respectively. Also, construction of stone bunds in the watershed showed a reduction of up to 75% and 84% for sediment yield and concentration respectively. The outcome of this study could allow control effort to be focused effectively on an area identified as extreme cases and could also be used by relevant authorities in prioritizing implementation of Best Management Practices (BMPs) for the area.

Nigeria's Jebba sub-basins are synonymous to frequent flooding, high rate of erosion, depletion of soil nutrients and unsustainable water use. The uncontrolled flooding may be a result of numerous factors related to topography, geology, climate and human activity. The present work was an attempt to describe the application of Geographical Information System (GIS) and Digital Elevation Model (DEM) for the estimation of morphometric characteristics of eight sub-basins in the upstream watershed of Jebba reservoir, Nigeria. Morphometric characteristics such as topographic, areal, relief and network were determined. Soil Conservation Service (SCS) technique was applied to estimate hydrographs. The study revealed that sub-basin number 3 had the lowest time of concentration and maximum depth of runoff while sub-basin number 2 had maximum ratio of circulation of 1.8 and it is tagged as the area that is highly prone to flood. The peak runoff in the sub-basins ranged between 330.10 and 924.86 m3/s (25-year return period) and for 100-year intervals ranged between 502.69 to 1408.40 m3/s. The estimated peak runoffs can be adopted for designing and constructing erosion control structures in the catchment area.

The management of water resources for different purposes such as a domestic water supply and municipal, irrigation and hydropower generation requires optimization techniques for efficient reservoir operations. This study focused on the optimization of energy generation at Kainji hydropower station in Nigeria using operational and ecological integrity constraints. A linear optimization technique was used in optimizing the average total annual energy generation subject to operational and ecological integrity constraints. The model was solved using LINGO 17.0 software. The results revealed that the optimization approach would increase the total annual energy generation at the hydropower station by 1.84%. The outcome of this study can be adopted by the management of a hydropower station and other decision makers in Nigeria to improve the availability of electricity deployed to Nigeria’s national grid without compromising the ecological integrity of a reservoir.

Noise from transportation systems is unavoidable in urban areas and can be harmful to human health. The noise generated by selected transportations systems in Ilorin, an urban area in central Nigeria, was studied by direct measurements and the use of questionnaires. Measurements were taken at the airport, train station and different locations for vehicular traffic. Questionnaires were also administered on residents of these areas to elicit information on the perception of transportation noise in the areas. The results show that all the studied locations produced maximum noise levels in excess of the 85-dBA acceptable tolerable limit for humans. The train station produced the highest stepwise noise levels due to the motion and horning of the locomotive engines. The study also established distances in which the sound level is safe over a specific period of time for each of the studied noise sources. These are of 18.84 m, 161.21 m, 13.85 m and 15.08 m for aircraft take-off, movement and horning of railway locomotive engine and vehicular traffic inside and outside town respectively. Suggested solutions were that residential buildings, academic areas and hospitals should not be located too close to sources of transportation noise and the need for enforcement of relevant noise control laws is to be pursued. Keywords: Noise pollution, sound pressure level, equivalent sound level, acceptable noise level, noise perception

BackgroundThe interest in larvicides of plant origin is generally renewed in vector control because of their safety compared to synthetic larvicides. However, there are concerns about the relative safety dose of these phytochemicals on non-target organisms which led to the development of plant derived nanoparticles. In this study, we examined the bioefficacy of low doses of two green synthesized nanoparticles on immature stages ofAnophelesmosquitoes in Nigeria. Aqueous plants (Moringa oleiferaandFicus exasperata) extracts were used in the biosynthesis. The prepared Ag-NPs were characterizations using Fourier-transform infrared spectroscopy (FT-IR), UV-Vis spectroscopy, and scanning electron microscopy (SEM). Third and early fourth instars of known susceptible laboratory strains ofAnopheles gambiae s.s.(KISUMU strains) and pyrethroid resistant field strain ofAn. gambiaewere exposed to serial dilutions of 0.25, 0.5, 0.75, 1.0 and 2.5 ppm of each phyto nanoparticles. Moribund and dead larvae were observed after 24 and 48 h post exposure, and the results were analysed with descriptive statistics.ResultsWith the laboratory mosquitoes,Moringa oleiferaAgNP effected high mortalities of 88–100% (LC50 = 0.39 ppm; LC95 = 0.62 ppm) at 24 h post exposure except at the lowest concentration, whileFicus exasperateAgNP induced a 32–100% mortality (LC50 = 0.51 ppm; LC95 = 1.15 ppm) except at the lowest concentration. In the field populations, mortality inMoringa oleiferaandFicus exasperatawas 23–93% (LC50 = 0.65 ppm; LC95 = 2.28 ppm) and 37–50% (LC50 = 1.51 ppm; LC95 = 391.64 ppm) respectively. There was no significant difference in mortality values between the laboratory and field strains (P ConclusionsOverall, the study demonstrates the bioefficacy and potential use of green synthesized nanoparticles, at very low concentrations for the control ofAnopheleslarvae even in areas where resistance to the current chemical insecticides have been reported.

Water allocation planning in an equitable and sustainable way is intrinsically complex. This study proposes a water resource allocation system using an integrated Soil and Water Assessment Tool and Water Evaluation and Planning tool (SWAT-WEAP) model for hydrological simulation and prognostic scenarios sustainability prediction. The study explores the use of Digital Elevation Model (DEM), soil and land raster image in deriving physiographic information for land degradation impact assessment, quantification of optimal water allocation and generation of minimum ecosystem water requirement. Consequently, the SWAT quantifies the catchment water yield before been allocated optimally based on percentage dependable flow rates of 70% and 85% reliability flow regime at Makurdi, Nigeria discharge station. The WEAP model assesses the water resources utilization following scenarios adaptation by riparian users. Both models performed satisfactorily for streamflow and water yield prediction and resource sharing both in the calibration and validation phases with a correlation coefficient (R2) of 0.57–0.74 and root squared error (RSR) of 0.66–0.82. The results show how drainage network, channel length, drainage boundary, slope, and sub-catchment geometric properties demonstrate Geographic Information Systems (GIS) utility in morphoclimatic impacts assessment as a data management, scenario analysis, and decision support tool in water management for the Lower Benue River Basin, Nigeria. Planners and decision-makers need to consider several integrated plans as alternatives to adapting to climate change impacts and anthropogenic human activities in resolving the unmet demands.

Water allocation management in an equitable and sustainable way is intrinsically complex. Climate change and managerial policy have further adversely altered the hydrologic cycles thus, threatens to worsen the current supply-demand imbalance. This study was conducted in Lower Benue River Catchment in the North Central crevice of Nigeria, to assess the consequences of climate change due to changing rainfall patterns in the area and proposes different prognostic scenarios adaptation on the current and future water allocation sharing in the area. The Soil and Water Assessment Tool (SWAT) was interfaced with Map window - Geographic Information Systems (GIS) for the basin hydrological modeling to assess the impact of the watershed characteristics on runoff and subsequent quantification of the catchment water yield before been allocated optimally based on percentage dependable flow rates of 70% and 85% reliability flow regime at Makurdi, Nigeria discharge station. Furthermore, the Water Evaluation and Planning tool (WEAP) model was used for the water resources utilization simulation and adaptation scenarios by the different riparian users. The SWAT model performed satisfactorily for streamflow and water yield prediction both in the calibration and validation phases with a R2 of 0.57-0.68 and RSR of 0.66-0.82, while the WEAP model calibration and validation at the same station with rainfall data posted a R2 of 0.64 and 0.89. Planners and decision-makers on water resources allocation, therefore, need to consider several integrated plans as alternatives to the adaptation to climate change impacts and anthropogenic activities in resolving the unmet demands.

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.

Hydropower dams are one of the many kinds of modifications that human beings make to natural waterways, but they can have especially profound ramifications for riverine ecosystems and the animals that live in them. The operation of hydropower reservoirs in Nigeria does not take into cognizance the ecological situation of the reservoir as it may affect aquatic life that depend on it. This study is sought to model energy generation at Kainji hydropower reservoir, Nigeria considering ecological flow release (EFR) scenarios. Two neural network (NN) approaches were used to optimize the energy generation at the station using the current operating rule and incorporation of EFR scenarios. The study revealed that the correlation coefficients (r) for energy generation without considering EFR using multilayer perceptron neural network (MLPNN) and radial basis neural network (RBFNN) were 0.94 and 0.84, respectively. Average annual energy generation at the station using MLPNN and RBFNN approaches, without considering EFR were 223930 and 222926 MWh, respectively. The two NN modeling approaches were found to perform well in simulating energy generation. The appropriate reservoir operation rule stipulated that the EFR that will not negatively affect energy generation should range between 10 to 25% of reservoir storage.

This study utilized Spatial Information Technology (SIT) such as Remote Sensing (RS), a Geographical Information System (GIS), the Global Positioning System (GPS) and a high-resolution Digital Elevation Model (DEM) for a morphometrical analysis of five sub-basins within the Lower Niger River Basin, Nigeria. Morpho-metrical parameters, such as the total relief, relative relief, relief ratio, ruggedness number, texture ratio, elongation ratio, circularity ratio, form factor ratio, drainage density, stream frequency, sinuosity factor and bifurcation ratio, have been computed and analyzed. The study revealed that the contribution of the morphometric parameters to flooding suggest catchment No. 1 has the least concentration time and the highest runoff depth. Catchment No. 4 has the highest circularity ratio (0.35) as the most hazardous site where floods could reach a great volume over a small area.

This study is focused on the application of Genetic Algorithm (GA) as an effective tool for modeling the operation of a multi-purpose reservoir with specific emphasis on Jebba Hydropower Dam, Nigeria. The specific objectives are to study the reservoir operation rule; model the reservoir parameters such as inflow, elevation, turbine release, generating head, energy generation, tailrace water level and plant coefficient. Available Data for 27-year period (1984–2011) was obtained from the Dam Station for statistical analysis. MATLab software for GA was used, and for comparison and check, another similar optimization software (LINGO) was utilized. The optimal solution obtained at operating performance of 50% reservoir inflow reliability has total annual energy generation of 42,105.63MWH. GA for the total annual energy generation at operation performance of 95, 90 and 75% reservoir inflow reliability are 15,964.48 MWH, 21,009.53 MWH and 20,798.58 MWH, respectively. The application of GA will lead to a more realistic and reliable optimal value for the improvement of hydroelectric power generation and flood management, which would guide decision makers in the hydropower sector.

This paper presents the evaluation of the impact of climate change on water resources and yield capacity of Asa and Kampe reservoirs. Trend analysis of mean temperature, runoff, rainfall and evapotranspiration was carried out using Mann Kendall and Sen’s slope, while runoff was modeled as a function of temperature, rainfall and evapotranspiration using Artificial Neural Networks (ANN). Rainfall and runoff exhibited positive trends at the two dam sites and their upstream while forecasted ten-year runoff displayed increasing positive trend which indicates high reservoir inflow. The reservoir yield capacity estimated with the ANN forecasted runoff was higher by about 38% and 17% compared to that obtained with historical runoff at Asa and Kampe respectively. This is an indication that there is tendency for water resources of the reservoir to increase and thus more water will be available for water supply and irrigation to ensure food security.

In this study, probability analysis was performed on peak daily rainfall data in order to predict rainfall interval values and to determine the best fit functions in some parts of Nigeria. The selected towns are Kaduna, Kano, Yola, Jos, Damaturu and Maiduguri. The obtained peak daily rainfall values were subjected to Gumbel, Log-Gumbel, Normal, Log-Normal, Pearson and Log-Pearson probability distributions. Mathematical equation for probability distribution functions were established for each town and used to predict peak rainfall. The predicted values were subjected to goodness of fit tests such as Chi-square, Correlation Coefficient, Coefficient of Determination and Errors of Estimates to determine how best the fits are. The model that satisfies the tests adequately was selected as the best fit model. The study revealed that the peak rainfall at Kaduna, Jos, Kano, Yola and Damaturu are best fitted by log-Gumbel, while log- Pearson distribution is suitable for predicting peak rainfall in Maiduguri. The result also shows that the occurrences of peak daily rainfall depth of 100 mm and above are rare in the selected areas. Keywords: Peak rainfall, Probability distribution models, Return period, Probability interval and goodness of fit tests

Our study revealed periodicities of 2.3 and 2.25 years in wet and dry seasons and periodicities of 2 to 5 years on seasonal and annual timescales. Minimum temperature (Tmin), maximum temperature (Tmax) and evaporation recorded increases of 2.47, 1.37 and 28.37 %, respectively, but a reduction of 19.58 % in rainfall on decadal timescale. Periodicity of 8 to 12 years was also observed in annual Tmax. Cramer’s test indicated a warming trend with significant Tmax increase in February, April, July, August, October and November during 2000–2009 on decadal monthly timescale, a significant decline in Summer rainfall but significant Tmax increase in Spring, Autumn and Winter on decadal seasonal timescale. The low correlation of rainfall with temperature parameters and evaporation indicates that advection of moisture into Lagos State seems to be the dominant mechanism controlling rainfall within the State alongside other tropical and extra-tropical factors. In addition, our study revealed that the persistent state of minimum temperature often precedes the arrival and reversal of the phase of maximum temperature. Furthermore, our study also revealed that extreme and high variable rainfalls, which are associated with the increased warming trend, had periodicities of 1 to 3 years with a probability of 86.45 % of occurring every 3 years between April and September. It is recommended that government and private sector should give financial and technical supports to climate researches in order to appropriately inform policy making to improve the adaptive capacity and resilience of Lagos State against climate change impacts and guard against maladaptation.

This paper presents the evaluation of methods of determination of peak runoff for an ungauged catchment. The present study made use of Geographical Information System (GIS) for the morphometric analysis of four sub-catchments within Jere sub-basin in Gurara Basin, Nigeria. Various morphometric parameters were computed and analyzed as sub-basin characteristics are important factors in determining the runoff. Three methods of peak runoff estimation were used to determine peak runoff of the study area for four return periods. The results of the peak runoff estimation based on rational method for the four sub-catchments for 25-year, 50-year, 75-year and 100-year return periods varied between 224m3/s and 1036m3/s, while the results for the SCS method varied between 105.3m3/s and 162.05m3/s and the results from the Cypress Creek method varied between 22.8m3/s and 86.55m3/s. The results obtained from the three methods showed that there are significant differences in the peak runoff results and also there are significant differences in the peak runoff results for the different return periods.

Small hydropower has been found to have a positive effect on the quality of life of rural dwellers in numerous ways. It provides a wide range of services, such as improved lighting; energy for small industries, schools, computer and communication service centers, clinics, and entertainment centers; and operations of a range of domestic and light industrial appliances. Nigeria has many dams built for irrigation and water supply, but these may still have the potential for other uses. One such dam is the Doma dam in north central Nigeria. The dam has a live storage of 30 Mm3 and a yearly average inflow of 114 Mm3. This study is a hydrological investigation concerning the possibility of using the dam for power generation. An artificial neural network model, as automated in ALYUDA Forecaster XL, was used to extend the available streamflow record at the dam site. Thereafter, a reservoir yield–capacity analysis was carried out by maximizing the unknown releases subject to storage capacity constraints. The sequent peak algorithm was used to establish the real storage needed to meet the primary demands, including ecological releases and evaporation losses. The results showed that the maximum monthly yield from the reservoir is 6.56 Mm3, while the storage required to satisfy the dam’s primary functions is 12.07 Mm3. This means that there is 16.93 Mm3 of monthly excess stored water, or 6.53 m3/s, which can be used for other purposes, such as electricity generation. Considering 50%, 75%, and 100% usage of the excess stored water with a head of 20 m, the power potentials were found to be 0.51 MW, 0.77 MW, and 1.03 MW, respectively. It is expected that providing 2×500 kW Kaplan turbines to operate for 12 hours a day will deliver between 2.0 and 4.0 GWh of energy yearly to the immediate communities in the Doma local government area.

This paper presents the development of unit and storm hydrographs for Rivers Moro, Asa and Oyun catchment. Snyder's method was used to develop the unit hydrographs; while the SCS Curve Number method was used to estimate excess rainfall values from rainfall depth of different return periods. The design storm hydrographs corresponding to.the excess rainfall values were determined based on the unit hydrograph ordinates established through convolution. The design storm hydrograph obtain~d for Moro River catchment based on 5-yr, 20~yr~ 50-yr, 100-yr and 200-yr return period ranged between 245.29m3/s and 685.84m3/s. That of Asa River catchment varied from 301.34m3/s to 846.46m3/s and the design storm hydrograph flows obtained for Oyun River catchment varied from 257 .29m3/s to 723.56m3/s. The design storm hydrograph flows obtained can be recommended for sizing hydraulic structures within Kwara State drainage network.Keywords: Unit hydrograph, stonn hydrograph, storm duration, River catchment and recurrence interval

No Abstract

Estimation of water yield and water balance in a river catchment is critical to the sustainable management of water resources at watershed level in any country. Therefore, in the present study, Soil and Water Assessment Tool (SWAT) interfaced with Geographical Information System (GIS) was applied as a tool to predict water balance and water yield of a catchment area in Nigeria. The catchment area, which was 12,992km2, is located upstream Jebba hydropower dam in North central part of Nigeria. In this study, data on the observed flow were collected and compared with simulated flow using SWAT. The correlation between the two data sets was evaluated using statistical measures, such as, Nasch-Sucliffe Efficiency (NSE) and coefficient of determination (R2). The model output shows a good agreement between the observed flow and simulated flow as indicated by NSE and R2, which were greater than 0.7 for both calibration and validation period. A total of 42,733 mm of water was predicted by the calibrated model as the water yield potential of the basin for a simulation period between 1985 to 2010. This interesting performance obtained with SWAT model suggests that SWAT model could be a promising tool to predict water balance and water yield in sustainable management of water resources. In addition, SWAT could be applied to other water resources in other basins in Nigeria as a decision support tool for sustainable water management in Nigeria., {"references":["A. Fadil, H. Rhinane, A. Kaoukaya, Y. Kharchaf, and O. A. Bachir. \"Hydrologic Modeling of the Bouregreg Watershed (Morocco) Using GIS and SWAT Model\" Journal of Geographic Information System vol 3, 2011, pp279-289","N. K. Shrestha, P. C Shakti, P. Gurung \"Calibration and Validation of SWAT Model for Low Lying Watersheds: A Case Study on the Kliene Nete Watershed\", Belgium. HYDRO Nepal Volume 1,2010, pp 47-51","N. Omani, M. Tajrishy and A. Abrishamchi \"Modeling of a River Basin Using SWAT Model and SUFI-2\". 4th International Conference of SWAT Model UNESCO-IHE Delft, Netherlands July 4-6 2007","S. L Neitsch, J. G Arnold, J. R Kiniry, J. R Williams \"Soil and Water Assessment Tool Theoretical Documentation Version 2005. Grassland, Soil and Water Research Laboratory, Agricultural Research Service 808 East Blackland Road, Temple, Texas 76502;Blackland Research Centre, Texas Agricultural Experiment Station 720,East Blackland, Texas USA","Hydrological Report and Documentation 2012, Jebba Hydro Electric Power Authority, Jebba, Nigeria ( unpublished)","J. G. Arnold, J. R. Williams and D. R. Maidme \"Continuous-time water and sediment-routing model for large basins\". Journal of Hydraulic Engineering, Vol.121, No 2, 1995 pp 171-183.","L. F. 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Romero and H. Alcayaga \"Hydrological modelling with SWAT under conditions of limited data availability: evaluation of results from a Chilean case study\" Hydrological Sciences–Journal–des Sciences Hydrolgiques, Vol.53,Number 3, 2008,pp 588-601.\n[14]\tD. N. Moriasi, J. G Arnold, M. W. Van Liew, R. L Bingner, Harmel, R. D., and T. L. Veith, \"Model evaluation guidelines for systematic quantification of accuracy in watershed simulations\", T. ASABE, Vol 50,2007 pp 885–900.\n[15]\tS. K. Jain, J. Tyagi and V. Singh. \"Simulation of Runoff and Sediment Yield for a Himalayan Watershed Using SWAT Model\". Water Resources and Protection Volume 2, 2010, pp267-281.\n[16]\tJ. G. Arnold, J. R. Kiniry, R. Srinivasan, J. R. Williams, E. B. Haney, and S. L. Neitsch \"Soil and Water Assessment Tool Input Output File Documentation\". Soil and Water Research Laboratory, Agricultural Research Service, Grassland, 808 East Black land Road, Temple, Texas 2011.\n[17]\tJ. G. Arnold, D. N. Moriasi, P. W. 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This paper presents the application of Mann-Kendall trend test and Standard Anomaly index onhydro-meteorological variables in the coastal area of Lagos state in order to determine the nature of trend and level of significance. The hydro-meteorological data such as air temperature, relative humidity, wind speed, rainfall and sea level rise were obtained from Nigeria meteorological agency (NIMET) Oshodi, Lagos. Variables such as rainfall, relative humidity, wind speed and sea level rise exhibited positive Kendall’s (S) values indicate upward trend and imply an increase of the parameters over time. However, temperature showed negative Kendall’s (S) which indicates downward trend and implies decrease over time. Sea level rise, rainfall, relative humidity and wind speed has mean statistics Zs of 3.9855, 1.9668, 3.0895 and 2.2553 respectively which are more than 1.96 (test statistics for a significant level of 5% that is (Z 0.025 =1.96), this implies that the upward trend is significance and there is tendency to continue. Temperature has statistic Zs of 0.0309 which is less than 1.96 and implies no significance, thus the reduction may not be noticed. The auto correlation factor values ranges from 0.59 to 0.99 for all the parameters, indicating a good fit. Standard Anomaly index (SIA) results showed that trends for the temperature depicts downward trend with the slope of the trend equations are negative, this implies that temperature has tendency to decrease. Rainfall, relative humidity and sea level rise exhibited upward trend which implies tendency to increase. However, the mean wind speed exhibited upward trend while both maximum and minimum wind speed exhibited downward trend, but not noticeable. It can be inferred that both Mann-Kendall trend test and standard anomaly index showed that there is tendency for trend increase in rainfall, humidity, windspeed and sea level rise, while temperature has tendency to decrease. This could be due to impact of climate variability which can influence flooding pattern in the coastline of Lagos State. Keywords: Climate variables, Mann-Kendall test, Standard Anomaly index, hydro-Meteorological variables, Lagos coast

This study focused on the evaluation of willingness-to-pay (WTP) for sustainable household water use in Ilorin, Nigeria. The study involved assessment of the existing water supply situation particularly considering water use indicators such as demography, adequacy of existing water supply system and WTP for reliable supply. Field work involved the use of structured questionnaire to obtain data on household water use and WTP for a reliable water supply of the sampled houses consisting three land use patterns. Stata/SE 8.0 and Microsoft EXCEL software were employed to evaluate the variables that affect WTP for improved household water use while ccontingency Valuation Method was adopted to evaluate the WTP for reliable and sustainable service delivery. The findings of the study revealed that: approximately 70 % of total sampled households were connected to municipal supply out of which 13 % indicated satisfaction in terms of sufficiency and 87 % used alternative sources to augment water supply; consumers are willing to pay an average sum of N 737.22 per month for improved water supply services and; gender, water quality and household income level have significant impact on WTP at 5% level of significance. There is the need to put in place a framework to enhance improvement of system reliability and sustainability. Keywords : Evaluation, willingness, reliability, sustainability, household, water

Efficient management of hydropower reservoir can only be realized when there is sufficient understanding of interactions existing between reservoir variables and energy generation. Reservoir inflow, storage, reservoir elevation, turbine release, net generating had, plant use coefficient, tail race level and evaporation losses are the major hydropower reservoir variables affecting the energy generation. Thus, this paper presents the modelling of reservoir variables of two hydropower dams along the River Niger (Kainji and Jebba dams) in Nigeria for energy generation using multilayer perceptron neural network. Total monthly historical data of Kainji and Jebba hydropower reservoirs’ variables and energy generated were collected from Power Holding Company of Nigeria respectively for a period of (1970-2011) and (1984-2011) for the network training. These data were divided into training, testing and holdout data set. The neural network summary yielded a good forecast for Kainji and Jebba hydropower reservoirs with correlation coefficients of 0.89 and 0.77 respectively. These values of the correlation coefficient showed that the networks are reliable for modeling energy generation as a function of reservoir variables for future energy prediction. Key words: Hydropower, reservoir variables, neural network, energy generation, coefficient of correlation

Generic factors (weather, environment, vehicles, fixed roadway characteristics, pedestrian and traffic streams) singly or jointly influence the free flow speed. This paper, therefore, presents the outcome of the quantitative evaluation of the influence of these factors on the free flow speed on an arterial in a medium-sized urban settlement in Nigeria. Instantaneous speeds of forty test vehicles were observed at lull periods on the 7.1km-Offa Garage-Emir’s Road, Ilorin, with simultaneous collection of data on drivers’ and vehicle ages, passenger occupancy, roadside parked vehicles and businesses. The geometric properties of the arterial were earlier established and segmented to four uniform sections. Result of computations using the category and statistical analysis show that the environment, pedestrian and roadway geometry have negative influences on the free flow speed. This can be confirmed by the poor relationship between free flow speed and these factors, with R 2 values of 14.9-55%, and lower average free flow speed of commercial saloon cars on wet pavement than on dry pavement, with 12% percentage reduction. Adoption of design and analysis of traffic stream in Ilorin and other urban settlements in Nigeria is, therefore, recommended. http://dx.doi.org/10.4314/njt.v35i3.2

Over more than five decades, the energy sector in Nigeria, particularly the rural energy sector, is characterized by lack of access, low purchasing power and over-dependence on traditional fuels for meeting basic energy needs. In an attempt by the government to solving this challenge, the hydropower scheme came on stream as the forerunner in 1968, 1986 and 1990 at Kainji, Jebba and Shiroro respectively. The objective was to improve access to reliable, secure, affordable, climate friendly and sustainable energy services and to boost investment in energy in Nigeria. However, this solution seems to be characterized with some challenges at the downstream sector of the hydropower dams. The communities in the flood plains experience annual flooding when the authorities of Power Holding Company of Nigeria (PHCN) open the gates of the dams to let off water at the peak of the rains. The floods have caused damages and untold hardships to lives and properties. The occurrence of flood has great effect on communities and farming activities downstream of Jebba and Shiroro dams.

This paper presents the required improvement on the performance of canal network and method of on-farm water application systems at Tunga-Kawo irrigation scheme, Wushishi, Niger state. The problems of poor delivery of water to the farmland were identified to include erosion of canal embarkment, lack of water regulating structures along the secondary canals and some parts of the irrigable farmland are not leveled thereby making the farmland higher than the canal full supply level. The suggested solution include the alignment of the affected part of the secondary canal, the use of check gates structures for controlling the water level, modification of the longitudinal slope(s) of the main canal and that of the secondary canals to increase the canal conveyance capacity. The use of siphon tubes is also suggested for lifting water from the distributary channels to the irrigating farmland to minimize water loss to percolation. The uncontrolled flooding method of irrigation in use, leads to wastage of water. The pounding basin irrigation method is suggested for rice cultivation on the farm and the irrigation schedule was established to be six days. JARD Vol. 3 2004: pp. 7-20

This paper reports the evaluation of households’ usage of the current solid waste management system (SWMS) within the city of Ilorin, central Nigeria and investigates the determinants of household’s willingness-to-Pay (WTP) for its improvement. Data was collected with the aid of a structured questionnaire administered to households within four neighbourhoods that represent the major subdivisions in the metropolis. The multiple regression model was applied in explaining household’s usage of the current system and WTP.The study found that 36% and 64% respectively of the households were unsatisfied and moderately satisfied with the current waste management system. The combined effect of household’s demographic profiles, geometric profile and position of waste management facility gave a significant fitted model to show the relationship between household’s willingness to pay and the considered predictors. http://dx.doi.org/10.4314/njt.v34i4.28

The stream flow at the three hydropower reservoirs in Nigeria were modeled using hydro-meteorological parameters and Artificial Neural Network (ANN). The model revealed positive relationship between the observed and the modeled reservoir inflow with values of correlation coefficient of 0.57, 0.84 and 0.92 for Kainji, Jebba and Shiroro hydropower reservoir respectively. The established model was used to predict 20 years stream-flow for each of the hydropower reservoirs which were found to have similar statistics with the observed values. The predicted reservoir inflow were subjected to trend analysis which revealed an upward trend with percentage increase of 4.58%, 6.34% and 5.42% for Kainji, Jebba and Shiroro hydropower reservoirs respectively. The upward trend is an indication of increase in water availability for hydropower generation at the three stations given other constraints are brought under control. http://dx.doi.org/10.4314/njt.v34i1.4

In this study, a calibrated hydrologic model, Soil and Water Assessment Tool (SWAT) interfaced with Geographical Information System (GIS) tool was used to study the effect of different sediment management methods in a watershed (12,992 km2) upstream of Jebba Lake, Nigeria. Sediment management strategies considered are (i) reforestation of the watershed, (ii) application of vegetative filter strip (VFS) and (iii) construction of stone bunds. Cost analysis of implementing the selected erosion control measures within the watershed was also carried out to compare the cost effectiveness of each of the management strategies. The results showed that application of VFS, reforestation, and stone bunds to critical zones of the watershed reduced the sediment yield up to 65.6%, 63.4% and 12% respectively while the financial analysis of implementing reforestation, VFS and stone bunds revealed 84.9%, 73.3% and 70.5% reduction respectively in the costs to be incurred if sediments are allowed to accumulate in the dam. From this analysis, it can be concluded that the sediment management scenarios considered in this study are cost effective and sustainable when compared with the costs incurred in tackling the effect due to reservoir sedimentation. Overall, the study showed that hydrological models such as SWAT can be used to study strategies for water resource management. In addition, it can provide policy makers the decision support tools to evaluate the cost and benefits of adopting Best Management Practices (BMPs) particularly for sediment control in erosion prone watersheds. Keywords: Cost analysis, Jebba Reservoir, Sediment management, SWAT, Watershed