Selection of an Appropriate Interpolation Method for Rainfall Data In Central Nigeria

Interpolation technique can be used to establish the rainfall data at the location of interest from available data. There are many interpolation methods in use with various limitations and likelihood of errors. This study applied five interpolation methods to existing rainfall data in central Nigeria to determine the most appropriate method that returned the best prediction of rainfall at an ungauged site. The methods include the inverse distance wieight method and four variants of universal kriging (spherical,exponential,gaussian and power). The Guassian model of Kriging yielded the least root mean square error for monthly rainfall interpolation and is therefore recommended for use on monthly rainfall data in Nigeria.Key Words: Rainfall, Boxplots, Kriging, Interpolation,Variograms, Gaussia

Electrical Load Survey and Forecast for a Decentralized Hybrid Power System at Elebu, Kwara State, Nigeria

This paper presents electrical load survey and forecast for a typical off-grid rural decentralized hybrid power generating systems of a rural area (Elebu). With the data available, energy demand and forecast for ten years was estimated. It was also observed that this community has potential for small hydro, wind and solar energy which can be integrated to meet the present and future energy needs of this area in a cost effective and sustainable manner. The paper reports the results of electrical load demand and forecast for Elebu rural community located in Kwara State, Nigeria. The expected peak load in first year of operation was estimated as 40.18kW which will increase every year. The maximum estimated demand at the end of tenth year is about 57 kW. This simply means that the installed capacity would not have been 57kW if the maximum estimated demand is 57kW. On the eleventh year, the demand would have exceeded the installed capacity, thereby making the system unstable and unreliable.http://dx.doi.org/10.4314/njt.v34i3.2

Regional Scale Assessment of the Gross Hydrokinetic Energy Potentials of Some Rivers in Lower Niger River Basin, Nigeria

This study investigates the hydrokinetic energy potential of some selected rivers in the Lower Niger River Basin in North Central Nigeria. The methodology adopted was to obtain the gross naturally occurring theoretical hydrokinetic potential of the rivers through the use of a hydrological model and a spatial tool. MWSWAT, an open source interface to SWAT using the GIS system MapWindow, was employed for simulation to determine the hydrological parameters of the sub-basins and other computations were done using a spreadsheet package to estimate the instantaneous power density along the river reach. Preliminary results show there are naturally occurring potentials of this technology in the Lower Niger River Basin. The estimate of the theoretical resource for the watershed totals 826.7MW (7.247TWh/yr). River Moshi has the highest discharge (8315.78 m3/secs), while Oshin has the lowest (1224.27 m3/secs). Also, Awun has the highest theoretical hydrokinetic potential of 257.5MW while Oshin has the lowest (20.9MW).http://dx.doi.org/10.4314/njt.v34i2.29

Hydrokinetic Energy Conversion Systems: Prospects and Challenges in Nigerian Hydrological Setting

Hydrokinetic energy conversion systems utilize the kinetic energy of flowing water bodies with little or no head to generate other useable forms of energy. In the last few years various research and development efforts have been made to bring out this technology from the proof of concept stage and to demonstrate its technical feasibility and potential to be deployed for the supply of stand- alone/off-grid electric power production. Being also a variant of the small hydropower scheme, which are usually site specific, much of the studies done on the technology are suited to specific sites and the peculiar hydrology of those localities. This paper, thus, explores this new emerging technology and its prospects, potentials, challenges and frameworks for its adaptation in Nigerian hydrological setting

Evaluation of Willingness to Pay for Reliable and Sustainable household Water Use in Ilorin, Nigeria

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 N737.22 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, wate

A GIS-Based Optimization Technique for Spatial Location of Municipal Waste Bins in a Developing City

Prime spatial features such as environmental constraints and indigenous transit routes which determine optimal waste bin locations in developing areas are often neglected. In this study, we illustrate a technique that includes these features to determine the optimal locations of waste bins for case study in Ilorin, Nigeria. The built-in solver for p-median problems in the Geographic information system (GIS)-based package; TransCAD v. 5.0 was used to determine the optimal locations of one to ten waste bins. This optimization technique requires less computational time and the output of ten computer runs showed that partial service coverage was obtained when p=1 to 5 while full service coverage was achieved with p≥6. Also the GIS optimized waste bin locations tend to be more accessible to waste generators than the empirical waste bin locations. Hence, this technique has the potential to improve service coverage and public satisfaction in developing areas.Keywords: Municipal solid waste; Geographic information system; waste bin; optimal location; developing city

Global patient outcomes after elective surgery: prospective cohort study in 27 low-, middle- and high-income countries.

BACKGROUND: As global initiatives increase patient access to surgical treatments, there remains a need to understand the adverse effects of surgery and define appropriate levels of perioperative care. METHODS: We designed a prospective international 7-day cohort study of outcomes following elective adult inpatient surgery in 27 countries. The primary outcome was in-hospital complications. Secondary outcomes were death following a complication (failure to rescue) and death in hospital. Process measures were admission to critical care immediately after surgery or to treat a complication and duration of hospital stay. A single definition of critical care was used for all countries. RESULTS: A total of 474 hospitals in 19 high-, 7 middle- and 1 low-income country were included in the primary analysis. Data included 44 814 patients with a median hospital stay of 4 (range 2-7) days. A total of 7508 patients (16.8%) developed one or more postoperative complication and 207 died (0.5%). The overall mortality among patients who developed complications was 2.8%. Mortality following complications ranged from 2.4% for pulmonary embolism to 43.9% for cardiac arrest. A total of 4360 (9.7%) patients were admitted to a critical care unit as routine immediately after surgery, of whom 2198 (50.4%) developed a complication, with 105 (2.4%) deaths. A total of 1233 patients (16.4%) were admitted to a critical care unit to treat complications, with 119 (9.7%) deaths. Despite lower baseline risk, outcomes were similar in low- and middle-income compared with high-income countries. CONCLUSIONS: Poor patient outcomes are common after inpatient surgery. Global initiatives to increase access to surgical treatments should also address the need for safe perioperative care. STUDY REGISTRATION: ISRCTN5181700

Evaluation of Supply Variability of Household Water Use in Ilorin Metropolis, North Central Nigeria

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GIS-Based Hydrological Modelling Using Swat: Case Study of Upstream Watershed of Jebba Reservoir in Nigeria

Hydrological modeling tools have been increasingly used worldwide in the management of water resources at watershed level. The application of these tools have been improved in recent time through the advent of remote sensing and Geographical Information System (GIS) techniques which enhance the use of spatially and physically based models to simulate and predict some of the major functions of watershed systems. In this study, the focus was on the applicability and feasibility of SWAT model interfaced with GIS software (MapWindow) in the prediction of stream flow of a watershed located upstream of Jebba reservoir in Nigeria. The flow predictions by SWAT were calibrated (from Jan. 1990 to Dec. 1992) and validated (from Jan.1993 to Dec.1995) against measured flow data while the performance evaluation of the model was achieved using coefficient of determination R2 and Nasch-Sutcliffe Efficiency (NSE). Sensitivity analysis of the model parameters showed that curve number is the most sensitive parameter for estimation of stream flow within the catchment. The model results showed a good correlation with the observed data with values of 0.76 for R2 and 0.72 for NSE   during calibration period. For validation periods, R2 and NSE values were 0.71 and 0.78 respectively. This interesting results of SWAT  is an indication that a properly calibrated SWAT can be an ideal modeling tool for supporting water resources management policies and decisions at watershed level in the region and other river catchments in Nigeri