http://196.220.128.81:8080/xmlui/handle/123456789/196 2026-08-12T13:43:59Z http://196.220.128.81:8080/xmlui/handle/123456789/5967 OPTIMAL ALLOCATION AND DISTRIBUTION OF WATER SUPPLY: BABATOLA, JOSIAH OLADELE Many of the Nigerian urban centres are facing erratic water supply due to reasons ranging from socio-economic to technical problems. Urban centres in Ondo and Ekiti States are also faced with these serious water supply problems. This research work carried out socio-economic appraisal the water supply situation of the study area and technical appraisal of the existing water schemes. Results of the appraisal were used to develop two models viz: Allocation of water to demand centres in the most economical way and transmission of water from one headwork to another in the most optimal way to ensure efficient use of the existing water schemes in the study area. To find the best radius or diameter, the construction cost plus the fluid friction loss were expressed in terms of the pipeline size and this function minimized by the procedures of differential calculus. To express the total cost as a function which can be differentiated, the overall size was characterized by one dimension such as radius. This dimension was treated as a variable for computation but as it varied, all other dimensions of the aqueduct cross-section varied accordingly. In this work, water was allocated optimally to consumers where demand is greater than the available supply using the equations that were developed. The rate at which water is supplied to the consumers which is the principal determinant of the cost of the system and the least cost of supply was achieved through optimization techniques. When tested with the local cost data, these equations enable prediction of system costs for variety of design conditions and construction materials. Thus the equations provide the basis for decisions on the basic design variables. The models were tested with data from some water supply schemes in Ondo State. Some specific facts which result from our analysis are presented. The results of this study will be useful to designers, researchers, policy makers and nongovernmental organizations (NGOs) that are involved in water supply activities xx, 174p. : ill. ; 30cm 2004-03-01T00:00:00Z http://196.220.128.81:8080/xmlui/handle/123456789/5966 MODELLING OF SEDIMENT TRANSPORT CAPACITIES OF OGBESE AND OWENA RIVERS IN SOUTH WESTERN NIGERIA OKOLI, CHUKS SHADRACK The movement of sediment such as sand, silt or gravel by flowing water is of interest to a wide range of engineering disciplines. This study is aimed at developing models, which can be used to predict the magnitude and levels of sediment concentration in Ogbese and Owena Rivers in Ondo State. S W. Nigeria for engineering design purposes. Data were collected from field investigations conducted at the respective sampling stations on the two rivers. The live bed concept used was derived from Liu- Hwang (1954) resistance equations " and that of Einstein- Brown (1981) sediment transport concept. The problem was reduced to that of a power law relationship. These data were fitted into the power relationship to obtain the predicted model of the form; F1Q = k2θk1 where the parameters FIQ is the dimensionless sediment discharge θ is the dimensionless bed shear stress, k, and k 2 are sediment transport coefficients. Calibrating the models yielded the values of k1 and k2 for Ogbese river as 0.592 and 0.865 and for Owena river as 0.335 and 1.197 respectively. When tested, the predicted models for Ogbese and Owena rivers performed well in comparison with the established models such as Ackers and White (1973), Engelund and Hansen (1967), Yang (1973) and Karim (1998). It is concluded that the models developed would be useful for engineering design purposes for Ogbese and Owena rivers. These models which relate the sediment discharge, q, to the flow parameters, velocity, v, shear stress, t and the characteristic size of the sediments, d50 are: for Ogbese and Owena. xv, 161p. : ill. ; 30cm 2002-10-01T00:00:00Z http://196.220.128.81:8080/xmlui/handle/123456789/5965 INTRA- MODAL COMPETITION IN URBAN PARA- TRANSIT SYSTEMS: OWOLABI, ADEBAYO OLADIPO This study elucidates on intra-modal competition in urban Para transit system as it affects Akure metropolis. Against the background of the land use areas, transport systems and facilities, and operational characteristic of Para transit mode, modal split trends were studied. Intra-city travel behavior survey was also conducted. The study area was classified into nine zones (according to land use configuration) to facilitate collection or data and their summary. Data on Intra-city travel characteristics were collected through intensive home interview supported by road side interview, rider-ship surveys, general observations and other standard information gathering techniques. Home interviews were conducted using a comprehensive questionnaire covering socio-economic, travel behaviour and level of service features. A simple size of 1 in 10 dwelling units was used in accordance with the recommendation of Bureau of Public Roads. Traffic survey was also conducted using manual counting for one week during morning, afternoon and evening peak periods to determine the characteristics of traffic volume on major roads within Akure metropolis. The overall transport environment of existing transportation of the study area was assessed through the inventory facilities. The analyses of data were done with the aid of computer software such as SPSS and MS-Excel. Volumes of Inter-zonal trip exchanges were estimated and the distributions explained. Modal split trends among the Para-transit modes were used to calibrate standard modal split models (Behavioural Models). The analyses of the modal split trends via the Behavioural Models indicate clearly that both the taxi mode and the motorcycle mode have major inherent advantages especially over the bus mode. These in the author's view could be indices of availability of the modes. The analyses further indicate that long journeys and long waiting time favour the motorcycle mode. Long walking time favour the taxi mode over other modes while short waiting time favour the motorcycle mode. High travel cost favours the motorcycle mode over other modes while low travel cost favours the bus mode. The results and observations of the transit operations within Akure metropolis show that the various modes compete rather than complement one another. This is obviously not to the advantage of the patrons. Besides the limitation due to service characteristics and factors due to inadequacies of operators, institutional issues and environmental factors also combine to accentuate the problems faced by public transport patrons in Akure metropolis. Based on results obtained, an integrated Para-transit scheme for transit service in the study area was proposed and may be extended to similar cities in Nigeria. xvii, 174p. : ill. ; 30cm 2004-09-01T00:00:00Z http://196.220.128.81:8080/xmlui/handle/123456789/5963 GEO-ENVIRONMENTAL ASSESSMENT AND REMEDIATION OF CONTAMINATED SITES: COMMUNITY, LAGOS, NIGERIA OJURI, OLUWAPELUMI OLUMIDE The relationship between hydraulic, chemical and geotechnical properties is of crucial importance for the transport and fate of contaminants in the subsurface (porous media). This research presents a methodology for physical laboratory aquifer modeling, field studies and development of a numerical solute transport model, for the simulation of the laboratory and field experiments. Three-dimensional (3D) sand tank:(I.8 m x 0.3 m x 0.8 m) experiments were conducted to study contaminant transport and natural attenuation within the sand tank. The model was used to study the transport of an inorganic tracer (Chloride) and petroleum hydrocarbon in groundwater, within a tropical aquifer (porous media) material. The research has resulted in the designing and testing of the laboratory aquifer model (3-D sand tank) for subsurface contamination assessment and remediation techniques evaluation. This facility is now available at the Geotechnical Engineering Laboratory, Federal University of Technology, Akure. Detailed geotechnical, hydraulic and geochemical characterization of the chosen laboratory experimental porous media material (Owena sand) and the field site subsurface soil were performed. This will provide basic experimental data on porous media materials, which would be widely useful to geotechnical/environmental researchers and engineers who are involved in contaminated site assessment and remediation in Nigeria. The Owena sand is a poorly graded sand (SP) with 88.1% Sand and 11.9% Gravel. Relevant geotechnical properties of the sand are; Coefficient of uniformity C, = 2.53, coefficient of curvature C, = 0.181, Hydraulic conductivity K = 5.76 X 10-4m/s, Bulk density p = 1.9 Mg/m3, Effective Porosity n, = 0.215 and Median grain diameter D50= 0.55mm. Other relevant hydraulic and solute transport parameters, such as dispersion coefficients and dispersivity were also established for the soil. The numerical model SandModel was developed and used to replicate the laboratory sand tank model and to simulate field conditions at the contaminated Baruwa, Nigeria site. The model simulations predicted patterns of groundwater flow, chloride tracer flux and petroleum hydrocarbon plume advancement/dispersion in the groundwater zone. The method of finite difference was used to solve the 3-D Advection-Dispersion equation, while the FORTRAN computer language was used to code the algorithm and develop the SandModel computer code. The results were displayed graphically using the MATLAB application package. The Laboratory and Field-Scale SandModel is applicable to conservative and reactive solute transport modeling at the laboratory and field scale configuration and has been validated for porous media materials. The plots of the tracer breakthrough curves (TBCs) for the twelve (12) multi-level observation points within the model domain show a reasonable match of the simulated and observed tracer breakthrough curves. Calculated t (paired-t-statistic (student t quantile) value for each observation well is less than the critical value of t (tcritical = 2.16 for df=13), and the calculated P value for each well is greater than the chosen significance level (p=0.05), therefore the null (no difference) between observed and simulated data sets hypothesis is accepted. The analysis also reveals high to very high correlation (R2=O.79 to R2=O.91) between the observed and simulated values. A sensitivity analysts showed that the time required for complete source depletion, was most dependent on the source definition, biodegradation rate and the hydraulic conductivity K of the porous medium. Soil particle size (D50) and hydraulic conductivity (K) data have been used to establish a correlation between the hydrodynamic transport parameters (Dispersivity [α]) for the laboratory and field porous media soils. The proposed empirical relation for the determination of the field dispersivity [α] parameter is; D50(L) (KCL)/ D50(F) K(F) = α (F)/ α(L) A Retardation factor, R = 2.5, and biodegradation rate of 0.0004/day (half life of 5 years) were obtained from the model calibration for BTEX. A clean-up time for BTEX of about 45 years was estimated by natural attenuation from model predictions. The results are highly relevant in the light of the increasing awareness of the precarious trend of lack of monitoring and remedial feasibility data for the subsoil environment in the thousands of gasoline fuel stations, and petroleum storage/distribution underground infrastructure in Nigeria. xvii, 174p. : ill. ; 30cm 2009-12-01T00:00:00Z