| 1 |
Author(s):
Idowu Balogun.
Page No : 1-15
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Application of Discriminant Analysis to the Assessment of Seasonal Variability of Groundwater Quality around Municipal Waste Dumpsites within Lagos Metropolis
Abstract
This study assessed the seasonal variability of groundwater quality in the vicinities of AbuleEgba Dumpsite, and the Solous Dumpsites in the Igando area of Lagos, using Discriminant Analysis. This was with the aim of determining the relative contribution of each hydrochemical parameter to the seasonal variation in groundwater quality around the dumpsites. A total of 60 water samples were collected in the vicinities of the dumpsites for the wet and dry seasons and analysed for relevant physico-chemical and heavy metals parameters, using standard analytical methods. The results of the Discriminant Analysis showed that the seasonal variation in groundwater quality around the dumpsites is statistically significant. In the vicinity of the Abule-Egba dumpsite Zn2+, Fe2+, and pH accounted for most of the variation in the wet and dry season groundwater quality while Zn2+, pH and TDS contributed most to the seasonal variation in groundwater quality around the Solous Dumpsites.
| 2 |
Author(s):
S. C. Anijiofor.
Page No : 16-26
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Cost Optimization Model for Effective Solid Waste Management in Minna, Niger State, Nigeria
Abstract
This study examines the application of a cost-optimizing mode for effective solid waste management in Minna, Niger State, in view of the limited funds at the disposal of the State Environmental Protection Agency charged with solid waste management in the state. For this purpose, the town was divided into six zones and waste collection within the zones was monitored for six weeks. A linear programming model was developed to optimize collection of solid waste from the zones to two disposal sites, one existing and one proposed. The basic input data are distances between sources and sink nodes, amount of waste generated, haul cost, equipment, operating and investment cost. The model was solved using Tutorial aid Optimization package software (TORA), a minimum objective value of N128,267.97 was obtained after 24 iterations. When tested with the existing disposal systems, a minimum value of N135,549.67 was obtained after 15 iterations. A total of N7,271.70 will be saved daily and N2,657,820.50 annually, if two disposal sites are used as proposed in the model. It is recommended that the model be adopted to minimize cost of waste disposal system in Minna.
| 3 |
Author(s):
O. A. Idowu.
Page No : 27-35
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Groundwater Prospecting using Geoelectrical Resistivity Method in Abeokuta Metropolis, Southwest Nigeria
Abstract
Aquifers in the hard rock terrain of Abeokuta metropolis and environs in southwestern Nigeria are characterised, using geoelectrical resistivity method with Schlumberger Vertical Electrical Sounding (VES) technique. The study provides insight into the nature of groundwater occurrence, which can guide groundwater exploration and thereby minimise the rate of the occurrence of abortive wells in the study area. Thirty locations were investigated and the VES curves obtained were interpreted and categorised into geoelectric models and type curves for aquifer characterisation. The H, KH, HKH and HAK type curves were obtained. Groundwater occurs, in the study area, within the weathered basement and fractured basement aquifers, which can be as deep as 33 m. A well designed borehole, constructed with appropriate technology, may be crucial for a successful well completion in the study area and areas with similar geology.
| 4 |
Author(s):
S. A. Ngah.
Page No : 36-56
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Patterns of Groundwater Chemistry in Deep Aquifer Systems of the Niger Delta, Nigeria
Abstract
For this study, 57 groundwater samples from deep boreholes, (150- 450m) were analysed with a view to identifying major quality issues and their distribution contrary to pervious studies that were concerned with groundwater from shallow boreholes, less than 150 m in depth. The boreholes were scattered in 5 geomorphologic zones in the Niger Delta. The results revealed that three parameters namely, pH, Cl- and Fe2+ stood out as constituting major groundwater quality issues even in deep aquifers. Values of pH range from 3.8 – 8.4 with 62% of the samples having values outside the NIS 554 permissible limits of 6.5 – 8.5. Slightly acidic groundwater is prevalent in the eastern part of the area including Port Harcourt. All the samples analysed indicated that values for iron ranged from 0.02 – 5.6mg/l with 71% of the samples containing iron in excess of 0.3mg/l which is NIS 554 highest permissible limit. The high iron concentrations occurred in boreholes drilled in the freshwater swamp/meander belt region. Chloride values vary from 5.6 -710mg/l with 18% of the samples showing Cl- concentration in excess of 250mg/l recommended by NIS 554 as maximum permissible concentration in drinking water supplies. Chloride concentration is high particularly in the coastal areas and parts of Port Harcourt city bordering saltwater creeks and tidal channels which have influent relationship with the local groundwater table. Most other parameters fall within NIS 554 limits of acceptability. The study clearly showed that groundwater from even deep aquifers needs to be treated to correct the pH, Cl- and Fe2+ concentration before it can meet NIS 554 standards for drinking water supplies.
| 5 |
Author(s):
Salihu Mustafa.
Page No : 57-69
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Unsteady State Groundwater Flow in Semi-Finite Artesian Aquifer due to Water Level Changes in Bounding Channels
Abstract
In this paper, the flow of ground water induced by variation in water level in two channels bounding a confined aquifer was studied. The water level in each channel varies gradually over time and can be defined by exponential mathematical functions. Analytical solutions were sought to the problem using the Laplace transform method. The values of head were obtained in error functions which can be evaluated at various times and places in the aquifer. A numerical example problem was given in which head values at various places in the aquifer were computed at varying time intervals. Similar results were also obtained for various values of a delay constant introduced in the study and these were compared.
| 6 |
Author(s):
O. I. Ndububa.
Page No : 70-84
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Village Level Operation and Maintenance (VLOM) of Hand Pumps: A Concept for Sustainability of Rural Water Sources in Nigeria
Abstract
The objective of this paper is to present successes achieved in the field by building the capacities of community members, using the Village Level Operation and Maintenance (VLOM) of hand pumps concept document developed by the Federal Ministry of Water Resources.. Activities carried out in 17 selected states in Nigeria included training on maintaining current, valid and up to date data on hand pumps in the states. Other activities included establishing the roles of stakeholders, capacity building for community members on repair and rehabilitation of hand pumps and the establishment of an effective supply chain. Results achieved in the participating states showed that the capacity of the artisans was enhanced. In addition, about 486 non functional hand pumps were rehabilitated, 540 ‘Water Sanitation and Hygiene Committees’ (WASHCOMs) were established during the community mobilization and 22 Spare parts outlets were established. Two states achieved a complete inventory of water sources in the states during the exercise and five of the states achieved wide participation of Local Government Areas (LGA) on capacity building of local mechanics. The paper recommends that VLOM components should be integrated in all new water supply projects and in the implementation of relevant policies.
| 7 |
Author(s):
Grace Oluwasanya.
Page No : 85-109
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The Management of urban self-supply wells in Abeokuta, Nigeria: An assessment and redefinition of roles for water safety planning
Abstract
This paper describes source management practices of self-supply wells in Abeokuta, Nigeria, through a descriptive case study involving semi-structured interviews with open ended questions. The paper detailed perception of users as per source management, the management problems, and factors influencing the identified problems. A major problem is lack of co-operation among resident users. The resident users are further highlighted as managers of self-supply systems. The highlighted role of the resident users showed one of the unique management features of self-supply sources - that is, systems owned by one but managed by many. This management feature is different from communal systems – owned and managed by the community or the public water systems, which are largely owned and managed by the Government. The paper identifies possible solutions, and argues the need for appropriate role definition in water safety development and implementation for the systems in view of the fact that self-supply owners qualify as self-supply sources yet the existing management practices becloud their role definition in water safety plans.
| 8 |
Author(s):
C. I. Ikhile.
Page No : 110-126
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Rainfall Variability in Sections of the Benin-Owena River Basin, Nigeria, and its Implication for Rain-fed Cultivation
Abstract
Rainfall variability and vulnerability to extreme climatic event of drought and flood peaks in sections of the Benin-Owena River Basin was analyzed using a 50-year (1961-2010) longterm rainfall data. Time series data for 50 years was generated and the numbers of wet and dry years were determined after the double mass curve technique was used to verify the consistency of the rainfall data. Benin had 2300 mm annual rainfall compared with a threshold of 1727 mm while the other stations had less. The study reveals that Benin had the most satisfactory rainfall regime with the station being vulnerable to high flood peak and only two (2) of the 50 years under consideration being vulnerable to drought (1972 and 1977), while Akure was found to be the most vulnerable station to extreme climatic failure of drought events as forty-seven (47) of the 50 years experienced unsatisfactory rainfall events lower than the minimum threshold rainfall value for the area. Ado-Ekiti with the lowest rainfall events had 41 years of unsatisfactory rainfall or failure conditions (drought) and Ondo had 37. Apart from Benin, most of the stations had rainfall below the minimum threshold value. The implication here is that the basin is prone to drought hence too risky for rain-fed agriculture. Akure, Ado-Ekiti and Ondo are located in the northern part of the basin where rainfall reliability is low and the risk for failure or vulnerability to drought is high. The highest rainfall ever of 2827.2 mm was recorded in Benin in 2010 season.
