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Hydrogeochemical Model and Water Quality of Groundwater in the Granito-Basaltic Fractured Rock Aquiferous Formations in Bafoussam, West Region-Cameroon  [PDF]
R. A. Akoachere, T. A. Eyong, M. O. Eduvie, S. E. Egbe, O. O. Yaya, M. O. Nwude
Journal of Water Resource and Protection (JWARP) , 2018, DOI: 10.4236/jwarp.2018.1011068
Abstract: This study determined the hydrogeochemical model of groundwater and groundwater domestic-agro-industrial quality in Bafoussam using hydrogeochemical tools and physicochemical parameters: Ionic ratios, Gibbs diagrams, Piper diagrams, Durov diagrams and water quality indices. From physicochemical parameters; pH ranged from, 4.47 - 7.84; EC, 10 - 820 μS/cm; Temperature, 22.3°C - 29.5°C and TDS, 6.7 - 549.4 mg/L. The major ions fell below WHO acceptable limits. The sequences of major ionic abundance are: Ca2+ > Mg2+ > K+ > Na+ > NH+4, HCO-3 > Cl- > SO2-4 > NO3 > HPO2-4. Recharge by atmospheric precipitation, ion-exchange and simple dissolution processes are responsible for groundwater character, ionic content resulted from ion exchange and rock-weathering. Water types are Ca-HCO3 and Ca-Cl Hydrogeochemical facies are Ca-Mg-Cl-SO4 and Ca-Mg-HCO3. Domestic water quality was determined by use of pH, electrical Conductivity EC, total dissolved solids TDS, total Hardness HT and water quality index WQI. WQI values ranged from 0 - 42.09 and HT 67.89 - 339.01 indicating that water is of good domestic quality. Agro-industrial suitability of groundwater was determined using, sodium adsorption ratio SAR, permeability index PI, Magnesium adsorption ratio MAR, percent sodium %Na, Kelly’s ratio KR and Residual sodium carbonate RSC and Wilcox diagram; From irrigational water suitability parameters, SAR values ranged from 0.01 - 0 05; %Na 3.69 - 15.50; KR 0.005 - 0.023; PI 1.04 - 67.98; MAR 2.89 - 55.27; RSC -5.22 to -0.44 and Wilcox diagram indicate that inorganic groundwater content in the study area is excellent-good for irrigation; this is of significance since Bafoussam a major agroindustrial zone in Cameroon and Central Africa is in the process of developing large scaled irrigation based agricultural projects dependent on use of surface and groundwater. Recharge from precipitation exchanges ions with the weathered country rocks and mixes with regional flow in a generally south-east north-westerly direction by piston flow in the granito-basaltic aquiferous formations in Bafoussam. There is need for detailed studies to determine aquifer
Management of a Karoo fractured-rock aquifer system – Kalkveld Water User Association (WUA)
BH Usher, JA Pretorius, GJ van Tonder
Water SA , 2005,
Abstract: Due to large-scale development of groundwater resources for irrigation purposes the Kalkveld area has been identified by DWAF as an area where a water user association (WUA) should be established in order to achieve better management of the resource. The area represents typical Karoo type fractured-rock aquifers, which consist mainly of sandstone, mudstone, shale and siltstone. The majority of boreholes drilled in Karoo formations have very low immediate yields (<1 /s). However, large volumes of groundwater are pumped from boreholes in the Kalkveld area for irrigation of commercial crops. Thus, these aquifers have a more complex and unpredictable behaviour than normally described in the literature. Groundwater management units have been delineated based on: similar hydraulic properties; recharge characteristics; land use; geology (including the distribution of surface calcrete deposits); rainfall; and hydrochemistry. A numerical flow model was constructed for the area to evaluate the impact of increased abstraction on the groundwater resources as well as to evaluate the response of the delineated water management units/areas. To facilitate long-term management of the groundwater resources a user-friendly prediction and management tool was developed. The tool together with the recommended monitoring and management measures should enable DWAF and the WUA to manage the groundwater resource in a sustainable manner. Water SA Vol 32(1)pp:9-19
Hydrogeophysical Parameters Estimation for Aquifer Characterisation in Hard Rock Environment: A Case Study from Yaounde, Cameroon  [PDF]
William Assatsé Teikeu, Philippe Nouck Njandjock, Dieudonné Bisso, Quentin Yene Atangana, Jean-Paul Sep Nlomgan
Journal of Water Resource and Protection (JWARP) , 2012, DOI: 10.4236/jwarp.2012.411110
Abstract: Detailed local geological and hydrogeophysical investigations were carried out for the aquifer in Yaoundé, Cameroon to delineate the architecture of different subsurface geological horizons using lithologs and generated vertical electrical sounding (VES) data. An attempt has also been made to estimate aquifer transmissivity from resistivity data. The transmissivity of the uncon?ned aquifer was computed by determining the Dar-Zarrouk parameters (longitudinal unit conductance and transverse unit resistance) and were compared with the actual field transmissivity. The results showed a direct relation between aquifer transmissivity and transverse resistance. The relationship established has therefore, been generalized in the study area in order to evaluate hydraulic conductivity and transmissivity at all the points where geoelectrical measurements have been carried out. This generalization allows one to derive maps of the product Kσ and transmissivity in the study area based on geoelectrical measurements. These maps are important in future modelling processes oriented towards better exploitation of the aquifers.
Interpretation of Groundwater Flow into Fractured Aquifer  [PDF]
Sameh W. Al-Muqdadi, Broder J. Merkel
International Journal of Geosciences (IJG) , 2012, DOI: 10.4236/ijg.2012.32039
Abstract: The region of investigation is part of the western desert of Iraq covering an area of about 12,400 km2, this region includes several large wadis discharging to the Euphrates River. Since the Tectonic features in particular fault zones play a significant role with respect to groundwater flow in hard rock terrains. The present research is focus on investigate lineaments that have been classified as suspected faults by means of remote sensing techniques and digital terrain evaluation in combination with interpolating groundwater heads and MLU pumping tests model in a fractured rock aquifer, Lineaments extraction approach is illustrated a fare matching with suspected faults, moreover these lineaments conducted an elevated permeability zone.
Groundwater Monitoring in the Gneisso-Basaltic Fractured Rock Aquiferous Formations of Kumba, Southwest Region Cameroon: Seasonal Variations in the Aqueous Geochemistry and Water Quality  [PDF]
R. A. Akoachere, Y. M. Ngwese, S. E. Egbe, T. A. Eyong, S. N. Edimo, D. B. Tambe
Journal of Geoscience and Environment Protection (GEP) , 2018, DOI: 10.4236/gep.2018.611003
Abstract: The objective was to determine and monitor seasonal changes during four hydrological seasons: Wet season (September), Wetdry season (December), Dry season (March) and Drywet season (June) in the groundwater aqueous geochemistry and its domestic-agro-industrial quality using physicochemical parameters and hydrogeochemical tools: Temperature, Electrical Conductivity EC, pH, Total dissolved solids TDS, Ionic ratios, Gibbs diagrams, Piper diagrams Durov diagrams, total hardness HT, Water quality index WQI, Sodium adsorption ratio SAR, Percent Sodium %Na, Kelly’s Ratio KR, permeability index PI, Magnesium adsorption ratio MAR, Residual sodium carbonate RSC and Wilcox diagram. Field physicochemical parameters ranged from: Wet season; pH 3.9 - 6.9; Temperature, 23.3°C - 29.1°C; EC, 10 - 1900 μS/cm; TDS, 6.7 - 1273 mg/L; Wetdry, pH, 5.7 - 11.7; Temperature, 23.6°C - 28.3°C; EC, 1 - 1099 μS/cm, TDS, 0.67 - 736.33 mg/L; Dry pH, 5.7 - 13.1; Temperature, 26.3°C - 30.2°C; EC, 12 - 770 μS/cm, TDS, 8.04 - 515.9 mg/L and Drywet, pH, 4 - 7.4; Temperature, 25.8°C - 30.7°C; EC, 10 - 1220 μS/cm, TDS, 6.7 - 817.4 mg/L. Seventy-two groundwater samples, 18 per season were analysed. All ionic concentrations fell below acceptable World Health Organization guidelines in all seasons. The sequence of abundance of major ions are; Wet, Ca+ > Mg2+ > Na+ = K+ > NH4+, HCO3? > Cl? > NO3? > SO42? > HPO42?; Wetdry Ca+ > K+ > Mg2+ > Na+ > NH4+, HCO3? > Cl? > SO42? > NO3? > HPO42?; Dry Ca+ > K+ > Mg2+ > Na+ > NH4+, HCO3? > Cl?> NO3? > SO42? > HPO42?; Drywet NH4+ > Ca+ > K+ > Mg2+ > Na+; Cl? > HCO3? > NO3? > SO42? > HPO42?. Groundwater ionic content was due to rock weathering and ion exchange reactions. CaSO4 is the dominant water type in Wet and Wetdry seasons; followed by CaHCO3, Na + K-Cl Wet, CaSO4 and
Analytical and Numerical Modeling of Flow in a Fractured Gneiss Aquifer  [PDF]
Ramadan Abdelaziz, Broder J. Merkel
Journal of Water Resource and Protection (JWARP) , 2012, DOI: 10.4236/jwarp.2012.48076
Abstract: Investigating and modeling fluid flow in fractured aquifers is a challenge. This study presents the results of a series of packer tests conducted in a fractured aquifer in Freiberg, Germany, where gneiss is the dominant rock type. Two methods were applied to acquire hydraulic properties from the packer tests: analytical and numerical modeling. MLU (Multi-Layer Unsteady state) for Windows is the analytical model that was applied. ANSYS-FLOTRAN was used to build a two-dimensional numerical model of the geometry of the layered aquifer. A reasonable match between experimental data and simulated data was achieved with the 2D numerical model while the solution from the analytical model revealed significant deviations with respect to direction.
The applicability of slug tests in fractured-rock formations
GJ van Tonder, PD Vermeulen
Water SA , 2005,
Abstract: Currently slug tests in South Africa are used with two objectives in mind: To get a first estimate of the yield of a borehole To estimate the K-value (or T-value) of the aquifer near the borehole. The paper shows that the use of currently available slug-test interpretation methods to analyse slug tests in fractured-rock aquifers to estimate a T or K-value is problematic. The estimated value is dependent on the flow thickness (thickness of the part of the aquifer in which flow occurs due to the slug input). If this thickness of flow is known, the estimated T-value is more representative of that of the fracture zone. By using the total thickness of the formation for the estimation of the K-value in slug-test analysis, the estimated K-value (and thus KD-value) does not represent the T-value of the formation. Water SA Vol. 31 (2) 2005: pp.157-160
Lattice Boltzmann modeling for tracer test analysis in a fractured Gneiss aquifer  [PDF]
Ramadan Abdelaziz, Andrew J. Pearson, Broder J. Merkel
Natural Science (NS) , 2013, DOI: 10.4236/ns.2013.53050
Abstract:

Fractured Gneiss aquifers present a challenge to hydrogeologists because of their geological complexity. Interpretation methods which can be applied to porous media cannot be applied to fractured Gneiss aquifers because flow and transport occur in fractures, joints, and conduits. In contrast, the rock matrix contribution to groundwater flow is not very important in Gneiss aquifers. Sodium chloride was injected into groundwater flow under steady state condition as tracer to determine transport parameters which are needed for transport modeling. QTRACER2 was used to evaluate the tracer test data. Lattice Boltzmann method was applied to simulate flow and tracer transport through a fracture zone in Gneiss. Experimental tracer data and the numerical solution by lattice Boltzmann method are compared. In general, the results indicate that a 2D Lattice Boltzmann model is able to simulate solute transport in fractured gneiss aquifer at field scale level.

Hydrogeochemical Processes of Alkhobar Aquifer in Eastern Region, Saudi Arabia  [PDF]
Abdullah I. Al-Zarah
Journal of Applied Sciences , 2007,
Abstract: A field investigation was carried out to determine the Physical and chemical characteristics of Al-Khobar aquifer in the Eastern region of Saudi Arabia. Total Dissolved Solids (TDS) varies from 4400 mg L-1 along the Gulf coast on the eastern side to around 1800 mg L-1 on the western side. Sodium (Na) is the dominant cation followed by Mg, Ca and K in descending order. Whereas, the anion concentration order is Cl > SO4 > HCO3. Nitrate concentration was found to be higher than the recommended limit for drinking purposes. The Saturation Indices (SI) indicated that the regional groundwater is under-saturated with respect to calcite, dolomite, gypsum, anhydrite, halite, pyrite and aragonite minerals and oversaturated with respect to goethite and hematite minerals. The hardness of groundwater is very high as compared to the established standards. The F contents are within permissible limits for drinking. The nitrate contents are within permissible limits for domestic use. Two water types i.e., Na-Ca-Cl-SO4 and Na-Ca-Mg-Cl-SO4 dominate the Al-Ahsa whereas Na-Ca-Cl and Na-Ca-Cl-SO4 water types are dominant in Al-Dammam, Al-Khobar and Al-Qatif areas. Overall, the study provided useful information on some important hydrogeochemical processes in groundwater of the eastern region. Further studies are required to determine heavy trace metals concentration for multiple uses.
Submarine groundwater discharge (SGD) patterns through a fractured rock: a case study in the Ubatuba coastal area, Brazil
Bokuniewicz,Henry; Kontar,Evgeny; Rodrigues,Marcelo; Klein,Daniel Andreas;
Revista de la Asociaci?3n Argentina de Sedimentolog?-a , 2004,
Abstract: the flow of groundwater out across the sea floor has the potential to influence sedimentary processes, sea floor morphology, pore water chemistry and benthic habitats. relatively few observations of the process of submarine groundwater discharge (sgd) have been made. measurements along the south american coast and over fractured rock aquifers are especially rare. the rate and distribution of sgd was measured using vented, benthic chambers on the floor of flamengo bay located at the southeast coast of brazil. discharge rates were found exceeding 200 cm3 s-1 of pore water per cm2 of sea floor per day (200 cm day-1). large variations in sgd rates were seen over distances of a few meters. we attribute the variation to the geomorphologic features of the fracture rock aquifer underlying a thin blanket of coastal sediments. clustering of fractures and the topography of the rock-sediment interface might be focusing or dispersing the discharge of groundwater.
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